From 4d4214a8dea31d531df6739e6f74005090018faa Mon Sep 17 00:00:00 2001
From: Yann Gautier <yann.gautier@st.com>
Date: Wed, 24 Apr 2019 13:38:41 +0200
Subject: [PATCH 5/7] stm32mp: add function to protect access on PWR registers

In SMP context, we need to add spinlocks to protect against concurrent
accesses on PWR registers.

Change-Id: I27cb698ffa085eca7b61b042ce5ccaa1fd2daaf4
Signed-off-by: Yann Gautier <yann.gautier@st.com>
---
 plat/st/common/include/stm32mp_common.h |  4 ++++
 plat/st/common/stm32mp_common.c         | 17 +++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/plat/st/common/include/stm32mp_common.h b/plat/st/common/include/stm32mp_common.h
index 4f8567979..052402854 100644
--- a/plat/st/common/include/stm32mp_common.h
+++ b/plat/st/common/include/stm32mp_common.h
@@ -33,6 +33,10 @@ uintptr_t stm32mp_rcc_base(void);
 /* Check MMU status to allow spinlock use */
 bool stm32mp_lock_available(void);
 
+/* SMP protection on PWR registers access */
+void stm32mp_pwr_regs_lock(void);
+void stm32mp_pwr_regs_unlock(void);
+
 /* Get IWDG platform instance ID from peripheral IO memory base address */
 uint32_t stm32_iwdg_get_instance(uintptr_t base);
 
diff --git a/plat/st/common/stm32mp_common.c b/plat/st/common/stm32mp_common.c
index afa87f487..5e7c74b48 100644
--- a/plat/st/common/stm32mp_common.c
+++ b/plat/st/common/stm32mp_common.c
@@ -12,8 +12,11 @@
 #include <arch_helpers.h>
 #include <common/debug.h>
 #include <drivers/st/stm32mp_clkfunc.h>
+#include <lib/spinlock.h>
 #include <plat/common/platform.h>
 
+static struct spinlock lock;
+
 uintptr_t plat_get_ns_image_entrypoint(void)
 {
 	return BL33_BASE;
@@ -96,6 +99,20 @@ bool stm32mp_lock_available(void)
 	return (read_sctlr() & c_m_bits) == c_m_bits;
 }
 
+void stm32mp_pwr_regs_lock(void)
+{
+	if (stm32mp_lock_available()) {
+		spin_lock(&lock);
+	}
+}
+
+void stm32mp_pwr_regs_unlock(void)
+{
+	if (stm32mp_lock_available()) {
+		spin_unlock(&lock);
+	}
+}
+
 uintptr_t stm32_get_gpio_bank_base(unsigned int bank)
 {
 	if (bank == GPIO_BANK_Z) {
-- 
2.27.0