[U-Boot] [PATCH v3 2/6] dm: x86: Allow TSC timer to be used before DM is ready

[Simon Glass]

With bootstage we need access to the timer before driver model is set up.
To handle this, put the required state in global_data and provide a new
function to set up the device, separate from the driver's probe() method.

This will be used by the 'early' timer also.

Signed-off-by: Simon Glass <sjg at chromium.org>
Reviewed-by: Bin Meng <bmeng.cn at gmail.com>
---

Changes in v3: None
Changes in v2:
- Update to support the early timer

 arch/x86/include/asm/global_data.h |  1 +
 drivers/timer/tsc_timer.c          | 30 +++++++++++++++++++++++++-----
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/global_data.h b/arch/x86/include/asm/global_data.h
index 93a80fe2b6..fcb6853a38 100644
--- a/arch/x86/include/asm/global_data.h
+++ b/arch/x86/include/asm/global_data.h
@@ -77,6 +77,7 @@ struct arch_global_data {
 	uint8_t x86_mask;
 	uint32_t x86_device;
 	uint64_t tsc_base;		/* Initial value returned by rdtsc() */
+	unsigned long clock_rate;	/* Clock rate of timer in Hz */
 	void *new_fdt;			/* Relocated FDT */
 	uint32_t bist;			/* Built-in self test value */
 	enum pei_boot_mode_t pei_boot_mode;
diff --git a/drivers/timer/tsc_timer.c b/drivers/timer/tsc_timer.c
index 4d1fc9cd13..0012fecde0 100644
--- a/drivers/timer/tsc_timer.c
+++ b/drivers/timer/tsc_timer.c
@@ -328,17 +328,17 @@ static int tsc_timer_get_count(struct udevice *dev, u64 *count)
 	return 0;
 }
 
-static int tsc_timer_probe(struct udevice *dev)
+static void tsc_timer_ensure_setup(void)
 {
-	struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
-
+	if (gd->arch.tsc_base)
+		return;
 	gd->arch.tsc_base = rdtsc();
 
 	/*
 	 * If there is no clock frequency specified in the device tree,
 	 * calibrate it by ourselves.
 	 */
-	if (!uc_priv->clock_rate) {
+	if (!gd->arch.clock_rate) {
 		unsigned long fast_calibrate;
 
 		fast_calibrate = cpu_mhz_from_msr();
@@ -348,12 +348,32 @@ static int tsc_timer_probe(struct udevice *dev)
 				panic("TSC frequency is ZERO");
 		}
 
-		uc_priv->clock_rate = fast_calibrate * 1000000;
+		gd->arch.clock_rate = fast_calibrate * 1000000;
 	}
+}
+
+static int tsc_timer_probe(struct udevice *dev)
+{
+	struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+
+	tsc_timer_ensure_setup();
+	uc_priv->clock_rate = gd->arch.clock_rate;
 
 	return 0;
 }
 
+unsigned long notrace timer_early_get_rate(void)
+{
+	tsc_timer_ensure_setup();
+
+	return gd->arch.clock_rate;
+}
+
+u64 notrace timer_early_get_count(void)
+{
+	return rdtsc() - gd->arch.tsc_base;
+}
+
 static const struct timer_ops tsc_timer_ops = {
 	.get_count = tsc_timer_get_count,
 };
-- 
2.14.1.581.gf28d330327-goog