On Wed, Mar 22, 2017 at 12:31:13AM +0800, fu.wei@linaro.org wrote:

From: Fu Wei fu.wei@linaro.org

Currently, the counter frequency detection call(arch_timer_detect_rate) includes getting the frequency from the device-tree property, the per-cpu arch-timer and the memory-mapped (MMIO) timer interfaces. But reading device-tree property will be needed only when system boot with device-tree, and reading from the per-cpu arch-timer and the memory-mapped (MMIO) timer interfaces will be needed only when the system initializes the relevant timer.

This patch separates out device-tree code, keep them in device-tree init function, and removes arch_timer_detect_rate founction, then uses the arch_timer_get_cntfrq and arch_timer_mem_get_cntfrq directly.

Signed-off-by: Fu Wei fu.wei@linaro.org

drivers/clocksource/arm_arch_timer.c | 58 +++++++++++++++++++----------------- 1 file changed, 30 insertions(+), 28 deletions(-)

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 843f923..29ca7d6 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -560,30 +560,6 @@ static u32 arch_timer_mem_get_cntfrq(void __iomem *cntbase) return readl_relaxed(cntbase + CNTFRQ); } -static void -arch_timer_detect_rate(void __iomem *cntbase, struct device_node *np) -{

• /* Who has more than one independent system counter? */
• if (arch_timer_rate)

• return;
  

• /*

• * Try to determine the frequency from the device tree or CNTFRQ,
  

• * if ACPI is enabled, get the frequency from CNTFRQ ONLY.
  

• */
  

• if (!acpi_disabled ||

•    of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) {
  

• if (cntbase)
  

• 	arch_timer_rate = arch_timer_mem_get_cntfrq(cntbase);
  

• else
  

• 	arch_timer_rate = arch_timer_get_cntfrq();
  

• }
• /* Check the timer frequency. */
• if (arch_timer_rate == 0)

• pr_warn("frequency not available\n");
  

-}

static void arch_timer_banner(unsigned type) { pr_info("%s%s%s timer(s) running at %lu.%02luMHz (%s%s%s).\n", @@ -958,7 +934,17 @@ static int __init arch_timer_of_init(struct device_node *np) for (i = ARCH_TIMER_PHYS_SECURE_PPI; i < ARCH_TIMER_MAX_TIMER_PPI; i++) arch_timer_ppi[i] = irq_of_parse_and_map(np, i);

• arch_timer_detect_rate(NULL, np);

• /*

• * Try to determine the frequency from the device tree,
  

• * if fail, get the frequency from the sysreg CNTFRQ.
  

• */
  

• if (!arch_timer_rate &&

This variable is set only if "arm,armv7-timer" and "arm,armv7-timer-mem" are declared together in the DT, right ?

Two declarations for a single variable ? Ignore the !arch_timer_rate.

•    of_property_read_u32(np, "clock-frequency", &arch_timer_rate))
  

• arch_timer_rate = arch_timer_get_cntfrq();
  

• if (!arch_timer_rate) {

• pr_err(FW_BUG "frequency not available.\n");
  

• return -EINVAL;
  

• }

Please, clarify this block, the conditions are unclear.

arch_timer_c3stop = !of_property_read_bool(np, "always-on"); @@ -1069,7 +1055,19 @@ static int __init arch_timer_mem_init(struct device_node *np) goto out; }

• arch_timer_detect_rate(base, np);

• /*

• * Try to determine the frequency from the device tree,
  

• * if fail, get the frequency from the CNTFRQ reg of MMIO timer.
  

• */
  

• if (!arch_timer_rate &&

•    of_property_read_u32(np, "clock-frequency", &arch_timer_rate))
  

• arch_timer_rate = arch_timer_mem_get_cntfrq(base);
  

• if (!arch_timer_rate) {

• pr_err(FW_BUG "MMIO frequency not available.\n");
  

• ret = -EINVAL;
  

• goto out;
  

• }
• ret = arch_timer_mem_register(base, irq); if (ret) goto out;

@@ -1130,8 +1128,12 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *table) map_generic_timer_interrupt(gtdt->non_secure_el2_interrupt, gtdt->non_secure_el2_flags);

• /* Get the frequency from CNTFRQ */
• arch_timer_detect_rate(NULL, NULL);

• /* Get the frequency from the sysreg CNTFRQ */
• arch_timer_rate = arch_timer_get_cntfrq();
• if (!arch_timer_rate) {

• pr_err(FW_BUG "frequency not available.\n");
  

• return -EINVAL;
  

• }

arch_timer_uses_ppi = arch_timer_select_ppi(); if (!arch_timer_ppi[arch_timer_uses_ppi]) { -- 2.9.3

Hi Daniel,

On 29 March 2017 at 11:41, Fu Wei fu.wei@linaro.org wrote:

Hi Daniel,

Great thanks for your review, allow me to answer your question below:

On 28 March 2017 at 22:58, Daniel Lezcano daniel.lezcano@linaro.org wrote:

...

On Wed, Mar 22, 2017 at 12:31:13AM +0800, fu.wei@linaro.org wrote:

...

From: Fu Wei fu.wei@linaro.org

Currently, the counter frequency detection call(arch_timer_detect_rate) includes getting the frequency from the device-tree property, the per-cpu arch-timer and the memory-mapped (MMIO) timer interfaces. But reading device-tree property will be needed only when system boot with device-tree, and reading from the per-cpu arch-timer and the memory-mapped (MMIO) timer interfaces will be needed only when the system initializes the relevant timer.

This patch separates out device-tree code, keep them in device-tree init function, and removes arch_timer_detect_rate founction, then uses the arch_timer_get_cntfrq and arch_timer_mem_get_cntfrq directly.

Signed-off-by: Fu Wei fu.wei@linaro.org

drivers/clocksource/arm_arch_timer.c | 58 +++++++++++++++++++----------------- 1 file changed, 30 insertions(+), 28 deletions(-)

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 843f923..29ca7d6 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -560,30 +560,6 @@ static u32 arch_timer_mem_get_cntfrq(void __iomem *cntbase) return readl_relaxed(cntbase + CNTFRQ); }

-static void -arch_timer_detect_rate(void __iomem *cntbase, struct device_node *np) -{

• /* Who has more than one independent system counter? */
  

• if (arch_timer_rate)
  

•         return;
  

• /*
  

•  * Try to determine the frequency from the device tree or CNTFRQ,
  

•  * if ACPI is enabled, get the frequency from CNTFRQ ONLY.
  

•  */
  

• if (!acpi_disabled ||
  

•     of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) {
  

•         if (cntbase)
  

•                 arch_timer_rate = arch_timer_mem_get_cntfrq(cntbase);
  

•         else
  

•                 arch_timer_rate = arch_timer_get_cntfrq();
  

• }
  

• /* Check the timer frequency. */
  

• if (arch_timer_rate == 0)
  

•         pr_warn("frequency not available\n");
  

-}

static void arch_timer_banner(unsigned type) { pr_info("%s%s%s timer(s) running at %lu.%02luMHz (%s%s%s).\n", @@ -958,7 +934,17 @@ static int __init arch_timer_of_init(struct device_node *np) for (i = ARCH_TIMER_PHYS_SECURE_PPI; i < ARCH_TIMER_MAX_TIMER_PPI; i++) arch_timer_ppi[i] = irq_of_parse_and_map(np, i);

• arch_timer_detect_rate(NULL, np);
  

• /*
  

•  * Try to determine the frequency from the device tree,
  

•  * if fail, get the frequency from the sysreg CNTFRQ.
  

•  */
  

• if (!arch_timer_rate &&
  

This variable is set only if "arm,armv7-timer" and "arm,armv7-timer-mem" are declared together in the DT, right ?

Two declarations for a single variable ? Ignore the !arch_timer_rate.

In this function, we try to initialize per-CPU arm arch_timer by DT. this "!arch_timer_rate" is for testing that if we have got system counter frequency from the memory-mapped timer. If so, we just skip getting the frequency from DT or sysreg cntfrq again. This variable is set only if "arm,armv7-timer-mem" is initialized earlier than "arm,armv7-timer", in another word, maybe the node of "arm,armv7-timer-mem" is declared earlier than "arm,armv7-timer-mem" one in DT.

we do this check is for keeping the same init logic as before in the DT, try to avoid any possibility of breaking devices which boot by DT.

...

...

•     of_property_read_u32(np, "clock-frequency", &arch_timer_rate))
  

•         arch_timer_rate = arch_timer_get_cntfrq();
  

• if (!arch_timer_rate) {
  

•         pr_err(FW_BUG "frequency not available.\n");
  

•         return -EINVAL;
  

• }
  

Please, clarify this block, the conditions are unclear.

this "!arch_timer_rate" is for verifying that if the system counter frequency we just got from DT or sysreg cntfrq is valid(non-zero).

So here, you can see I check arch_timer_rate twice, but they are for different cases.

I think about this several times, For this block, it is a little unclear, so I think this will be better:

+ /* + * Try to determine the frequency: + * If we have got it in arch_timer_mem_of_init, we don't need to get it again, skip. + * Otherwise, try to get the frequency from the device tree, + * if fail, try to get it from the sysreg CNTFRQ. + * Last, verify the arch_timer_rate before leaving this block. + */ + if (!arch_timer_rate) { + if (of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) + arch_timer_rate = arch_timer_get_cntfrq(); + if (!arch_timer_rate) { + pr_err(FW_BUG "frequency not available.\n"); + return -EINVAL; + } + }

...

...

  arch_timer_c3stop = !of_property_read_bool(np, "always-on");

@@ -1069,7 +1055,19 @@ static int __init arch_timer_mem_init(struct device_node *np) goto out; }

• arch_timer_detect_rate(base, np);
  

• /*
  

•  * Try to determine the frequency from the device tree,
  

•  * if fail, get the frequency from the CNTFRQ reg of MMIO timer.
  

•  */
  

• if (!arch_timer_rate &&
  

•     of_property_read_u32(np, "clock-frequency", &arch_timer_rate))
  

•         arch_timer_rate = arch_timer_mem_get_cntfrq(base);
  

• if (!arch_timer_rate) {
  

•         pr_err(FW_BUG "MMIO frequency not available.\n");
  

•         ret = -EINVAL;
  

•         goto out;
  

• }
  

• ret = arch_timer_mem_register(base, irq);
  if (ret)
          goto out;
  

@@ -1130,8 +1128,12 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *table) map_generic_timer_interrupt(gtdt->non_secure_el2_interrupt, gtdt->non_secure_el2_flags);

• /* Get the frequency from CNTFRQ */
  

• arch_timer_detect_rate(NULL, NULL);
  

• /* Get the frequency from the sysreg CNTFRQ */
  

• arch_timer_rate = arch_timer_get_cntfrq();
  

• if (!arch_timer_rate) {
  

•         pr_err(FW_BUG "frequency not available.\n");
  

•         return -EINVAL;
  

• }
  
  arch_timer_uses_ppi = arch_timer_select_ppi();
  if (!arch_timer_ppi[arch_timer_uses_ppi]) {
  

-- 2.9.3

--

http://www.linaro.org/ Linaro.org │ Open source software for ARM SoCs

Follow Linaro: http://www.facebook.com/pages/Linaro Facebook | http://twitter.com/#!/linaroorg Twitter | http://www.linaro.org/linaro-blog/ Blog

-- Best regards,

Fu Wei Software Engineer Red Hat

On 29 March 2017 at 22:41, Daniel Lezcano daniel.lezcano@linaro.org wrote:

On Wed, Mar 29, 2017 at 01:11:58PM +0800, Fu Wei wrote:

...

Hi Daniel,

On 29 March 2017 at 11:41, Fu Wei fu.wei@linaro.org wrote:

...

Hi Daniel,

Great thanks for your review, allow me to answer your question below:

On 28 March 2017 at 22:58, Daniel Lezcano daniel.lezcano@linaro.org wrote:

...

On Wed, Mar 22, 2017 at 12:31:13AM +0800, fu.wei@linaro.org wrote:

...

From: Fu Wei fu.wei@linaro.org

Currently, the counter frequency detection call(arch_timer_detect_rate) includes getting the frequency from the device-tree property, the per-cpu arch-timer and the memory-mapped (MMIO) timer interfaces. But reading device-tree property will be needed only when system boot with device-tree, and reading from the per-cpu arch-timer and the memory-mapped (MMIO) timer interfaces will be needed only when the system initializes the relevant timer.

This patch separates out device-tree code, keep them in device-tree init function, and removes arch_timer_detect_rate founction, then uses the arch_timer_get_cntfrq and arch_timer_mem_get_cntfrq directly.

Signed-off-by: Fu Wei fu.wei@linaro.org

drivers/clocksource/arm_arch_timer.c | 58 +++++++++++++++++++----------------- 1 file changed, 30 insertions(+), 28 deletions(-)

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 843f923..29ca7d6 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -560,30 +560,6 @@ static u32 arch_timer_mem_get_cntfrq(void __iomem *cntbase) return readl_relaxed(cntbase + CNTFRQ); }

-static void -arch_timer_detect_rate(void __iomem *cntbase, struct device_node *np) -{

• /* Who has more than one independent system counter? */
  

• if (arch_timer_rate)
  

•         return;
  

• /*
  

•  * Try to determine the frequency from the device tree or CNTFRQ,
  

•  * if ACPI is enabled, get the frequency from CNTFRQ ONLY.
  

•  */
  

• if (!acpi_disabled ||
  

•     of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) {
  

•         if (cntbase)
  

•                 arch_timer_rate = arch_timer_mem_get_cntfrq(cntbase);
  

•         else
  

•                 arch_timer_rate = arch_timer_get_cntfrq();
  

• }
  

• /* Check the timer frequency. */
  

• if (arch_timer_rate == 0)
  

•         pr_warn("frequency not available\n");
  

-}

static void arch_timer_banner(unsigned type) { pr_info("%s%s%s timer(s) running at %lu.%02luMHz (%s%s%s).\n", @@ -958,7 +934,17 @@ static int __init arch_timer_of_init(struct device_node *np) for (i = ARCH_TIMER_PHYS_SECURE_PPI; i < ARCH_TIMER_MAX_TIMER_PPI; i++) arch_timer_ppi[i] = irq_of_parse_and_map(np, i);

• arch_timer_detect_rate(NULL, np);
  

• /*
  

•  * Try to determine the frequency from the device tree,
  

•  * if fail, get the frequency from the sysreg CNTFRQ.
  

•  */
  

• if (!arch_timer_rate &&
  

This variable is set only if "arm,armv7-timer" and "arm,armv7-timer-mem" are declared together in the DT, right ?

Two declarations for a single variable ? Ignore the !arch_timer_rate.

In this function, we try to initialize per-CPU arm arch_timer by DT. this "!arch_timer_rate" is for testing that if we have got system counter frequency from the memory-mapped timer. If so, we just skip getting the frequency from DT or sysreg cntfrq again. This variable is set only if "arm,armv7-timer-mem" is initialized earlier than "arm,armv7-timer", in another word, maybe the node of "arm,armv7-timer-mem" is declared earlier than "arm,armv7-timer-mem" one in DT.

we do this check is for keeping the same init logic as before in the DT, try to avoid any possibility of breaking devices which boot by DT.

...

...

•     of_property_read_u32(np, "clock-frequency", &arch_timer_rate))
  

•         arch_timer_rate = arch_timer_get_cntfrq();
  

• if (!arch_timer_rate) {
  

•         pr_err(FW_BUG "frequency not available.\n");
  

•         return -EINVAL;
  

• }
  

Please, clarify this block, the conditions are unclear.

this "!arch_timer_rate" is for verifying that if the system counter frequency we just got from DT or sysreg cntfrq is valid(non-zero).

So here, you can see I check arch_timer_rate twice, but they are for different cases.

I think about this several times, For this block, it is a little unclear, so I think this will be better:

• /*
• • Try to determine the frequency:
• • If we have got it in arch_timer_mem_of_init, we don't need to get

it again, skip.

• • Otherwise, try to get the frequency from the device tree,
• • if fail, try to get it from the sysreg CNTFRQ.
• • Last, verify the arch_timer_rate before leaving this block.
• */
• if (!arch_timer_rate) {

•     if (of_property_read_u32(np, "clock-frequency", &arch_timer_rate))
  

•             arch_timer_rate = arch_timer_get_cntfrq();
  

•     if (!arch_timer_rate) {
  

•             pr_err(FW_BUG "frequency not available.\n");
  

•             return -EINVAL;
  

•     }
  

• }

Hi Fu Wei,

in my previous comment, I was suggesting to remove the first arch_timer_rate check.

The code assumes something else initialized this variable. There is clearly a conflict in the variable assignment. So if a node is defined twice for this variable, then it is more sane to consider the second pass overwrites the first one. As the DT are specifying the same rate, for -mem and !-mem, then it should have not an impact (to be verified).

So the code will be like this:

+ /* + * Try to determine the frequency: + * If we try to get the frequency from the device tree, + * if fail, try to get it from the sysreg CNTFRQ. + * Then verify the arch_timer_rate. + */ + if (of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) + arch_timer_rate = arch_timer_get_cntfrq(); + if (!arch_timer_rate) { + pr_err(FW_BUG "frequency not available.\n"); + return -EINVAL; + }

I am OK to delete the first arch_timer_rate check, If arch_timer_mem is initialized first, we just overwrite the existing rate to arch_timer rate. This makes sense to me.

On Wed, Mar 22, 2017 at 12:31:14AM +0800, fu.wei@linaro.org wrote:

From: Fu Wei fu.wei@linaro.org

When system init with device-tree, we don't know which node will be initialized first. And the code in arch_timer_common_init should wait until per-cpu timer and MMIO timer are both initialized. So we need arch_timer_needs_probing to detect the init status of system.

But currently the code is dispersed in arch_timer_needs_probing and arch_timer_common_init. And the function name doesn't specify that it's only for device-tree. This is somewhat confusing.

Can the following patch help you to solve nicely the situation ?

https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1360007.html

This patch move all related code from arch_timer_common_init to arch_timer_needs_probing, refactor it, and rename it to arch_timer_needs_of_probing. And make sure that it will be called only if acpi is disabled.

Signed-off-by: Fu Wei fu.wei@linaro.org Reviewed-by: Hanjun Guo hanjun.guo@linaro.org

---

drivers/clocksource/arm_arch_timer.c | 34 +++++++++++++++++++--------------- 1 file changed, 19 insertions(+), 15 deletions(-)

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 29ca7d6..d1a05d9 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -839,15 +839,28 @@ static const struct of_device_id arch_timer_mem_of_match[] __initconst = { {}, }; -static bool __init -arch_timer_needs_probing(int type, const struct of_device_id *matches) +static bool __init arch_timer_needs_of_probing(void) { struct device_node *dn; bool needs_probing = false;

• unsigned int mask = ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM;

• dn = of_find_matching_node(NULL, matches);
• if (dn && of_device_is_available(dn) && !(arch_timers_present & type))

• /* We have two timers, and both device-tree nodes are probed. */
• if ((arch_timers_present & mask) == mask)

• return false;
  

• /*

• * Only one type of timer is probed,
  

• * check if we have another type of timer node in device-tree.
  

• */
  

• if (arch_timers_present & ARCH_TIMER_TYPE_CP15)

• dn = of_find_matching_node(NULL, arch_timer_mem_of_match);
  

• else

• dn = of_find_matching_node(NULL, arch_timer_of_match);
  

• if (dn && of_device_is_available(dn)) needs_probing = true;
• of_node_put(dn);

return needs_probing; @@ -855,17 +868,8 @@ arch_timer_needs_probing(int type, const struct of_device_id *matches) static int __init arch_timer_common_init(void) {

• unsigned mask = ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM;
• /* Wait until both nodes are probed if we have two timers */
• if ((arch_timers_present & mask) != mask) {

• if (arch_timer_needs_probing(ARCH_TIMER_TYPE_MEM,
  

• 			     arch_timer_mem_of_match))
  

• 	return 0;
  

• if (arch_timer_needs_probing(ARCH_TIMER_TYPE_CP15,
  

• 			     arch_timer_of_match))
  

• 	return 0;
  

• }

• if (acpi_disabled && arch_timer_needs_of_probing())

• return 0;
  

arch_timer_banner(arch_timers_present); arch_counter_register(arch_timers_present); -- 2.9.3

Hi Lorenzo,

Great thanks for your review and help, I will take most of your suggestions, But one or two comments have been discussed in previous patchset, please allow me to explain these. :-)

On 28 March 2017 at 19:35, Lorenzo Pieralisi lorenzo.pieralisi@arm.com wrote:

On Wed, Mar 22, 2017 at 12:31:18AM +0800, fu.wei@linaro.org wrote:

...

From: Fu Wei fu.wei@linaro.org

This patch adds support for parsing arch timer info in GTDT, provides some kernel APIs to parse all the PPIs and always-on info in GTDT and export them.

By this driver, we can simplify arm_arch_timer drivers, and separate the ACPI GTDT knowledge from it.

Signed-off-by: Fu Wei fu.wei@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org Acked-by: Rafael J. Wysocki rafael.j.wysocki@intel.com

Acked-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com

Some nits below.

Great thanks!

...

Tested-by: Xiongfeng Wang wangxiongfeng2@huawei.com Reviewed-by: Hanjun Guo hanjun.guo@linaro.org Tested-by: Hanjun Guo hanjun.guo@linaro.org

---

arch/arm64/Kconfig | 1 + drivers/acpi/arm64/Kconfig | 3 + drivers/acpi/arm64/Makefile | 1 + drivers/acpi/arm64/gtdt.c | 157 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/acpi.h | 6 ++ 5 files changed, 168 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 3741859..7e2baec 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -2,6 +2,7 @@ config ARM64 def_bool y select ACPI_CCA_REQUIRED if ACPI select ACPI_GENERIC_GSI if ACPI

• select ACPI_GTDT if ACPI
  select ACPI_REDUCED_HARDWARE_ONLY if ACPI
  select ACPI_MCFG if ACPI
  select ACPI_SPCR_TABLE if ACPI
  

diff --git a/drivers/acpi/arm64/Kconfig b/drivers/acpi/arm64/Kconfig index 4616da4..5a6f80f 100644 --- a/drivers/acpi/arm64/Kconfig +++ b/drivers/acpi/arm64/Kconfig @@ -4,3 +4,6 @@

config ACPI_IORT bool

+config ACPI_GTDT

• bool
  

diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile index 72331f2..1017def 100644 --- a/drivers/acpi/arm64/Makefile +++ b/drivers/acpi/arm64/Makefile @@ -1 +1,2 @@ obj-$(CONFIG_ACPI_IORT) += iort.o +obj-$(CONFIG_ACPI_GTDT) += gtdt.o diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c new file mode 100644 index 0000000..8a03b4b --- /dev/null +++ b/drivers/acpi/arm64/gtdt.c @@ -0,0 +1,157 @@ +/*

• • ARM Specific GTDT table Support
• • Copyright (C) 2016, Linaro Ltd.
• • Author: Daniel Lezcano daniel.lezcano@linaro.org

• •     Fu Wei <fu.wei@linaro.org>
    

• •     Hanjun Guo <hanjun.guo@linaro.org>
    

• • This program is free software; you can redistribute it and/or modify
• • it under the terms of the GNU General Public License version 2 as
• • published by the Free Software Foundation.
• */

+#include <linux/acpi.h> +#include <linux/init.h> +#include <linux/kernel.h>

+#include <clocksource/arm_arch_timer.h>

+#undef pr_fmt +#define pr_fmt(fmt) "ACPI GTDT: " fmt

+/**

• • struct acpi_gtdt_descriptor - Store the key info of GTDT for all functions
• • @gtdt: The pointer to the struct acpi_table_gtdt of GTDT table.
• • @gtdt_end: The pointer to the end of GTDT table.
• • @platform_timer: The pointer to the start of Platform Timer Structure
• • The struct store the key info of GTDT table, it should be initialized by
• • acpi_gtdt_init.
• */

+struct acpi_gtdt_descriptor {

• struct acpi_table_gtdt *gtdt;
  

• void *gtdt_end;
  

• void *platform_timer;
  

+};

+static struct acpi_gtdt_descriptor acpi_gtdt_desc __initdata;

+static int __init map_gt_gsi(u32 interrupt, u32 flags) +{

• int trigger, polarity;
  

• trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
  

•                 : ACPI_LEVEL_SENSITIVE;
  

• polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
  

•                 : ACPI_ACTIVE_HIGH;
  

• return acpi_register_gsi(NULL, interrupt, trigger, polarity);
  

+}

+/**

• • acpi_gtdt_map_ppi() - Map the PPIs of per-cpu arch_timer.
• • @type: the type of PPI.
• • Note: Linux on arm64 isn't supported on the secure side.

Note: Secure state is not managed by the kernel on ARM64 systems.

Is that what you wanted to say ?

yes, you are right, thanks! :-) Will do so.

...

• • So we only handle the non-secure timer PPIs,
• • ARCH_TIMER_PHYS_SECURE_PPI is treated as invalid type.
• • Return: the mapped PPI value, 0 if error.
• */

+int __init acpi_gtdt_map_ppi(int type) +{

• struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;
  

• switch (type) {
  

• case ARCH_TIMER_PHYS_NONSECURE_PPI:
  

•         return map_gt_gsi(gtdt->non_secure_el1_interrupt,
  

•                           gtdt->non_secure_el1_flags);
  

• case ARCH_TIMER_VIRT_PPI:
  

•         return map_gt_gsi(gtdt->virtual_timer_interrupt,
  

•                           gtdt->virtual_timer_flags);
  

• case ARCH_TIMER_HYP_PPI:
  

•         return map_gt_gsi(gtdt->non_secure_el2_interrupt,
  

•                           gtdt->non_secure_el2_flags);
  

• default:
  

•         pr_err("Failed to map timer interrupt: invalid type.\n");
  

• }
  

• return 0;
  

+}

+/**

• • acpi_gtdt_c3stop() - Got c3stop info from GTDT according to the type of PPI.
• • @type: the type of PPI.
• • Return: 1 if the timer can be in deep idle state, 0 otherwise.

Return: true if the timer HW state is lost when a CPU enters an idle state, false otherwise

Thanks , will do

...

• */

+bool __init acpi_gtdt_c3stop(int type) +{

• struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;
  

• switch (type) {
  

• case ARCH_TIMER_PHYS_NONSECURE_PPI:
  

•         return !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON);
  

• case ARCH_TIMER_VIRT_PPI:
  

•         return !(gtdt->virtual_timer_flags & ACPI_GTDT_ALWAYS_ON);
  

• case ARCH_TIMER_HYP_PPI:
  

•         return !(gtdt->non_secure_el2_flags & ACPI_GTDT_ALWAYS_ON);
  

• default:
  

•         pr_err("Failed to get c3stop info: invalid type.\n");
  

• }
  

• return 0;
  

+}

+/**

• • acpi_gtdt_init() - Get the info of GTDT table to prepare for further init.
• • @table: The pointer to GTDT table.
• • @platform_timer_count: The pointer of int variate for returning the

I do not understand what this means.

...

• •                       number of platform timers. It can be NULL, if
    

• •                       driver don't need this info.
    

driver doesn't

Sorry, this is not clear, I will fix it by :

* @platform_timer_count: It points to a integer variable which is used * for storing the number of platform timers. * This pointer could be NULL, if the caller * doesn't need this info.

...

• • Return: 0 if success, -EINVAL if error.
• */

+int __init acpi_gtdt_init(struct acpi_table_header *table,

•                   int *platform_timer_count)
  

+{

• int ret = 0;
  

• int timer_count = 0;
  

• void *platform_timer = NULL;
  

• struct acpi_table_gtdt *gtdt;
  

• gtdt = container_of(table, struct acpi_table_gtdt, header);
  

• acpi_gtdt_desc.gtdt = gtdt;
  

• acpi_gtdt_desc.gtdt_end = (void *)table + table->length;
  

• if (table->revision < 2)
  

•         pr_warn("Revision:%d doesn't support Platform Timers.\n",
  

•                 table->revision);
  

Ok, two points here. First, I am not sure why you should warn if the table revision is < 2, is that a FW bug ? I do not think it is, you can just return 0.

I used pr_debug here before v20, then I got Hanjun's suggestion: ------- GTDT table revision is updated to 2 in ACPI 5.1, we will not support ACPI version under 5.1 and disable ACPI in FADT parse before this code is called, so if we get revision <2 here, I think we need to print warning (we need to keep the firmware stick to the spec on ARM64). ------- https://lkml.org/lkml/2017/1/19/82

So I started to use pr_warn.

...

• else if (!gtdt->platform_timer_count)
  

•         pr_debug("No Platform Timer.\n");
  

Ditto. Why keep executing ? There is nothing to do, just bail out with a return 0.

...

• else
  

•         timer_count = gtdt->platform_timer_count;
  

• if (timer_count) {
  

•         platform_timer = (void *)gtdt + gtdt->platform_timer_offset;
  

•         if (platform_timer < (void *)table +
  

•                              sizeof(struct acpi_table_gtdt)) {
  

•                 pr_err(FW_BUG "invalid timer data.\n");
  

•                 timer_count = 0;
  

•                 platform_timer = NULL;
  

•         ret = -EINVAL;
  

Same here, I suspect you want to consolidate the return path (I missed previous rounds of reviews so you should not worry too much, I can clean this up later) but to me a:

return -EINVAL;

would just do.

yes, you are right, I try to consolidate the return path. :-) It may can return earlier, let me try.

Lorenzo

...

•         }
  

• }
  

• acpi_gtdt_desc.platform_timer = platform_timer;
  

• if (platform_timer_count)
  

•         *platform_timer_count = timer_count;
  

• return ret;
  

+} diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 9b05886..4b5c146 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -595,6 +595,12 @@ enum acpi_reconfig_event { int acpi_reconfig_notifier_register(struct notifier_block *nb); int acpi_reconfig_notifier_unregister(struct notifier_block *nb);

+#ifdef CONFIG_ACPI_GTDT +int acpi_gtdt_init(struct acpi_table_header *table, int *platform_timer_count); +int acpi_gtdt_map_ppi(int type); +bool acpi_gtdt_c3stop(int type); +#endif

#else /* !CONFIG_ACPI */

#define acpi_disabled 1

2.9.3

Hi Lorenzo,

On 28 March 2017 at 19:35, Lorenzo Pieralisi lorenzo.pieralisi@arm.com wrote:

On Wed, Mar 22, 2017 at 12:31:18AM +0800, fu.wei@linaro.org wrote:

...

From: Fu Wei fu.wei@linaro.org

This patch adds support for parsing arch timer info in GTDT, provides some kernel APIs to parse all the PPIs and always-on info in GTDT and export them.

By this driver, we can simplify arm_arch_timer drivers, and separate the ACPI GTDT knowledge from it.

Signed-off-by: Fu Wei fu.wei@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org Acked-by: Rafael J. Wysocki rafael.j.wysocki@intel.com

Acked-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com

Some nits below.

...

Tested-by: Xiongfeng Wang wangxiongfeng2@huawei.com Reviewed-by: Hanjun Guo hanjun.guo@linaro.org Tested-by: Hanjun Guo hanjun.guo@linaro.org

---

arch/arm64/Kconfig | 1 + drivers/acpi/arm64/Kconfig | 3 + drivers/acpi/arm64/Makefile | 1 + drivers/acpi/arm64/gtdt.c | 157 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/acpi.h | 6 ++ 5 files changed, 168 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 3741859..7e2baec 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -2,6 +2,7 @@ config ARM64 def_bool y select ACPI_CCA_REQUIRED if ACPI select ACPI_GENERIC_GSI if ACPI

• select ACPI_GTDT if ACPI
  select ACPI_REDUCED_HARDWARE_ONLY if ACPI
  select ACPI_MCFG if ACPI
  select ACPI_SPCR_TABLE if ACPI
  

diff --git a/drivers/acpi/arm64/Kconfig b/drivers/acpi/arm64/Kconfig index 4616da4..5a6f80f 100644 --- a/drivers/acpi/arm64/Kconfig +++ b/drivers/acpi/arm64/Kconfig @@ -4,3 +4,6 @@

config ACPI_IORT bool

+config ACPI_GTDT

• bool
  

diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile index 72331f2..1017def 100644 --- a/drivers/acpi/arm64/Makefile +++ b/drivers/acpi/arm64/Makefile @@ -1 +1,2 @@ obj-$(CONFIG_ACPI_IORT) += iort.o +obj-$(CONFIG_ACPI_GTDT) += gtdt.o diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c new file mode 100644 index 0000000..8a03b4b --- /dev/null +++ b/drivers/acpi/arm64/gtdt.c @@ -0,0 +1,157 @@ +/*

• • ARM Specific GTDT table Support
• • Copyright (C) 2016, Linaro Ltd.
• • Author: Daniel Lezcano daniel.lezcano@linaro.org

• •     Fu Wei <fu.wei@linaro.org>
    

• •     Hanjun Guo <hanjun.guo@linaro.org>
    

• • This program is free software; you can redistribute it and/or modify
• • it under the terms of the GNU General Public License version 2 as
• • published by the Free Software Foundation.
• */

+#include <linux/acpi.h> +#include <linux/init.h> +#include <linux/kernel.h>

+#include <clocksource/arm_arch_timer.h>

+#undef pr_fmt +#define pr_fmt(fmt) "ACPI GTDT: " fmt

+/**

• • struct acpi_gtdt_descriptor - Store the key info of GTDT for all functions
• • @gtdt: The pointer to the struct acpi_table_gtdt of GTDT table.
• • @gtdt_end: The pointer to the end of GTDT table.
• • @platform_timer: The pointer to the start of Platform Timer Structure
• • The struct store the key info of GTDT table, it should be initialized by
• • acpi_gtdt_init.
• */

+struct acpi_gtdt_descriptor {

• struct acpi_table_gtdt *gtdt;
  

• void *gtdt_end;
  

• void *platform_timer;
  

+};

+static struct acpi_gtdt_descriptor acpi_gtdt_desc __initdata;

+static int __init map_gt_gsi(u32 interrupt, u32 flags) +{

• int trigger, polarity;
  

• trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
  

•                 : ACPI_LEVEL_SENSITIVE;
  

• polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
  

•                 : ACPI_ACTIVE_HIGH;
  

• return acpi_register_gsi(NULL, interrupt, trigger, polarity);
  

+}

+/**

• • acpi_gtdt_map_ppi() - Map the PPIs of per-cpu arch_timer.
• • @type: the type of PPI.
• • Note: Linux on arm64 isn't supported on the secure side.

Note: Secure state is not managed by the kernel on ARM64 systems.

Is that what you wanted to say ?

...

• • So we only handle the non-secure timer PPIs,
• • ARCH_TIMER_PHYS_SECURE_PPI is treated as invalid type.
• • Return: the mapped PPI value, 0 if error.
• */

+int __init acpi_gtdt_map_ppi(int type) +{

• struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;
  

• switch (type) {
  

• case ARCH_TIMER_PHYS_NONSECURE_PPI:
  

•         return map_gt_gsi(gtdt->non_secure_el1_interrupt,
  

•                           gtdt->non_secure_el1_flags);
  

• case ARCH_TIMER_VIRT_PPI:
  

•         return map_gt_gsi(gtdt->virtual_timer_interrupt,
  

•                           gtdt->virtual_timer_flags);
  

• case ARCH_TIMER_HYP_PPI:
  

•         return map_gt_gsi(gtdt->non_secure_el2_interrupt,
  

•                           gtdt->non_secure_el2_flags);
  

• default:
  

•         pr_err("Failed to map timer interrupt: invalid type.\n");
  

• }
  

• return 0;
  

+}

+/**

• • acpi_gtdt_c3stop() - Got c3stop info from GTDT according to the type of PPI.
• • @type: the type of PPI.
• • Return: 1 if the timer can be in deep idle state, 0 otherwise.

Return: true if the timer HW state is lost when a CPU enters an idle state, false otherwise

...

• */

+bool __init acpi_gtdt_c3stop(int type) +{

• struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;
  

• switch (type) {
  

• case ARCH_TIMER_PHYS_NONSECURE_PPI:
  

•         return !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON);
  

• case ARCH_TIMER_VIRT_PPI:
  

•         return !(gtdt->virtual_timer_flags & ACPI_GTDT_ALWAYS_ON);
  

• case ARCH_TIMER_HYP_PPI:
  

•         return !(gtdt->non_secure_el2_flags & ACPI_GTDT_ALWAYS_ON);
  

• default:
  

•         pr_err("Failed to get c3stop info: invalid type.\n");
  

• }
  

• return 0;
  

+}

+/**

• • acpi_gtdt_init() - Get the info of GTDT table to prepare for further init.
• • @table: The pointer to GTDT table.
• • @platform_timer_count: The pointer of int variate for returning the

I do not understand what this means.

...

• •                       number of platform timers. It can be NULL, if
    

• •                       driver don't need this info.
    

driver doesn't

...

• • Return: 0 if success, -EINVAL if error.
• */

+int __init acpi_gtdt_init(struct acpi_table_header *table,

•                   int *platform_timer_count)
  

+{

• int ret = 0;
  

• int timer_count = 0;
  

• void *platform_timer = NULL;
  

• struct acpi_table_gtdt *gtdt;
  

• gtdt = container_of(table, struct acpi_table_gtdt, header);
  

• acpi_gtdt_desc.gtdt = gtdt;
  

• acpi_gtdt_desc.gtdt_end = (void *)table + table->length;
  

• if (table->revision < 2)
  

•         pr_warn("Revision:%d doesn't support Platform Timers.\n",
  

•                 table->revision);
  

Ok, two points here. First, I am not sure why you should warn if the table revision is < 2, is that a FW bug ? I do not think it is, you can just return 0.

...

• else if (!gtdt->platform_timer_count)
  

•         pr_debug("No Platform Timer.\n");
  

Ditto. Why keep executing ? There is nothing to do, just bail out with a return 0.

...

• else
  

•         timer_count = gtdt->platform_timer_count;
  

• if (timer_count) {
  

•         platform_timer = (void *)gtdt + gtdt->platform_timer_offset;
  

•         if (platform_timer < (void *)table +
  

•                              sizeof(struct acpi_table_gtdt)) {
  

•                 pr_err(FW_BUG "invalid timer data.\n");
  

•                 timer_count = 0;
  

•                 platform_timer = NULL;
  

•         ret = -EINVAL;
  

Same here, I suspect you want to consolidate the return path (I missed previous rounds of reviews so you should not worry too much, I can clean this up later) but to me a:

return -EINVAL;

would just do.

For this problem, Can I do this:

/** * acpi_gtdt_init() - Get the info of GTDT table to prepare for further init. * @table: The pointer to GTDT table. * @platform_timer_count: It points to a integer variable which is used * for storing the number of platform timers. * This pointer could be NULL, if the caller * doesn't need this info. * * Return: 0 if success, -EINVAL if error. */ int __init acpi_gtdt_init(struct acpi_table_header *table, int *platform_timer_count) { void *platform_timer; struct acpi_table_gtdt *gtdt;

gtdt = container_of(table, struct acpi_table_gtdt, header); acpi_gtdt_desc.gtdt = gtdt; acpi_gtdt_desc.gtdt_end = (void *)table + table->length; acpi_gtdt_desc.platform_timer = NULL; if (platform_timer_count) *platform_timer_count = 0;

if (table->revision < 2) { pr_warn("Revision:%d doesn't support Platform Timers.\n", table->revision); return 0; }

if (!gtdt->platform_timer_count) { pr_debug("No Platform Timer.\n"); return 0; } if (platform_timer_count) *platform_timer_count = gtdt->platform_timer_count;

platform_timer = (void *)gtdt + gtdt->platform_timer_offset; if (platform_timer < (void *)table + sizeof(struct acpi_table_gtdt)) { pr_err(FW_BUG "invalid timer data.\n"); return -EINVAL; } acpi_gtdt_desc.platform_timer = platform_timer;

return 0; }

Lorenzo

...

•         }
  

• }
  

• acpi_gtdt_desc.platform_timer = platform_timer;
  

• if (platform_timer_count)
  

•         *platform_timer_count = timer_count;
  

• return ret;
  

+} diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 9b05886..4b5c146 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -595,6 +595,12 @@ enum acpi_reconfig_event { int acpi_reconfig_notifier_register(struct notifier_block *nb); int acpi_reconfig_notifier_unregister(struct notifier_block *nb);

+#ifdef CONFIG_ACPI_GTDT +int acpi_gtdt_init(struct acpi_table_header *table, int *platform_timer_count); +int acpi_gtdt_map_ppi(int type); +bool acpi_gtdt_c3stop(int type); +#endif

#else /* !CONFIG_ACPI */

#define acpi_disabled 1

2.9.3

On Wed, Mar 29, 2017 at 10:31:42PM +0800, Fu Wei wrote:

On 29 March 2017 at 22:29, Fu Wei fu.wei@linaro.org wrote:

...

Hi Lorenzo,

On 28 March 2017 at 19:35, Lorenzo Pieralisi lorenzo.pieralisi@arm.com wrote:

...

On Wed, Mar 22, 2017 at 12:31:18AM +0800, fu.wei@linaro.org wrote:

...

From: Fu Wei fu.wei@linaro.org

This patch adds support for parsing arch timer info in GTDT, provides some kernel APIs to parse all the PPIs and always-on info in GTDT and export them.

By this driver, we can simplify arm_arch_timer drivers, and separate the ACPI GTDT knowledge from it.

Signed-off-by: Fu Wei fu.wei@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org Acked-by: Rafael J. Wysocki rafael.j.wysocki@intel.com

Acked-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com

Some nits below.

...

Tested-by: Xiongfeng Wang wangxiongfeng2@huawei.com Reviewed-by: Hanjun Guo hanjun.guo@linaro.org Tested-by: Hanjun Guo hanjun.guo@linaro.org

---

arch/arm64/Kconfig | 1 + drivers/acpi/arm64/Kconfig | 3 + drivers/acpi/arm64/Makefile | 1 + drivers/acpi/arm64/gtdt.c | 157 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/acpi.h | 6 ++ 5 files changed, 168 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 3741859..7e2baec 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -2,6 +2,7 @@ config ARM64 def_bool y select ACPI_CCA_REQUIRED if ACPI select ACPI_GENERIC_GSI if ACPI

• select ACPI_GTDT if ACPI
  select ACPI_REDUCED_HARDWARE_ONLY if ACPI
  select ACPI_MCFG if ACPI
  select ACPI_SPCR_TABLE if ACPI
  

diff --git a/drivers/acpi/arm64/Kconfig b/drivers/acpi/arm64/Kconfig index 4616da4..5a6f80f 100644 --- a/drivers/acpi/arm64/Kconfig +++ b/drivers/acpi/arm64/Kconfig @@ -4,3 +4,6 @@

config ACPI_IORT bool

+config ACPI_GTDT

• bool
  

diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile index 72331f2..1017def 100644 --- a/drivers/acpi/arm64/Makefile +++ b/drivers/acpi/arm64/Makefile @@ -1 +1,2 @@ obj-$(CONFIG_ACPI_IORT) += iort.o +obj-$(CONFIG_ACPI_GTDT) += gtdt.o diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c new file mode 100644 index 0000000..8a03b4b --- /dev/null +++ b/drivers/acpi/arm64/gtdt.c @@ -0,0 +1,157 @@ +/*

• • ARM Specific GTDT table Support
• • Copyright (C) 2016, Linaro Ltd.
• • Author: Daniel Lezcano daniel.lezcano@linaro.org

• •     Fu Wei <fu.wei@linaro.org>
    

• •     Hanjun Guo <hanjun.guo@linaro.org>
    

• • This program is free software; you can redistribute it and/or modify
• • it under the terms of the GNU General Public License version 2 as
• • published by the Free Software Foundation.
• */

+#include <linux/acpi.h> +#include <linux/init.h> +#include <linux/kernel.h>

+#include <clocksource/arm_arch_timer.h>

+#undef pr_fmt +#define pr_fmt(fmt) "ACPI GTDT: " fmt

+/**

• • struct acpi_gtdt_descriptor - Store the key info of GTDT for all functions
• • @gtdt: The pointer to the struct acpi_table_gtdt of GTDT table.
• • @gtdt_end: The pointer to the end of GTDT table.
• • @platform_timer: The pointer to the start of Platform Timer Structure
• • The struct store the key info of GTDT table, it should be initialized by
• • acpi_gtdt_init.
• */

+struct acpi_gtdt_descriptor {

• struct acpi_table_gtdt *gtdt;
  

• void *gtdt_end;
  

• void *platform_timer;
  

+};

+static struct acpi_gtdt_descriptor acpi_gtdt_desc __initdata;

+static int __init map_gt_gsi(u32 interrupt, u32 flags) +{

• int trigger, polarity;
  

• trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
  

•                 : ACPI_LEVEL_SENSITIVE;
  

• polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
  

•                 : ACPI_ACTIVE_HIGH;
  

• return acpi_register_gsi(NULL, interrupt, trigger, polarity);
  

+}

+/**

• • acpi_gtdt_map_ppi() - Map the PPIs of per-cpu arch_timer.
• • @type: the type of PPI.
• • Note: Linux on arm64 isn't supported on the secure side.

Note: Secure state is not managed by the kernel on ARM64 systems.

Is that what you wanted to say ?

...

• • So we only handle the non-secure timer PPIs,
• • ARCH_TIMER_PHYS_SECURE_PPI is treated as invalid type.
• • Return: the mapped PPI value, 0 if error.
• */

+int __init acpi_gtdt_map_ppi(int type) +{

• struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;
  

• switch (type) {
  

• case ARCH_TIMER_PHYS_NONSECURE_PPI:
  

•         return map_gt_gsi(gtdt->non_secure_el1_interrupt,
  

•                           gtdt->non_secure_el1_flags);
  

• case ARCH_TIMER_VIRT_PPI:
  

•         return map_gt_gsi(gtdt->virtual_timer_interrupt,
  

•                           gtdt->virtual_timer_flags);
  

• case ARCH_TIMER_HYP_PPI:
  

•         return map_gt_gsi(gtdt->non_secure_el2_interrupt,
  

•                           gtdt->non_secure_el2_flags);
  

• default:
  

•         pr_err("Failed to map timer interrupt: invalid type.\n");
  

• }
  

• return 0;
  

+}

+/**

• • acpi_gtdt_c3stop() - Got c3stop info from GTDT according to the type of PPI.
• • @type: the type of PPI.
• • Return: 1 if the timer can be in deep idle state, 0 otherwise.

Return: true if the timer HW state is lost when a CPU enters an idle state, false otherwise

...

• */

+bool __init acpi_gtdt_c3stop(int type) +{

• struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;
  

• switch (type) {
  

• case ARCH_TIMER_PHYS_NONSECURE_PPI:
  

•         return !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON);
  

• case ARCH_TIMER_VIRT_PPI:
  

•         return !(gtdt->virtual_timer_flags & ACPI_GTDT_ALWAYS_ON);
  

• case ARCH_TIMER_HYP_PPI:
  

•         return !(gtdt->non_secure_el2_flags & ACPI_GTDT_ALWAYS_ON);
  

• default:
  

•         pr_err("Failed to get c3stop info: invalid type.\n");
  

• }
  

• return 0;
  

+}

+/**

• • acpi_gtdt_init() - Get the info of GTDT table to prepare for further init.
• • @table: The pointer to GTDT table.
• • @platform_timer_count: The pointer of int variate for returning the

I do not understand what this means.

...

• •                       number of platform timers. It can be NULL, if
    

• •                       driver don't need this info.
    

driver doesn't

...

• • Return: 0 if success, -EINVAL if error.
• */

+int __init acpi_gtdt_init(struct acpi_table_header *table,

•                   int *platform_timer_count)
  

+{

• int ret = 0;
  

• int timer_count = 0;
  

• void *platform_timer = NULL;
  

• struct acpi_table_gtdt *gtdt;
  

• gtdt = container_of(table, struct acpi_table_gtdt, header);
  

• acpi_gtdt_desc.gtdt = gtdt;
  

• acpi_gtdt_desc.gtdt_end = (void *)table + table->length;
  

• if (table->revision < 2)
  

•         pr_warn("Revision:%d doesn't support Platform Timers.\n",
  

•                 table->revision);
  

Ok, two points here. First, I am not sure why you should warn if the table revision is < 2, is that a FW bug ? I do not think it is, you can just return 0.

...

• else if (!gtdt->platform_timer_count)
  

•         pr_debug("No Platform Timer.\n");
  

Ditto. Why keep executing ? There is nothing to do, just bail out with a return 0.

...

• else
  

•         timer_count = gtdt->platform_timer_count;
  

• if (timer_count) {
  

•         platform_timer = (void *)gtdt + gtdt->platform_timer_offset;
  

•         if (platform_timer < (void *)table +
  

•                              sizeof(struct acpi_table_gtdt)) {
  

•                 pr_err(FW_BUG "invalid timer data.\n");
  

•                 timer_count = 0;
  

•                 platform_timer = NULL;
  

•         ret = -EINVAL;
  

Same here, I suspect you want to consolidate the return path (I missed previous rounds of reviews so you should not worry too much, I can clean this up later) but to me a:

return -EINVAL;

would just do.

For this problem, Can I do this:

/**

• acpi_gtdt_init() - Get the info of GTDT table to prepare for further init.
• @table: The pointer to GTDT table.
• @platform_timer_count: It points to a integer variable which is used

•                            for storing the number of platform timers.
  

•                            This pointer could be NULL, if the caller
  

•                            doesn't need this info.
  

• Return: 0 if success, -EINVAL if error.

*/ int __init acpi_gtdt_init(struct acpi_table_header *table, int *platform_timer_count) { void *platform_timer; struct acpi_table_gtdt *gtdt;

    gtdt = container_of(table, struct acpi_table_gtdt, header);
    acpi_gtdt_desc.gtdt = gtdt;
    acpi_gtdt_desc.gtdt_end = (void *)table + table->length;
    acpi_gtdt_desc.platform_timer = NULL;
    if (platform_timer_count)
            *platform_timer_count = 0;

    if (table->revision < 2) {
            pr_warn("Revision:%d doesn't support Platform Timers.\n",
                    table->revision);
            return 0;
    }

    if (!gtdt->platform_timer_count) {
            pr_debug("No Platform Timer.\n");
            return 0;
    }
    if (platform_timer_count)
            *platform_timer_count = gtdt->platform_timer_count;

sorry , this should be moved,

...

    platform_timer = (void *)gtdt + gtdt->platform_timer_offset;
    if (platform_timer < (void *)table + sizeof(struct acpi_table_gtdt)) {
            pr_err(FW_BUG "invalid timer data.\n");
            return -EINVAL;
    }
    acpi_gtdt_desc.platform_timer = platform_timer;

     if (platform_timer_count)
             *platform_timer_count = gtdt->platform_timer_count;

Here is the right place

Ok, to avoid adding bugs to code that has been tested already keep the current function version (as of v22) and send me a patch to clean this up at -rc1.

Multiple calls to acpi_gtdt_init() were my main concern.

Thanks, Lorenzo

...

    return 0;

}

...

Lorenzo

...

•         }
  

• }
  

• acpi_gtdt_desc.platform_timer = platform_timer;
  

• if (platform_timer_count)
  

•         *platform_timer_count = timer_count;
  

• return ret;
  

+} diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 9b05886..4b5c146 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -595,6 +595,12 @@ enum acpi_reconfig_event { int acpi_reconfig_notifier_register(struct notifier_block *nb); int acpi_reconfig_notifier_unregister(struct notifier_block *nb);

+#ifdef CONFIG_ACPI_GTDT +int acpi_gtdt_init(struct acpi_table_header *table, int *platform_timer_count); +int acpi_gtdt_map_ppi(int type); +bool acpi_gtdt_c3stop(int type); +#endif

#else /* !CONFIG_ACPI */

#define acpi_disabled 1

2.9.3

-- Best regards,

Fu Wei Software Engineer Red Hat

-- Best regards,

Fu Wei Software Engineer Red Hat

Hi Lorenzo,

On 30 March 2017 at 00:47, Lorenzo Pieralisi lorenzo.pieralisi@arm.com wrote:

On Wed, Mar 22, 2017 at 12:31:20AM +0800, fu.wei@linaro.org wrote:

...

From: Fu Wei fu.wei@linaro.org

On platforms booting with ACPI, architected memory-mapped timers' configuration data is provided by firmware through the ACPI GTDT static table.

The clocksource architected timer kernel driver requires a firmware interface to collect timer configuration and configure its driver. this infrastructure is present for device tree systems, but it is missing on systems booting with ACPI.

Implement the kernel infrastructure required to parse the static ACPI GTDT table so that the architected timer clocksource driver can make use of it on systems booting with ACPI, therefore enabling the corresponding timers configuration.

Signed-off-by: Fu Wei fu.wei@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org

---

drivers/acpi/arm64/gtdt.c | 130 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/acpi.h | 1 + 2 files changed, 131 insertions(+)

diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c index 8a03b4b..f471873 100644 --- a/drivers/acpi/arm64/gtdt.c +++ b/drivers/acpi/arm64/gtdt.c @@ -37,6 +37,28 @@ struct acpi_gtdt_descriptor {

static struct acpi_gtdt_descriptor acpi_gtdt_desc __initdata;

+static inline void *next_platform_timer(void *platform_timer) +{

• struct acpi_gtdt_header *gh = platform_timer;
  

• platform_timer += gh->length;
  

• if (platform_timer < acpi_gtdt_desc.gtdt_end)
  

•         return platform_timer;
  

• return NULL;
  

+}

+#define for_each_platform_timer(_g) \

• for (_g = acpi_gtdt_desc.platform_timer; _g;    \
  

•      _g = next_platform_timer(_g))
  

+static inline bool is_timer_block(void *platform_timer) +{

• struct acpi_gtdt_header *gh = platform_timer;
  

• return gh->type == ACPI_GTDT_TYPE_TIMER_BLOCK;
  

+}

static int __init map_gt_gsi(u32 interrupt, u32 flags) { int trigger, polarity; @@ -155,3 +177,111 @@ int __init acpi_gtdt_init(struct acpi_table_header *table,

  return ret;

}

+static int __init gtdt_parse_timer_block(struct acpi_gtdt_timer_block *block,

•                                  struct arch_timer_mem *timer_mem)
  

+{

• int i, j;
  

• struct acpi_gtdt_timer_entry *gtdt_frame;
  

• if (!block->timer_count) {
  

•         pr_err(FW_BUG "GT block present, but frame count is zero.");
  

•         return -ENODEV;
  

• }
  

• if (block->timer_count > ARCH_TIMER_MEM_MAX_FRAMES) {
  

•         pr_err(FW_BUG "GT block lists %d frames, ACPI spec only allows 8\n",
  

•                block->timer_count);
  

•         return -EINVAL;
  

• }
  

• timer_mem->cntctlbase = (phys_addr_t)block->block_address;
  

• /*
  

•  * The CNTCTLBase frame is 4KB (register offsets 0x000 - 0xFFC).
  

•  * See ARM DDI 0487A.k_iss10775, page I1-5129, Table I1-3
  

•  * "CNTCTLBase memory map".
  

•  */
  

• timer_mem->size = SZ_4K;
  

• gtdt_frame = (void *)block + block->timer_offset;
  

• if (gtdt_frame + block->timer_count != (void *)block + block->header.length)
  

•         return -EINVAL;
  

• /*
  

•  * Get the GT timer Frame data for every GT Block Timer
  

•  */
  

• for (i = 0, j = 0; i < block->timer_count; i++, gtdt_frame++) {
  

•         struct arch_timer_mem_frame *frame = &timer_mem->frame[j];
  

•         if (gtdt_frame->common_flags & ACPI_GTDT_GT_IS_SECURE_TIMER)
  

•                 continue;
  

•         if (!gtdt_frame->base_address || !gtdt_frame->timer_interrupt)
  

•                 return -EINVAL;
  

•         frame->phys_irq = map_gt_gsi(gtdt_frame->timer_interrupt,
  

•                                      gtdt_frame->timer_flags);
  

•         if (frame->phys_irq <= 0) {
  

•                 pr_warn("failed to map physical timer irq in frame %d.\n",
  

•                         i);
  

•                 return -EINVAL;
  

•         }
  

•         frame->virt_irq =
  

•                 map_gt_gsi(gtdt_frame->virtual_timer_interrupt,
  

•                            gtdt_frame->virtual_timer_flags);
  

•         if (frame->virt_irq <= 0) {
  

•                 pr_warn("failed to map virtual timer irq in frame %d.\n",
  

•                         i);
  

•                 acpi_unregister_gsi(gtdt_frame->timer_interrupt);
  

•                 return -EINVAL;
  

•         }
  

•         frame->frame_nr = gtdt_frame->frame_number;
  

•         frame->cntbase = gtdt_frame->base_address;
  

•         /*
  

•          * The CNTBaseN frame is 4KB (register offsets 0x000 - 0xFFC).
  

•          * See ARM DDI 0487A.k_iss10775, page I1-5130, Table I1-4
  

•          * "CNTBaseN memory map".
  

•          */
  

•         frame->size = SZ_4K;
  

•         j++;
  

• }
  

• timer_mem->num_frames = j;
  

• return 0;
  

+}

+/**

• • acpi_arch_timer_mem_init() - Get the info of all GT blocks in GTDT table.
• • @timer_mem: the pointer to the array of struct arch_timer_mem for returning

• •       the result of parsing. The element number of this array should
    

• •       be platform_timer_count(the total number of platform timers).
    

• • @count: The pointer of int variate for returning the number of GT

• •       blocks we have parsed.
    

Nit: this comment was wrong on all the patches I reviewed :) must be some copy and paste.

Thanks ,

* @timer_count: It points to a integer variable which is used for storing the * number of GT blocks we have parsed.

Is that OK for you?

...

• • Return: 0 if success, -EINVAL/-ENODEV if error.
• */

+int __init acpi_arch_timer_mem_init(struct arch_timer_mem *timer_mem,

•                             int *timer_count)
  

+{

• int ret;
  

• void *platform_timer;
  

• *timer_count = 0;
  

• for_each_platform_timer(platform_timer) {
  

•         if (is_timer_block(platform_timer)) {
  

•                 ret = gtdt_parse_timer_block(platform_timer, timer_mem);
  

•                 if (ret)
  

•                         return ret;
  

Isn't there some unwinding to carry out here (eg GSI) ?

Thanks for your reminding, it should be in gtdt_parse_timer_block, will do

Otherwise it looks fine (minus Mark's request for using frame numbers as indexes that you should change).

Lorenzo

...

•                 timer_mem++;
  

•                 (*timer_count)++;
  

•         }
  

• }
  

• if (*timer_count)
  

•         pr_info("found %d memory-mapped timer block(s).\n",
  

•                 *timer_count);
  

• return 0;
  

+} diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 4b5c146..3193724 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -599,6 +599,7 @@ int acpi_reconfig_notifier_unregister(struct notifier_block *nb); int acpi_gtdt_init(struct acpi_table_header *table, int *platform_timer_count); int acpi_gtdt_map_ppi(int type); bool acpi_gtdt_c3stop(int type); +int acpi_arch_timer_mem_init(struct arch_timer_mem *timer_mem, int *timer_count); #endif

#else /* !CONFIG_ACPI */

2.9.3

Hi Lorenzo,

On 28 March 2017 at 23:41, Lorenzo Pieralisi lorenzo.pieralisi@arm.com wrote:

On Wed, Mar 22, 2017 at 12:31:22AM +0800, fu.wei@linaro.org wrote:

...

From: Fu Wei fu.wei@linaro.org

This driver adds support for parsing SBSA Generic Watchdog timer in GTDT, parse all info in SBSA Generic Watchdog Structure in GTDT, and creating a platform device with that information.

This allows the operating system to obtain device data from the resource of platform device. The platform device named "sbsa-gwdt" can be used by the ARM SBSA Generic Watchdog driver.

Signed-off-by: Fu Wei fu.wei@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org Tested-by: Xiongfeng Wang wangxiongfeng2@huawei.com

---

drivers/acpi/arm64/gtdt.c | 94 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 94 insertions(+)

diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c index f471873..5d167f0 100644 --- a/drivers/acpi/arm64/gtdt.c +++ b/drivers/acpi/arm64/gtdt.c @@ -14,6 +14,7 @@ #include <linux/acpi.h> #include <linux/init.h> #include <linux/kernel.h> +#include <linux/platform_device.h>

#include <clocksource/arm_arch_timer.h>

@@ -59,6 +60,17 @@ static inline bool is_timer_block(void *platform_timer) return gh->type == ACPI_GTDT_TYPE_TIMER_BLOCK; }

+static inline bool is_non_secure_watchdog(void *platform_timer) +{

• struct acpi_gtdt_header *gh = platform_timer;
  

• struct acpi_gtdt_watchdog *wd = platform_timer;
  

• if (gh->type != ACPI_GTDT_TYPE_WATCHDOG)
  

•         return false;
  

• return !(wd->timer_flags & ACPI_GTDT_WATCHDOG_SECURE);
  

+}

static int __init map_gt_gsi(u32 interrupt, u32 flags) { int trigger, polarity; @@ -285,3 +297,85 @@ int __init acpi_arch_timer_mem_init(struct arch_timer_mem *timer_mem,

  return 0;

}

+/*

• • Initialize a SBSA generic Watchdog platform device info from GTDT
• */

+static int __init gtdt_import_sbsa_gwdt(struct acpi_gtdt_watchdog *wd,

•                                 int index)
  

+{

• struct platform_device *pdev;
  

• int irq = map_gt_gsi(wd->timer_interrupt, wd->timer_flags);
  

• /*
  

•  * According to SBSA specification the size of refresh and control
  

•  * frames of SBSA Generic Watchdog is SZ_4K(Offset 0x000 – 0xFFF).
  

•  */
  

• struct resource res[] = {
  

•         DEFINE_RES_MEM(wd->control_frame_address, SZ_4K),
  

•         DEFINE_RES_MEM(wd->refresh_frame_address, SZ_4K),
  

•         DEFINE_RES_IRQ(irq),
  

• };
  

• int nr_res = ARRAY_SIZE(res);
  

• pr_debug("found a Watchdog (0x%llx/0x%llx gsi:%u flags:0x%x).\n",
  

•          wd->refresh_frame_address, wd->control_frame_address,
  

•          wd->timer_interrupt, wd->timer_flags);
  

• if (!(wd->refresh_frame_address && wd->control_frame_address)) {
  

•         pr_err(FW_BUG "failed to get the Watchdog base address.\n");
  

+ acpi_unregister_gsi(wd->timer_interrupt);

...

•         return -EINVAL;
  

You should unmap the gsi here.

yes, you are right, fixed it.

...

• }
  

• if (irq <= 0) {
  

•         pr_warn("failed to map the Watchdog interrupt.\n");
  

•         nr_res--;
  

• }
  

• /*
  

•  * Add a platform device named "sbsa-gwdt" to match the platform driver.
  

•  * "sbsa-gwdt": SBSA(Server Base System Architecture) Generic Watchdog
  

•  * The platform driver (like drivers/watchdog/sbsa_gwdt.c)can get device
  

+ * The platform driver can get device info below by matching this name.

Nit: I would not hardcode drivers paths in comments.

OK, deleted it

...

•  * info below by matching this name.
  

•  */
  

• pdev = platform_device_register_simple("sbsa-gwdt", index, res, nr_res);
  

• if (IS_ERR(pdev)) {
  

•         acpi_unregister_gsi(wd->timer_interrupt);
  

•         return PTR_ERR(pdev);
  

• }
  

• return 0;
  

+}

+static int __init gtdt_sbsa_gwdt_init(void) +{

• int ret, i = 0;
  

• void *platform_timer;
  

• struct acpi_table_header *table;
  

• if (acpi_disabled)
  

•         return 0;
  

• if (ACPI_FAILURE(acpi_get_table(ACPI_SIG_GTDT, 0, &table)))
  

•         return -EINVAL;
  

• ret = acpi_gtdt_init(table, NULL);
  

• if (ret)
  

•         return ret;
  

Ok, I missed previous versions reviews so I miss the background here and I apologise.

I do not understand why you call acpi_gtdt_init() again (or better, why acpi_gtdt_init() does not return straight away) here if the stashed pointer in acpi_gtdt_desc is already set. I am not a big fan of the for_each_platform_timer macro either, here you can just read the ACPI_SIG_GTDT and parse its entries, I see no point in calling acpi_gtdt_init() again, there is nothing to stash for later probing, is there ?

Or it is just to reuse common parsing code ? Regardless, if the acpi_gtdt_desc struct is already initialized acpi_gtdt_init() should just return or I am missing the point.

I would like clarifications on the acpi_gtdt_init() call above please (plus GSI unmap fix), apart from that:

Reviewed-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com

Actually, after the discussion in the 7th patch, I have tried to do this, see if that can make the code simpler. Then I found out that (1) If we would like to reuse "for_each_platform_timer" (and "next_platform_timer") to scan the GTDT for SBSA watchdog, we have to re-initialize acpi_gtdt_desc, too. So we still need to explain that why we have to re-initialize acpi_gtdt_desc. (2) If we totally ignore acpi_gtdt_desc, and acpi_gtdt_init(), we can't re-use "for_each_platform_timer" (and "next_platform_timer") . we have to re-write the loop of scanning the GTDT for SBSA watchdog,

So may I suggest that maybe we can keep using acpi_gtdt_init, only add the comment to explain why we have to re-initialize acpi_gtdt_desc(Just what you have said in the 7th patch. Thanks for your correction for the comment, I will use that ), this way maybe can make the code simpler.

But If you still concern about this, we still can discuss this at -rc1.

Great thanks for your help! :-)

...

• for_each_platform_timer(platform_timer) {
  

•         if (is_non_secure_watchdog(platform_timer)) {
  

•                 ret = gtdt_import_sbsa_gwdt(platform_timer, i);
  

•                 if (ret)
  

•                         break;
  

•                 i++;
  

•         }
  

• }
  

• if (i)
  

•         pr_info("found %d SBSA generic Watchdog(s).\n", i);
  

• return ret;
  

+}

+device_initcall(gtdt_sbsa_gwdt_init);

2.9.3