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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>
This commit is contained in:
Patrick Delaunay 2020-06-16 18:27:44 +02:00
parent 03c4e6224a
commit bd3f60d29c
3 changed files with 50 additions and 4 deletions
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25
arch/arm/mach-stm32mp/bsec.c
View File

@ -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 @@ U_BOOT_DRIVER(stm32mp_bsec) = {
.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;
}

22
arch/arm/mach-stm32mp/cpu.c
View File

@ -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 @@ static void dbgmcu_init(void)
{
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 @@ void enable_caches(void)
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)

7
arch/arm/mach-stm32mp/include/mach/bsec.h Normal file
View File

@ -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);