[PATCH] arm: mach-k3: am625_init: Add Erratum WA for RTC startup
From: Nishanth Menon nm@ti.com
Add erratum i2327 work around for initialization for RTC interrupt where interrupt is stuck for ever at startup. Unfortunately, this workaround needs to be applied under 1 second of boot.
Signed-off-by: Nishanth Menon nm@ti.com [bb@ti.com: rebased from 2021.01] Signed-off-by: Bryan Brattlof bb@ti.com --- arch/arm/mach-k3/am625_init.c | 44 +++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+)
diff --git a/arch/arm/mach-k3/am625_init.c b/arch/arm/mach-k3/am625_init.c index a91c15ca4e188..e90c18fdcc118 100644 --- a/arch/arm/mach-k3/am625_init.c +++ b/arch/arm/mach-k3/am625_init.c @@ -15,6 +15,15 @@ #include <dm/uclass-internal.h> #include <dm/pinctrl.h>
+#define RTC_BASE_ADDRESS 0x2b1f0000 +#define REG_K3RTC_S_CNT_LSW (RTC_BASE_ADDRESS + 0x18) +#define REG_K3RTC_KICK0 (RTC_BASE_ADDRESS + 0x70) +#define REG_K3RTC_KICK1 (RTC_BASE_ADDRESS + 0x74) + +/* Magic values for lock/unlock */ +#define K3RTC_KICK0_UNLOCK_VALUE 0x83e70b13 +#define K3RTC_KICK1_UNLOCK_VALUE 0x95a4f1e0 + /* * This uninitialized global variable would normal end up in the .bss section, * but the .bss is cleared between writing and reading this variable, so move @@ -71,6 +80,40 @@ static __maybe_unused void enable_mcu_esm_reset(void) writel(stat, CTRLMMR_MCU_RST_CTRL); }
+#if defined(CONFIG_CPU_V7R) + +/* + * RTC Erratum i2327 Workaround + * Due to a bug in initial synchronization out of cold power on, + * IRQ status can get locked infinitely if we do not: + * a) unlock RTC + * + * This workaround *must* be applied within 1 second of power on, + * So, this is closest point to be able to guarantee the max + * timing. + */ +void rtc_erratumi2327_init(void) +{ + u32 counter; + + /* + * If counter has gone past 1, nothing we can do, leave + * system locked! This is the only way we know if RTC + * can be used for all practical purposes. + */ + counter = readl(REG_K3RTC_S_CNT_LSW); + if (counter > 1) + return; + /* + * Need to set this up at the very start + * MUST BE DONE under 1 second of boot. + */ + writel(K3RTC_KICK0_UNLOCK_VALUE, REG_K3RTC_KICK0); + writel(K3RTC_KICK1_UNLOCK_VALUE, REG_K3RTC_KICK1); + return; +} +#endif + void board_init_f(ulong dummy) { struct udevice *dev; @@ -78,6 +121,7 @@ void board_init_f(ulong dummy)
#if defined(CONFIG_CPU_V7R) setup_k3_mpu_regions(); + rtc_erratumi2327_init(); #endif
/*
base-commit: a25dcda452bf6a6de72764a8d990d72e5def643d
On 14:26-20230427, Bryan Brattlof wrote:
From: Nishanth Menon nm@ti.com
Add erratum i2327 work around for initialization for RTC interrupt where interrupt is stuck for ever at startup. Unfortunately, this workaround needs to be applied under 1 second of boot.
Signed-off-by: Nishanth Menon nm@ti.com [bb@ti.com: rebased from 2021.01] Signed-off-by: Bryan Brattlof bb@ti.com
It will be good to state in the diffstat that am62a7 or other k3 SoCs are not impacted: am62a7 has the hardware fix and other SoCs do not have this rtc.
I dont think there is a need to respin the patch for that - just clarifying.
arch/arm/mach-k3/am625_init.c | 44 +++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+)
diff --git a/arch/arm/mach-k3/am625_init.c b/arch/arm/mach-k3/am625_init.c index a91c15ca4e188..e90c18fdcc118 100644 --- a/arch/arm/mach-k3/am625_init.c +++ b/arch/arm/mach-k3/am625_init.c @@ -15,6 +15,15 @@ #include <dm/uclass-internal.h> #include <dm/pinctrl.h>
+#define RTC_BASE_ADDRESS 0x2b1f0000 +#define REG_K3RTC_S_CNT_LSW (RTC_BASE_ADDRESS + 0x18) +#define REG_K3RTC_KICK0 (RTC_BASE_ADDRESS + 0x70) +#define REG_K3RTC_KICK1 (RTC_BASE_ADDRESS + 0x74)
+/* Magic values for lock/unlock */ +#define K3RTC_KICK0_UNLOCK_VALUE 0x83e70b13 +#define K3RTC_KICK1_UNLOCK_VALUE 0x95a4f1e0
/*
- This uninitialized global variable would normal end up in the .bss section,
- but the .bss is cleared between writing and reading this variable, so move
@@ -71,6 +80,40 @@ static __maybe_unused void enable_mcu_esm_reset(void) writel(stat, CTRLMMR_MCU_RST_CTRL); }
+#if defined(CONFIG_CPU_V7R)
+/*
- RTC Erratum i2327 Workaround
- Due to a bug in initial synchronization out of cold power on,
- IRQ status can get locked infinitely if we do not:
- a) unlock RTC
- This workaround *must* be applied within 1 second of power on,
- So, this is closest point to be able to guarantee the max
- timing.
- */
+void rtc_erratumi2327_init(void) +{
- u32 counter;
- /*
* If counter has gone past 1, nothing we can do, leave* system locked! This is the only way we know if RTC* can be used for all practical purposes.*/- counter = readl(REG_K3RTC_S_CNT_LSW);
- if (counter > 1)
return;- /*
* Need to set this up at the very start* MUST BE DONE under 1 second of boot.*/- writel(K3RTC_KICK0_UNLOCK_VALUE, REG_K3RTC_KICK0);
- writel(K3RTC_KICK1_UNLOCK_VALUE, REG_K3RTC_KICK1);
- return;
+} +#endif
void board_init_f(ulong dummy) { struct udevice *dev; @@ -78,6 +121,7 @@ void board_init_f(ulong dummy)
#if defined(CONFIG_CPU_V7R) setup_k3_mpu_regions();
- rtc_erratumi2327_init();
#endif
/*
base-commit: a25dcda452bf6a6de72764a8d990d72e5def643d
2.40.0
participants (2)
-
Bryan Brattlof -
Nishanth Menon