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Subject[PATCH v14 8/9] clocksource/drivers/arm_arch_timer: Add GTDT support for memory-mapped timer
Date
From: Fu Wei <fu.wei@linaro.org>

The patch add memory-mapped timer register support 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 | 92 +++++++++++++++++++++++++++++++++---
1 file changed, 85 insertions(+), 7 deletions(-)

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index e78095f..8482fba 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -660,6 +660,7 @@ out:
static int __init arch_timer_mem_register(struct device_node *np, void *frame)
{
struct device_node *frame_node = NULL;
+ struct gt_timer_data *frame_data = NULL;
struct arch_timer *t;
void __iomem *base;
irq_handler_t func;
@@ -678,8 +679,17 @@ static int __init arch_timer_mem_register(struct device_node *np, void *frame)
else
irq = irq_of_parse_and_map(frame_node, PHYS_SPI);
} else {
- pr_err("Device node is missing.\n");
- return -EINVAL;
+ frame_data = (struct gt_timer_data *)frame;
+ /*
+ * According to ARMv8 Architecture Reference Manual(ARM),
+ * the size of CNTBaseN frames of memory-mapped timer
+ * is SZ_4K(Offset 0x000 – 0xFFF).
+ */
+ base = ioremap(frame_data->cntbase_phy, SZ_4K);
+ if (arch_timer_mem_use_virtual)
+ irq = frame_data->virtual_irq;
+ else
+ irq = frame_data->irq;
}

if (!base) {
@@ -840,13 +850,16 @@ static int __init arch_timer_of_init(struct device_node *np)
CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_of_init);
CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_of_init);

-static int __init get_cnttidr(struct device_node *np, u32 *cnttidr)
+static int __init get_cnttidr(struct device_node *np,
+ struct gt_block_data *gt_block, u32 *cnttidr)
{
if (!cnttidr)
return -EINVAL;

if (np)
cntctlbase = of_iomap(np, 0);
+ else if (gt_block)
+ cntctlbase = ioremap(gt_block->cntctlbase_phy, SZ_4K);
else
return -EINVAL;

@@ -885,7 +898,7 @@ static int __init arch_timer_mem_init(struct device_node *np)

arch_timers_present |= ARCH_MEM_TIMER;

- ret = get_cnttidr(np, &cnttidr);
+ ret = get_cnttidr(np, NULL, &cnttidr);
if (ret)
return ret;

@@ -921,7 +934,72 @@ CLOCKSOURCE_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem",
arch_timer_mem_init);

#ifdef CONFIG_ACPI_GTDT
-/* Initialize per-processor generic timer */
+static struct gt_timer_data __init *arch_timer_mem_get_timer(
+ struct gt_block_data *gt_blocks)
+{
+ struct gt_block_data *gt_block = gt_blocks;
+ struct gt_timer_data *best_frame = NULL;
+ u32 cnttidr;
+ int i;
+
+ if (get_cnttidr(NULL, gt_block, &cnttidr))
+ return NULL;
+ /*
+ * Try to find a virtual capable frame. Otherwise fall back to a
+ * physical capable frame.
+ */
+ for (i = 0; i < gt_block->timer_count; i++) {
+ if (is_best_frame(cnttidr, gt_block->timer[i].frame_nr)) {
+ best_frame = &gt_block->timer[i];
+ if (arch_timer_mem_use_virtual)
+ break;
+ }
+ }
+ iounmap(cntctlbase);
+
+ return best_frame;
+}
+
+static int __init arch_timer_mem_acpi_init(size_t timer_count)
+{
+ struct gt_block_data *gt_blocks;
+ struct gt_timer_data *gt_timer;
+ int ret = -EINVAL;
+
+ /*
+ * If we don't have any Platform Timer Structures, just return.
+ */
+ if (!timer_count)
+ return 0;
+
+ /*
+ * before really check all the Platform Timer Structures,
+ * we assume they are GT block, and allocate memory for them.
+ * We will free these memory once we finish the initialization.
+ */
+ gt_blocks = kcalloc(timer_count, sizeof(*gt_blocks), GFP_KERNEL);
+ if (!gt_blocks)
+ return -ENOMEM;
+
+ if (gtdt_arch_timer_mem_init(gt_blocks) > 0) {
+ gt_timer = arch_timer_mem_get_timer(gt_blocks);
+ if (!gt_timer) {
+ pr_err("Failed to get mem timer info.\n");
+ goto error;
+ }
+ ret = arch_timer_mem_register(NULL, gt_timer);
+ if (ret) {
+ pr_err("Failed to register mem timer.\n");
+ goto error;
+ }
+ }
+ arch_timers_present |= ARCH_MEM_TIMER;
+error:
+ kfree(gt_blocks);
+ return ret;
+}
+
+/* Initialize per-processor generic timer and memory-mapped timer(if present) */
static int __init arch_timer_acpi_init(struct acpi_table_header *table)
{
int timer_count;
@@ -945,8 +1023,8 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *table)
/* Get the frequency from CNTFRQ */
arch_timer_detect_rate(NULL, NULL);

- if (timer_count < 0)
- pr_err("Failed to get platform timer info.\n");
+ if (timer_count < 0 || arch_timer_mem_acpi_init((size_t)timer_count))
+ pr_err("Failed to initialize memory-mapped timer.\n");

return arch_timer_init();
}
--
2.7.4
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