arm: stm32mp: protect DBGMCU_IDC access with BSEC
As debugger must be totally closed on Sec closed chip,
the DBGMCU_IDC register is no more accessible (self
hosted debug is disabled with OTP).
This patch adds a function bsec_dbgswenable() to check
if the DBGMCU registers are available before to access them:
BSEC_DENABLE.DBGSWENABLE = self hosted debug status.
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
diff --git a/arch/arm/mach-stm32mp/bsec.c b/arch/arm/mach-stm32mp/bsec.c
index 059ef0b..0c56b44 100644
--- a/arch/arm/mach-stm32mp/bsec.c
+++ b/arch/arm/mach-stm32mp/bsec.c
@@ -8,6 +8,7 @@
#include <log.h>
#include <misc.h>
#include <asm/io.h>
+#include <asm/arch/bsec.h>
#include <asm/arch/stm32mp1_smc.h>
#include <linux/arm-smccc.h>
#include <linux/iopoll.h>
@@ -21,6 +22,7 @@
#define BSEC_OTP_WRDATA_OFF 0x008
#define BSEC_OTP_STATUS_OFF 0x00C
#define BSEC_OTP_LOCK_OFF 0x010
+#define BSEC_DENABLE_OFF 0x014
#define BSEC_DISTURBED_OFF 0x01C
#define BSEC_ERROR_OFF 0x034
#define BSEC_WRLOCK_OFF 0x04C /* OTP write permananet lock */
@@ -46,6 +48,9 @@
#define BSEC_MODE_PROGFAIL_MASK 0x10
#define BSEC_MODE_PWR_MASK 0x20
+/* DENABLE Register */
+#define BSEC_DENABLE_DBGSWENABLE BIT(10)
+
/*
* OTP Lock services definition
* Value must corresponding to the bit number in the register
@@ -506,3 +511,23 @@
.ops = &stm32mp_bsec_ops,
.probe = stm32mp_bsec_probe,
};
+
+bool bsec_dbgswenable(void)
+{
+ struct udevice *dev;
+ struct stm32mp_bsec_platdata *plat;
+ int ret;
+
+ ret = uclass_get_device_by_driver(UCLASS_MISC,
+ DM_GET_DRIVER(stm32mp_bsec), &dev);
+ if (ret || !dev) {
+ pr_debug("bsec driver not available\n");
+ return false;
+ }
+
+ plat = dev_get_platdata(dev);
+ if (readl(plat->base + BSEC_DENABLE_OFF) & BSEC_DENABLE_DBGSWENABLE)
+ return true;
+
+ return false;
+}
diff --git a/arch/arm/mach-stm32mp/cpu.c b/arch/arm/mach-stm32mp/cpu.c
index 472b140..3820671 100644
--- a/arch/arm/mach-stm32mp/cpu.c
+++ b/arch/arm/mach-stm32mp/cpu.c
@@ -12,6 +12,7 @@
#include <misc.h>
#include <net.h>
#include <asm/io.h>
+#include <asm/arch/bsec.h>
#include <asm/arch/stm32.h>
#include <asm/arch/sys_proto.h>
#include <dm/device.h>
@@ -155,8 +156,13 @@
{
setbits_le32(RCC_DBGCFGR, RCC_DBGCFGR_DBGCKEN);
- /* Freeze IWDG2 if Cortex-A7 is in debug mode */
- setbits_le32(DBGMCU_APB4FZ1, DBGMCU_APB4FZ1_IWDG2);
+ /*
+ * Freeze IWDG2 if Cortex-A7 is in debug mode
+ * done in TF-A for TRUSTED boot and
+ * DBGMCU access is controlled by BSEC_DENABLE.DBGSWENABLE
+ */
+ if (!IS_ENABLED(CONFIG_TFABOOT) && bsec_dbgswenable())
+ setbits_le32(DBGMCU_APB4FZ1, DBGMCU_APB4FZ1_IWDG2);
}
#endif /* !defined(CONFIG_SPL) || defined(CONFIG_SPL_BUILD) */
@@ -276,9 +282,17 @@
static u32 read_idc(void)
{
- setbits_le32(RCC_DBGCFGR, RCC_DBGCFGR_DBGCKEN);
+ /* DBGMCU access is controlled by BSEC_DENABLE.DBGSWENABLE */
+ if (bsec_dbgswenable()) {
+ setbits_le32(RCC_DBGCFGR, RCC_DBGCFGR_DBGCKEN);
- return readl(DBGMCU_IDC);
+ return readl(DBGMCU_IDC);
+ }
+
+ if (CONFIG_IS_ENABLED(STM32MP15x))
+ return CPU_DEV_STM32MP15; /* STM32MP15x and unknown revision */
+ else
+ return 0x0;
}
u32 get_cpu_dev(void)
diff --git a/arch/arm/mach-stm32mp/include/mach/bsec.h b/arch/arm/mach-stm32mp/include/mach/bsec.h
new file mode 100644
index 0000000..252eac3
--- /dev/null
+++ b/arch/arm/mach-stm32mp/include/mach/bsec.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause */
+/*
+ * Copyright (C) 2020, STMicroelectronics - All Rights Reserved
+ */
+
+/* check self hosted debug status = BSEC_DENABLE.DBGSWENABLE */
+bool bsec_dbgswenable(void);