In case of an OTP-CLOSED STM32MP15xx system, the CPU core 1 cannot be released from endless loop in BootROM only by populating TAMP BKPxR 4 and 5 with magic and branch address and sending SGI0 interrupt from core 0 to core 1 twice. TAMP_SMCR BKP..PROT fields must be initialized as well to release the core 1 from endless loop during the second SGI0 handling on core 1. Initialize TAMP_SMCR to protect the first 32 backup registers, the ones which contain the core 1 magic, branch address and boot information.
This requirement seems to be undocumented, therefore it was necessary to trace and analyze the STM32MP15xx BootROM using OpenOCD and objdump. Ultimately, it turns out that a certain BootROM function reads out the TAMP_SMCR register and tests whether the BKP..PROT fields are non-zero. If they are zero, the BootROM code again waits for SGI0 using WFI, else the execution moves forward until it reaches handoff to the TAMP BKPxR 5 branch address.
This fixes CPU core 1 release using U-Boot PSCI implementation on an OTP-CLOSED system, i.e. system with fuse 0 bit 6 set.
Reviewed-by: Patrick Delaunay patrick.delaunay@foss.st.com Signed-off-by: Marek Vasut marex@denx.de --- Cc: Igor Opaniuk igor.opaniuk@foundries.io Cc: Patrice Chotard patrice.chotard@foss.st.com Cc: Patrick Delaunay patrick.delaunay@foss.st.com Cc: Simon Glass <sjg@chromium.org Cc: Simon Glass sjg@chromium.org Cc: Tom Rini trini@konsulko.com Cc: u-boot@dh-electronics.com Cc: uboot-stm32@st-md-mailman.stormreply.com --- V2: Fix up the BKPRWD/BKPWD mask typo V3: - Update the allocation to 0x20/0x20 - Update commit message - Add RB from Patrick --- arch/arm/mach-stm32mp/stm32mp1/stm32mp15x.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/arch/arm/mach-stm32mp/stm32mp1/stm32mp15x.c b/arch/arm/mach-stm32mp/stm32mp1/stm32mp15x.c index dd99150fbc2..d75ec99d6a1 100644 --- a/arch/arm/mach-stm32mp/stm32mp1/stm32mp15x.c +++ b/arch/arm/mach-stm32mp/stm32mp1/stm32mp15x.c @@ -14,6 +14,7 @@ #include <asm/arch/sys_proto.h> #include <dm/device.h> #include <dm/uclass.h> +#include <linux/bitfield.h>
/* RCC register */ #define RCC_TZCR (STM32_RCC_BASE + 0x00) @@ -41,6 +42,9 @@ #define TZC_REGION_ID_ACCESS0 (STM32_TZC_BASE + 0x114)
#define TAMP_CR1 (STM32_TAMP_BASE + 0x00) +#define TAMP_SMCR (STM32_TAMP_BASE + 0x20) +#define TAMP_SMCR_BKPRWDPROT GENMASK(7, 0) +#define TAMP_SMCR_BKPWDPROT GENMASK(23, 16)
#define PWR_CR1 (STM32_PWR_BASE + 0x00) #define PWR_MCUCR (STM32_PWR_BASE + 0x14) @@ -136,6 +140,18 @@ static void security_init(void) */ writel(0x0, TAMP_CR1);
+ /* + * TAMP: Configure non-zero secure protection settings. This is + * checked by BootROM function 35ac on OTP-CLOSED device during + * CPU core 1 release from endless loop. If secure protection + * fields are zero, the core 1 is not released from endless + * loop on second SGI0. + */ + clrsetbits_le32(TAMP_SMCR, + TAMP_SMCR_BKPRWDPROT | TAMP_SMCR_BKPWDPROT, + FIELD_PREP(TAMP_SMCR_BKPRWDPROT, 0x20) | + FIELD_PREP(TAMP_SMCR_BKPWDPROT, 0x20)); + /* GPIOZ: deactivate the security */ writel(BIT(0), RCC_MP_AHB5ENSETR); writel(0x0, GPIOZ_SECCFGR);