Hi Daniel,
Thanks for review my patches. :-)
On 31 May 2016 at 06:56, Daniel Lezcano daniel.lezcano@linaro.org wrote:
On 05/24/2016 03:30 PM, fu.wei@linaro.org wrote:
From: Fu Wei fu.wei@linaro.org
This driver adds support for parsing all kinds of timer in GTDT: (1)arch timer: provide a kernel API to parse all the PPIs and always-on info in GTDT and export them by filling the structs which provided by parameters(pointer of them).
(2)memory-mapped timer: provide a kernel APIs to parse GT Block Structure in GTDT, export all the timer info by filling the struct which provided by parameter(pointer of the struct).
(3)SBSA Generic Watchdog: 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.
By this driver, we can simplify all the relevant drivers, and separate all the ACPI GTDT knowledge from them.
Signed-off-by: Fu Wei fu.wei@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org
Hi Fu Wei,
the code is better than the previous version but it is still confusing. There are global variables accessed several times by different functions and modified. This is an encapsulation issue.
This code is a bit hard to follow.
Please split it out into 4 patches:
- Create a clean base with helper functions and proper encapsulation for
gtdt.
Add gtdt timer based code
Add gtdt mem timer based code
Add gtdt watchdog based code
spliting the GTDT driver patch is a good idea, will do.
Comments below.
Thanks !
-- Daniel
drivers/acpi/Kconfig | 9 + drivers/acpi/Makefile | 1 + drivers/acpi/acpi_gtdt.c | 309 +++++++++++++++++++++++++++++++++++ include/clocksource/arm_arch_timer.h | 16 ++ include/linux/acpi.h | 6 + 5 files changed, 341 insertions(+)
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig index b7e2e77..27a5cf9 100644 --- a/drivers/acpi/Kconfig +++ b/drivers/acpi/Kconfig @@ -521,4 +521,13 @@ config XPOWER_PMIC_OPREGION
endif
+config ACPI_GTDT
bool "ACPI GTDT Support"depends on ARM64helpGTDT (Generic Timer Description Table) provides informationfor per-processor timers and Platform (memory-mapped) timersfor ARM platforms. Select this option to provide informationneeded for the timers init.Why not ARM64's Kconfig select ACPI_GTDT ?
This config option assumes an user will manually select this option which I believe it makes sense to have always on when ARM64=y. So why not create a silent option and select it directly from the ARM64 platform Kconfig ?
I use "depends on ARM64" here, because GTDT is only for ARM, and only ARM64 support ACPI. GTDT is meaningless for other architecture. This "depends on" just makes sure only ARM64 can select it.
But user don't need to manually select this option. Once ARM64=y and ACPI=y, this will be automatically selected, because we have this in [PATCH v5 5/6]:
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 47352d2..5a5baa1 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -8,6 +8,7 @@ config CLKSRC_OF config CLKSRC_ACPI bool select CLKSRC_PROBE + select ACPI_GTDT
config CLKSRC_PROBE bool
And CLKSRC_ACPI will be selected by below in Kconfig of clocksource(mainline kernel):
config ARM_ARCH_TIMER bool select CLKSRC_OF if OF select CLKSRC_ACPI if ACPI
And ARM_ARCH_TIMER will be selected by ARM64 in arch/arm64/Kconfig(mainline kernel).
So ARM64=y --> ARM_ARCH_TIMER=y (if ACPI=y) --> CLKSRC_ACPI=y --> ACPI_GTDT=y
I think that is the right solution. Do I miss something?
endif # ACPI
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile index 251ce85..848aa8a 100644 --- a/drivers/acpi/Makefile +++ b/drivers/acpi/Makefile @@ -99,5 +99,6 @@ obj-$(CONFIG_ACPI_EXTLOG) += acpi_extlog.o obj-$(CONFIG_PMIC_OPREGION) += pmic/intel_pmic.o obj-$(CONFIG_CRC_PMIC_OPREGION) += pmic/intel_pmic_crc.o obj-$(CONFIG_XPOWER_PMIC_OPREGION) += pmic/intel_pmic_xpower.o +obj-$(CONFIG_ACPI_GTDT) += acpi_gtdt.o
video-objs += acpi_video.o video_detect.o diff --git a/drivers/acpi/acpi_gtdt.c b/drivers/acpi/acpi_gtdt.c new file mode 100644 index 0000000..e54fadf --- /dev/null +++ b/drivers/acpi/acpi_gtdt.c @@ -0,0 +1,309 @@ +/*
- ARM Specific GTDT table Support
- Copyright (C) 2015, Linaro Ltd.
- Author: 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/device.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/platform_device.h>
+#include <clocksource/arm_arch_timer.h>
+#undef pr_fmt +#define pr_fmt(fmt) "GTDT: " fmt
+typedef int (*platform_timer_handler)(void *platform_timer, int index,
void *data);+static void *platform_timer_struct __initdata; +static u32 platform_timer_count __initdata; +static void *gtdt_end __initdata;
I am pretty sure you can get ride of these global variables with a little effort.
yes, I am also trying to get ride of these global variables. will try.
+static int __init for_platform_timer(enum acpi_gtdt_type type,
platform_timer_handler handler, void*data)
For the clarity of the code, I suggest to use a macro with a name similar to what we find in the kernel:
#define gtdt_for_each(type, ...) ... #define gtdt_for_each_timer gtdt_for_each(ACPI_GTDT_TYPE_TIMER_BLOCK) #define gtdt_for_each_wd gtdt_for_each(ACPI_GTDT_TYPE_WATCHDOG)
... and rework this function to clarify its purpose.
yes, that is a very good idea, thanks, will do.
What is for ? Count the number of 'type' which succeed to call the handler ?
because we need a index of watchdog timer for importing it into the resource of platform_device, but I think I can ues a static variable to solve this problem? Any thought?
+{
struct acpi_gtdt_header *header;int i, index, ret;void *platform_timer = platform_timer_struct;for (i = 0, index = 0; i < platform_timer_count; i++) {if (platform_timer > gtdt_end) {pr_err(FW_BUG "subtable pointer overflows.\n");platform_timer_count = i;Fix firmware bug in the kernel ? No. Up to the firmware to fix it, "no handy, no candy".
So you are suggesting that if we find this firmware bug, just return error instead of using the info in a problematic table, right?
break;
}header = (struct acpi_gtdt_header *)platform_timer;if (header->type == type) {ret = handler(platform_timer, index, data);if (ret)pr_err("failed to handler subtable%d.\n", i);
elseindex++;}platform_timer += header->length;That is not correct. This function is setting the platform_timer pointer to the end. Even if that works, it violates the encapsulation paradigm. Regarding how are used those global variables, please kill them and use proper parameter and structure encapsulation.
So let me explain this a little: "void *platform_timer = platform_timer_struct;" is getting the pointer of first Platform Timer Structure, platform_timer_struct in this patchset is a global variable, but platform_timer is a local variable in the for_platform_timer function.
Platform Timer Structure Field is a array of Platform Timer Type structures. And the length of each structure maybe different, so I think "platform_timer += header->length" is a right approach to move on to next Platform Timer structures
Do I misunderstand your comment? or maybe I miss something?
}
return index;+}
+/*
- Get some basic info from GTDT table, and init the global variables
above
- for all timers initialization of Generic Timer.
- This function does some validation on GTDT table, and will be run
only once.
- */
+static void __init platform_timer_init(struct acpi_table_header *table,
struct acpi_table_gtdt *gtdt)+{
gtdt_end = (void *)table + table->length;if (table->revision < 2) {pr_info("Revision:%d doesn't support Platform Timers.\n",table->revision);return;}This check should be called much sooner, before entering the gtdt subsystems. It is too late here.
the reason I check table revision here is that: the difference between revision 1 and 2 is revision-2 adds Platform Timer Structure support. and this init function is just for getting some basic Platform Timer info in "main" table. So at the beginning of this function I check the revision.
But it also makes sense to move this out to gtdt_arch_timer_init like this:
if (table->revision < 2) return 0; else platform_timer_init(table, gtdt);
Any suggestion??
platform_timer_count = gtdt->platform_timer_count;
if (!platform_timer_count) {pr_info("No Platform Timer structures.\n");return;}platform_timer_struct = (void *)gtdt +gtdt->platform_timer_offset;
if (platform_timer_struct < (void *)table +sizeof(struct acpi_table_gtdt)) {pr_err(FW_BUG "Platform Timer pointer error.\n");platform_timer_struct = NULL;platform_timer_count = 0;}Why this check ?
just make sure the pointer of first Platform Timer Structur we got is OK, or platform_timer_offset is right. But considering the suggestion you've given above, maybe I should just return error for the bad table.
+}
+static int __init map_generic_timer_interrupt(u32 interrupt, u32 flags) +{
int trigger, polarity;if (!interrupt)return 0;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);+}
+/*
- Get the necessary info of arch_timer from GTDT table.
- */
+int __init gtdt_arch_timer_init(struct acpi_table_header *table, int *ppi,
bool *c3stop, u32 *timer_count)+{
struct acpi_table_gtdt *gtdt;This API is not correctly separating both subsystems. Moving the code from the arch_arm_timer init function here is not the solution.
I suggest the following:
- Change CLOCKSOURCE_ACPI_DECLARE to pass the init function as:
int __init gtdt_init(struct acpi_table_gtdt *gtdt);
Add helpers:
int gtdt_map_irq(struct acpi_table_gtdt *gtdt, int flags);
I guess "int flags" is enum ppi_nr, right?
int gtdt_c3stop(struct acpi_table_gtdt *gtdt);
- Export these helpers
arch_arm_timer.c should see nothing more than:
struct acpi_table_gtdt;
- Use these helpers in the arch_arm_timer.c
static int __init arch_timer_acpi_init(struct acpi_table_gtdt *gtdt) { arch_timer_ppi[PHYS_SECURE_PPI] = gtdt_map_irq(gtdt, flags); arch_timer_ppi[PHYS_NONSECURE_PPI] = gtdt_map_irq(gtdt, flags); arch_timer_ppi[VIRT_PPI] = gtdt_map_irq(gtdt, flags); arch_timer_ppi[HYP_PPI] = gtdt_map_irq(gtdt, flags); arch_timer_c3stop = gtdt_c3stop(gtdt);
arch_timer_init(); return 0;}
this makes sense, will do this way.
if (acpi_disabled || !table || !ppi || !c3stop)
return -EINVAL;Why acpi_disabled is an error here but ok for gtdt_sbsa_gwdt_init() ?
It should return 0, too. Thanks for pointing it out. will fix it.
gtdt = container_of(table, struct acpi_table_gtdt, header);
if (!gtdt) {pr_err("table pointer error.\n");return -EINVAL;}ppi[PHYS_SECURE_PPI] =map_generic_timer_interrupt(gtdt->secure_el1_interrupt,gtdt->secure_el1_flags);ppi[PHYS_NONSECURE_PPI] =map_generic_timer_interrupt(gtdt->non_secure_el1_interrupt,
gtdt->non_secure_el1_flags);ppi[VIRT_PPI] =map_generic_timer_interrupt(gtdt->virtual_timer_interrupt,gtdt->virtual_timer_flags);ppi[HYP_PPI] =map_generic_timer_interrupt(gtdt->non_secure_el2_interrupt,
gtdt->non_secure_el2_flags);*c3stop = !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON);platform_timer_init(table, gtdt);if (timer_count)*timer_count = platform_timer_count;come on !
All right, will fix it by the suggestion you've given above.
return 0;+}
+/*
- Helper function for getting the pointer of a timer frame in GT block.
- */
+static void __init *gtdt_gt_timer_frame(struct acpi_gtdt_timer_block *gt_block,
int index)+{
void *timer_frame = (void *)gt_block + gt_block->timer_offset +sizeof(struct acpi_gtdt_timer_entry) * index;if (timer_frame <= (void *)gt_block + gt_block->header.length -sizeof(struct acpi_gtdt_timer_entry))return timer_frame;return NULL;+}
+static int __init gtdt_parse_gt_block(void *platform_timer, int index,
void *data)+{
struct acpi_gtdt_timer_block *block;struct acpi_gtdt_timer_entry *frame;struct gt_block_data *block_data;int i, j;if (!platform_timer || !data)return -EINVAL;block = platform_timer;block_data = data + sizeof(struct gt_block_data) * index;if (!block->block_address || !block->timer_count) {pr_err(FW_BUG "invalid GT Block data.\n");return -EINVAL;}block_data->cntctlbase_phy = (phys_addr_t)block->block_address;block_data->timer_count = block->timer_count;/** Get the GT timer Frame data for every GT Block Timer*/for (i = 0, j = 0; i < block->timer_count; i++) {frame = gtdt_gt_timer_frame(block, i);if (!frame || !frame->base_address ||!frame->timer_interrupt) {
pr_err(FW_BUG "invalid GT Block Timer data,skip.\n");
continue;}block_data->timer[j].frame_nr = frame->frame_number;block_data->timer[j].cntbase_phy = frame->base_address;block_data->timer[j].irq = map_generic_timer_interrupt(frame->timer_interrupt,frame->timer_flags);if (frame->virtual_timer_interrupt)block_data->timer[j].virt_irq =map_generic_timer_interrupt(frame->virtual_timer_interrupt,frame->virtual_timer_flags);j++;}if (j)return 0;block_data->cntctlbase_phy = (phys_addr_t)NULL;block_data->timer_count = 0;return -EINVAL;+}
+/*
- Get the GT block info for memory-mapped timer from GTDT table.
- Please make sure we have called gtdt_arch_timer_init, because it
helps to
- init the global variables.
- */
+int __init gtdt_arch_timer_mem_init(struct gt_block_data *data) +{
int ret = for_platform_timer(ACPI_GTDT_TYPE_TIMER_BLOCK,gtdt_parse_gt_block, (void *)data);(void *) explicit cast is not needed.
yes, you are right, will delete it.
pr_info("found %d memory-mapped timer block.\n", ret);
return ret;+}
+/*
- Initialize a SBSA generic Watchdog platform device info from GTDT
- */
+static int __init gtdt_import_sbsa_gwdt(void *platform_timer,
int index, void *data)+{
struct platform_device *pdev;struct acpi_gtdt_watchdog *wd = platform_timer;int irq = map_generic_timer_interrupt(wd->timer_interrupt,wd->timer_flags);int no_irq = 1;/** 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),};pr_debug("a Watchdog GT(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 getting the Watchdog GT frameaddr.\n");
return -EINVAL;}if (!wd->timer_interrupt)pr_warn(FW_BUG "failed getting the Watchdog GT GSIV.\n");else if (irq <= 0)pr_warn("failed to map the Watchdog GT GSIV.\n");elseno_irq = 0;/** Add a platform device named "sbsa-gwdt" to match the platformdriver.
* "sbsa-gwdt": SBSA(Server Base System Architecture) GenericWatchdog
* The platform driver (like drivers/watchdog/sbsa_gwdt.c)can getdevice
* info below by matching this name.*/pdev = platform_device_register_simple("sbsa-gwdt", index, res,ARRAY_SIZE(res) - no_irq);if (IS_ERR(pdev)) {acpi_unregister_gsi(wd->timer_interrupt);return PTR_ERR(pdev);}return 0;+}
+static int __init gtdt_sbsa_gwdt_init(void) +{
struct acpi_table_header *table;struct acpi_table_gtdt *gtdt;int ret;if (acpi_disabled)return 0;if (ACPI_FAILURE(acpi_get_table(ACPI_SIG_GTDT, 0, &table)))return -EINVAL;/* global variables initialization */gtdt_end = (void *)table + table->length;That is prone to bug. The end of the table is computed here and stored in the global variable and then computed again in platform_timer_init and also stored in the global variable.
Kill this global variable.
Actually this is not a bug, I mean to do this twice. Let me explain this:
when we initialize arch_timer and memory-mapped timer, we are in the very early stage of initialization, so we use bootmem at that time.
But the time we try to import SBSA watchdog info to the resource of platform_device is in " do_initcalls();", at that time we have already switched to slab. So the previous pointer can not be used again(mapping is changed), we have to map the table and get a new pointer.
gtdt = container_of(table, struct acpi_table_gtdt, header);
platform_timer_struct = (void *)gtdt +gtdt->platform_timer_offset;
ret = for_platform_timer(ACPI_GTDT_TYPE_WATCHDOG,gtdt_import_sbsa_gwdt, NULL);pr_info("found %d SBSA generic Watchdog.\n", ret);return 0;+}
+device_initcall(gtdt_sbsa_gwdt_init);
Do you really have to call device_initcall ?
I think so, because SBSA watchdog is a platform device, the driver get device info from the resource of platform_device. So I import the watchdog info from GTDT to the resource of platform_device here. That means we have to do this after "driver_init();", so I think device_initcall(will be called in do_initcalls();) makes sense
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