[PATCH v2 1/2] arm64: zynqmp: Print an error for split to lock mode switch

[Padmarao Begari]

The zynqmp tcminit crashes the U-Boot when switching from
r5-mode "split" to "lockstep" instead it should throw an error.
When cpu is enabled, the check_tcm_mode() function checks
if the previous mode is "split", switch mode is "lockstep" then
it returns the error code and the initialize_tcm() function is not
updating the global control register of the RPU instead it prints
the error message. When cpu is disabled, the check_tcm_mode()
function returns the success code for switch split to lockstep mode.

Signed-off-by: Padmarao Begari <padmarao.begari at amd.com>
---
 arch/arm/mach-zynqmp/cpu.c                    | 16 ++++++++++---
 arch/arm/mach-zynqmp/include/mach/sys_proto.h |  1 +
 arch/arm/mach-zynqmp/mp.c                     | 24 +++++++++++++++++++
 3 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/arch/arm/mach-zynqmp/cpu.c b/arch/arm/mach-zynqmp/cpu.c
index 07668c9468..b24c163147 100644
--- a/arch/arm/mach-zynqmp/cpu.c
+++ b/arch/arm/mach-zynqmp/cpu.c
@@ -115,9 +115,19 @@ u64 get_page_table_size(void)
 #if defined(CONFIG_SYS_MEM_RSVD_FOR_MMU) || defined(CONFIG_DEFINE_TCM_OCM_MMAP)
 void tcm_init(u8 mode)
 {
-	puts("WARNING: Initializing TCM overwrites TCM content\n");
-	initialize_tcm(mode);
-	memset((void *)ZYNQMP_TCM_BASE_ADDR, 0, ZYNQMP_TCM_SIZE);
+	int ret;
+
+	ret = check_tcm_mode(mode);
+	if (!ret) {
+		puts("WARNING: Initializing TCM overwrites TCM content\n");
+		initialize_tcm(mode);
+		memset((void *)ZYNQMP_TCM_BASE_ADDR, 0, ZYNQMP_TCM_SIZE);
+	}
+
+	if (ret == -EACCES)
+		printf("ERROR: Split to lockstep mode required reset/disable cpu\n");
+
+	/* Ignore if ret is -EAGAIN, trying to initialize same mode again */
 }
 #endif
 
diff --git a/arch/arm/mach-zynqmp/include/mach/sys_proto.h b/arch/arm/mach-zynqmp/include/mach/sys_proto.h
index 15b69e7771..b3396db28f 100644
--- a/arch/arm/mach-zynqmp/include/mach/sys_proto.h
+++ b/arch/arm/mach-zynqmp/include/mach/sys_proto.h
@@ -48,6 +48,7 @@ enum {
 
 unsigned int zynqmp_get_silicon_version(void);
 
+int check_tcm_mode(bool mode);
 void initialize_tcm(bool mode);
 void mem_map_fill(void);
 #if defined(CONFIG_SYS_MEM_RSVD_FOR_MMU) || defined(CONFIG_DEFINE_TCM_OCM_MMAP)
diff --git a/arch/arm/mach-zynqmp/mp.c b/arch/arm/mach-zynqmp/mp.c
index 9b46a25a1c..6e6da8008f 100644
--- a/arch/arm/mach-zynqmp/mp.c
+++ b/arch/arm/mach-zynqmp/mp.c
@@ -12,7 +12,9 @@
 #include <asm/arch/hardware.h>
 #include <asm/arch/sys_proto.h>
 #include <asm/io.h>
+#include <linux/bitfield.h>
 #include <linux/delay.h>
+#include <linux/errno.h>
 #include <linux/string.h>
 
 #define LOCK		0
@@ -264,6 +266,28 @@ void initialize_tcm(bool mode)
 	}
 }
 
+int check_tcm_mode(bool mode)
+{
+	u32 tmp, cpu_state;
+	bool mode_prev;
+
+	tmp = readl(&rpu_base->rpu_glbl_ctrl);
+	mode_prev = FIELD_GET(ZYNQMP_RPU_GLBL_CTRL_SPLIT_LOCK_MASK, tmp);
+
+	tmp = readl(&crlapb_base->rst_lpd_top);
+	cpu_state = FIELD_GET(ZYNQMP_CRLAPB_RST_LPD_R50_RST_MASK |
+			      ZYNQMP_CRLAPB_RST_LPD_R51_RST_MASK, tmp);
+	cpu_state = cpu_state ? false : true;
+
+	if ((mode_prev == SPLIT && mode == LOCK) && cpu_state)
+		return -EACCES;
+
+	if (mode_prev == mode)
+		return -EAGAIN;
+
+	return 0;
+}
+
 static void mark_r5_used(u32 nr, u8 mode)
 {
 	u32 mask = 0;
-- 
2.25.1