stm32mp: bsec: add permanent lock write support

Add support of the permanent lock support in U-Boot proper
when BSEC is not managed by secure monitor (TF-A SP_MIN or OP-TEE).

This patch avoid issue with stm32key command and fuse command
on basic boot for this missing feature of U-Boot BSEC driver.

Reported-by: Johann Neuhauser <jneuhauser@dh-electronics.com>
Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Tested-by: Johann Neuhauser <jneuhauser@dh-electronics.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>

diff --git a/arch/arm/mach-stm32mp/bsec.c b/arch/arm/mach-stm32mp/bsec.c
index 27d1829..fd6e1a3 100644 (file)
--- a/arch/arm/mach-stm32mp/bsec.c
+++ b/arch/arm/mach-stm32mp/bsec.c
@@ -18,6 +18,7 @@
 #include <linux/iopoll.h>
 
 #define BSEC_OTP_MAX_VALUE             95
+#define BSEC_OTP_UPPER_START           32
 #define BSEC_TIMEOUT_US                        10000
 
 /* BSEC REGISTER OFFSET (base relative) */
@@ -41,6 +42,7 @@
 /* BSEC_CONTROL Register */
 #define BSEC_READ                      0x000
 #define BSEC_WRITE                     0x100
+#define BSEC_LOCK                      0x200
 
 /* LOCK Register */
 #define OTP_LOCK_MASK                  0x1F
@@ -61,6 +63,11 @@
  */
 #define BSEC_LOCK_PROGRAM              0x04
 
+/*
+ * OTP status: bit 0 permanent lock
+ */
+#define BSEC_LOCK_PERM                 BIT(0)
+
 /**
  * bsec_lock() - manage lock for each type SR/SP/SW
  * @address: address of bsec IP register
@@ -284,6 +291,65 @@ static int bsec_program_otp(struct udevice *dev, long base, u32 val, u32 otp)
        return ret;
 }
 
+/**
+ * bsec_permanent_lock_otp() - permanent lock of OTP in SAFMEM
+ * @dev: bsec IP device
+ * @base: base address of bsec IP
+ * @otp: otp number (0 - BSEC_OTP_MAX_VALUE)
+ * Return: 0 if no error
+ */
+static int bsec_permanent_lock_otp(struct udevice *dev, long base, uint32_t otp)
+{
+       int ret;
+       bool power_up = false;
+       u32 val, addr;
+
+       /* check if safemem is power up */
+       if (!(readl(base + BSEC_OTP_STATUS_OFF) & BSEC_MODE_PWR_MASK)) {
+               ret = bsec_power_safmem(base, true);
+               if (ret)
+                       return ret;
+
+               power_up = true;
+       }
+
+       /*
+        * low OTPs = 2 bits word for low OTPs, 1 bits per word for upper OTP
+        * and only 16 bits used in WRDATA
+        */
+       if (otp < BSEC_OTP_UPPER_START) {
+               addr = otp / 8;
+               val = 0x03 << ((otp * 2) & 0xF);
+       } else {
+               addr = BSEC_OTP_UPPER_START / 8 +
+                      ((otp - BSEC_OTP_UPPER_START) / 16);
+               val = 0x01 << (otp & 0xF);
+       }
+
+       /* set value in write register*/
+       writel(val, base + BSEC_OTP_WRDATA_OFF);
+
+       /* set BSEC_OTP_CTRL_OFF with the otp addr and lock request*/
+       writel(addr | BSEC_WRITE | BSEC_LOCK, base + BSEC_OTP_CTRL_OFF);
+
+       /* check otp status*/
+       ret = readl_poll_timeout(base + BSEC_OTP_STATUS_OFF,
+                                val, (val & BSEC_MODE_BUSY_MASK) == 0,
+                                BSEC_TIMEOUT_US);
+       if (ret)
+               return ret;
+
+       if (val & BSEC_MODE_PROGFAIL_MASK)
+               ret = -EACCES;
+       else
+               ret = bsec_check_error(base, otp);
+
+       if (power_up)
+               bsec_power_safmem(base, false);
+
+       return ret;
+}
+
 /* BSEC MISC driver *******************************************************/
 struct stm32mp_bsec_plat {
        u32 base;
@@ -339,9 +405,14 @@ static int stm32mp_bsec_read_shadow(struct udevice *dev, u32 *val, u32 otp)
 static int stm32mp_bsec_read_lock(struct udevice *dev, u32 *val, u32 otp)
 {
        struct stm32mp_bsec_plat *plat = dev_get_plat(dev);
+       u32 wrlock;
 
        /* return OTP permanent write lock status */
-       *val = bsec_read_lock(plat->base + BSEC_WRLOCK_OFF, otp);
+       wrlock = bsec_read_lock(plat->base + BSEC_WRLOCK_OFF, otp);
+
+       *val = 0;
+       if (wrlock)
+               *val = BSEC_LOCK_PERM;
 
        return 0;
 }
@@ -377,15 +448,22 @@ static int stm32mp_bsec_write_shadow(struct udevice *dev, u32 val, u32 otp)
 
 static int stm32mp_bsec_write_lock(struct udevice *dev, u32 val, u32 otp)
 {
-       if (!IS_ENABLED(CONFIG_ARM_SMCCC) || IS_ENABLED(CONFIG_SPL_BUILD))
-               return -ENOTSUPP;
+       struct stm32mp_bsec_plat *plat;
+
+       /* only permanent write lock is supported in U-Boot */
+       if (!(val & BSEC_LOCK_PERM)) {
+               dev_dbg(dev, "lock option without BSEC_LOCK_PERM: %x\n", val);
+               return 0; /* nothing to do */
+       }
 
-       if (val == 1)
+       if (IS_ENABLED(CONFIG_ARM_SMCCC) && !IS_ENABLED(CONFIG_SPL_BUILD))
                return stm32_smc_exec(STM32_SMC_BSEC,
                                      STM32_SMC_WRLOCK_OTP,
                                      otp, 0);
-       if (val == 0)
-               return 0; /* nothing to do */
+
+       plat = dev_get_plat(dev);
+
+       return bsec_permanent_lock_otp(dev, plat->base, otp);
 
        return -EINVAL;
 }