From: Fu Wei fu.wei@linaro.org
The patch add memory-mapped timer register support for arm_arch_timer driver by using the information provided by the new GTDT driver of ACPI.
Signed-off-by: Fu Wei fu.wei@linaro.org --- drivers/clocksource/arm_arch_timer.c | 136 +++++++++++++++++++++++++++++++++++ 1 file changed, 136 insertions(+)
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index db466d5..7e7604b 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -680,6 +680,15 @@ arch_timer_needs_probing(int type, const struct of_device_id *matches) needs_probing = true; of_node_put(dn);
+#ifdef CONFIG_ACPI_GTDT + /* + * Check if we have timer in GTDT table + */ + if (!acpi_disabled && gtdt_timer_is_available(type) && + !(arch_timers_present & type)) + needs_probing = true; +#endif + return needs_probing; }
@@ -874,4 +883,131 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *table) return 0; } CLOCKSOURCE_ACPI_DECLARE(arch_timer, ACPI_SIG_GTDT, arch_timer_acpi_init); + +static u32 __init arch_timer_mem_cnttidr(struct acpi_gtdt_timer_block *gt_block) +{ + phys_addr_t cntctlbase_phy; + void __iomem *cntctlbase; + u32 cnttidr; + + cntctlbase_phy = (phys_addr_t)gtdt_gt_cntctlbase(gt_block); + if (!cntctlbase_phy) { + pr_err("Can't find CNTCTLBase.\n"); + return 0; + } + + /* + * According to ARMv8 Architecture Reference Manual(ARM), + * the size of CNTCTLBase frame of memory-mapped timer + * is SZ_4K(Offset 0x000 – 0xFFF). + */ + cntctlbase = ioremap(cntctlbase_phy, SZ_4K); + if (!cntctlbase) { + pr_err("Can't map CNTCTLBase\n"); + return 0; + } + cnttidr = readl_relaxed(cntctlbase + CNTTIDR); + iounmap(cntctlbase); + + return cnttidr; +} + +static int __init arch_timer_mem_best_frame(struct acpi_table_header *table, + struct arch_timer_mem_data *data) +{ + struct acpi_gtdt_timer_block *gt_block; + u32 frame_number, timer_count, cnttidr; + int i; + + gt_block = gtdt_gt_block(table, 0); + if (!gt_block) { + pr_err("Can't find GT Block.\n"); + return -EINVAL; + } + + timer_count = gtdt_gt_timer_count(gt_block); + if (!timer_count) { + pr_err("Can't find GT frame number.\n"); + return -EINVAL; + } + + if (gtdt_gt_timer_data(gt_block, 0, false, data)) { + pr_err("Can't get first phy timer.\n"); + return -EINVAL; + } + + /* + * Get Generic Timer Counter-timer Timer ID Register + * for Virtual Timer Capability info + */ + cnttidr = arch_timer_mem_cnttidr(gt_block); + + /* + * Try to find a virtual capable frame. + * Otherwise fall back to the first physical capable frame. + */ + for (i = 0; i < timer_count; i++) { + frame_number = gtdt_gt_frame_number(gt_block, i); + if (frame_number < ARCH_TIMER_MEM_MAX_FRAME && + cnttidr & CNTTIDR_VIRT(frame_number)) { + if (!gtdt_gt_timer_data(gt_block, i, true, data)) { + arch_timer_mem_use_virtual = true; + return 0; + } + pr_warn("Can't get virt timer.\n"); + } + } + + return 0; +} + +/* Initialize memory-mapped timer(wake-up timer) */ +static int __init arch_timer_mem_acpi_init(struct acpi_table_header *table) +{ + struct arch_timer_mem_data data; + void __iomem *cntbase; + + if (arch_timers_present & ARCH_MEM_TIMER) { + pr_warn("memory-mapped timer already initialized, skipping\n"); + return -EINVAL; + } + arch_timers_present |= ARCH_MEM_TIMER; + + if (arch_timer_mem_best_frame(table, &data)) + return -EINVAL; + + /* + * According to ARMv8 Architecture Reference Manual(ARM), + * the size of CNTBaseN frames of memory-mapped timer + * is SZ_4K(Offset 0x000 – 0xFFF). + */ + cntbase = ioremap(data.cntbase_phy, SZ_4K); + if (!cntbase) { + pr_err("Can't map CntBase.\n"); + return -EINVAL; + } + arch_counter_base = cntbase; + + if (!data.irq) { + pr_err("Frame missing %s irq", + arch_timer_mem_use_virtual ? "virt" : "phys"); + return -EINVAL; + } + + /* + * Because in a system that implements both Secure and + * Non-secure states, CNTFRQ is only accessible in Secure state. + * So we try to get the system counter frequency from cntfrq_el0 + * (system coprocessor register) here just like arch_timer. + */ + arch_timer_detect_rate(NULL, NULL); + + arch_timer_mem_register(cntbase, data.irq); + arch_timer_common_init(); + + return 0; +} + +CLOCKSOURCE_ACPI_DECLARE(arch_timer_mem, ACPI_SIG_GTDT, + arch_timer_mem_acpi_init); #endif