imx: Enable ACTLR.SMP bit for all i.MX cortex-a7 platforms

PATCH New Fabio Estevam 2 participants 2 messages May 14, 2018 – Jun 18, 2018

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Arm (32-bit) Arm sub-architectures Arm i.MX and Layerscape

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Fabio Estevam

author reviewer

2018-05-14 12:44 UTC #0 lore raw

PATCH 1/1 imx: Enable ACTLR.SMP bit for all i.MX cortex-a7 platforms

From: Ye Li <[email protected]>

According to the Cortex-A7 TRM, for ACTLR.SMP bit "You must ensure this bit is set to 1 before the caches and MMU are enabled, or any cache and TLB maintenance operations are performed".
ROM sets this bit in normal boot flow, but when in serial download mode, it is not set.
Here we add it in u-boot as a common flow for all i.MX cortex-a7 platforms, including mx7d, mx6ul/ull and mx7ulp.

Signed-off-by Ye Li <[email protected]>

[fabio: adapted to U-Boot mainline codebase and make checkpatch happy]

Signed-off-by Fabio Estevam <[email protected]>

---
 arch/arm/mach-imx/cache.c   | 42 ++++++++++++++++++++++++++++++++++++++++++
 arch/arm/mach-imx/mx7/soc.c |  7 -------
 2 files changed, 42 insertions(+), 7 deletions(-)

arch/arm/mach-imx/cache.c +42 -0

index c5279a7..86205cf 100644
@@ -10,6 +10,34 @@
 #include <asm/io.h>
 #include <asm/mach-imx/sys_proto.h>
 
+static void enable_ca7_smp(void)
+{
+	u32 val;
+
+	/* Read MIDR */
+	asm volatile ("mrc p15, 0, %0, c0, c0, 0\n\t" : "=r"(val));
+	val = (val >> 4);
+	val &= 0xf;
+
+	/* Only set the SMP for Cortex A7 */
+	if (val == 0x7) {
+		/* Read auxiliary control register */
+		asm volatile ("mrc p15, 0, %0, c1, c0, 1\n\t" : "=r"(val));
+
+		if (val & (1 << 6))
+			return;
+
+		/* Enable SMP */
+		val |= (1 << 6);
+
+		/* Write auxiliary control register */
+		asm volatile ("mcr p15, 0, %0, c1, c0, 1\n\t" : : "r"(val));
+
+		DSB;
+		ISB;
+	}
+}
+
 #ifndef CONFIG_SYS_DCACHE_OFF
 void enable_caches(void)
 {

@@ -21,6 +49,9 @@ void enable_caches(void)
 	/* Avoid random hang when download by usb */
 	invalidate_dcache_all();
 
+	/* Set ACTLR.SMP bit for Cortex-A7 */
+	enable_ca7_smp();
+
 	/* Enable D-cache. I-cache is already enabled in start.S */
 	dcache_enable();

@@ -32,6 +63,17 @@ void enable_caches(void)
 					IRAM_SIZE,
 					option);
 }
+#else
+void enable_caches(void)
+{
+	/*
+	 * Set ACTLR.SMP bit for Cortex-A7, even if the caches are
+	 * disabled by u-boot
+	 */
+	enable_ca7_smp();
+
+	puts("WARNING: Caches not enabled\n");
+}
 #endif
 
 #ifndef CONFIG_SYS_L2CACHE_OFF

arch/arm/mach-imx/mx7/soc.c +0 -7

index 3ceeeff..83bcd2d 100644
@@ -281,13 +281,6 @@ const struct boot_mode soc_boot_modes[] = {
 
 void s_init(void)
 {
-#if !defined CONFIG_SPL_BUILD
-	/* Enable SMP mode for CPU0, by setting bit 6 of Auxiliary Ctl reg */
-	asm volatile(
-			"mrc p15, 0, r0, c1, c0, 1\n"
-			"orr r0, r0, #1 << 6\n"
-			"mcr p15, 0, r0, c1, c0, 1\n");
-#endif
 	/* clock configuration. */
 	clock_init();

Signature · 1 line

2.7.4

Stefano Babic

2018-06-18 14:22 UTC #1 lore raw

PATCH 1/1 imx: Enable ACTLR.SMP bit for all i.MX cortex-a7 platforms

Quoted 94 lines · Fabio Estevam

From: Ye Li <[email protected]>

Signed-off-by Ye Li <[email protected]>

[fabio: adapted to U-Boot mainline codebase and make checkpatch happy]

Signed-off-by Fabio Estevam <[email protected]>

---
 arch/arm/mach-imx/cache.c   | 42 ++++++++++++++++++++++++++++++++++++++++++
 arch/arm/mach-imx/mx7/soc.c |  7 -------
 2 files changed, 42 insertions(+), 7 deletions(-)

arch/arm/mach-imx/cache.c +42 -0

index c5279a7..86205cf 100644
@@ -10,6 +10,34 @@
 #include <asm/io.h>
 #include <asm/mach-imx/sys_proto.h>
 
+static void enable_ca7_smp(void)
+{
+	u32 val;
+
+	/* Read MIDR */
+	asm volatile ("mrc p15, 0, %0, c0, c0, 0\n\t" : "=r"(val));
+	val = (val >> 4);
+	val &= 0xf;
+
+	/* Only set the SMP for Cortex A7 */
+	if (val == 0x7) {
+		/* Read auxiliary control register */
+		asm volatile ("mrc p15, 0, %0, c1, c0, 1\n\t" : "=r"(val));
+
+		if (val & (1 << 6))
+			return;
+
+		/* Enable SMP */
+		val |= (1 << 6);
+
+		/* Write auxiliary control register */
+		asm volatile ("mcr p15, 0, %0, c1, c0, 1\n\t" : : "r"(val));
+
+		DSB;
+		ISB;
+	}
+}
+
 #ifndef CONFIG_SYS_DCACHE_OFF
 void enable_caches(void)
 {

@@ -21,6 +49,9 @@ void enable_caches(void)
 	/* Avoid random hang when download by usb */
 	invalidate_dcache_all();
 
+	/* Set ACTLR.SMP bit for Cortex-A7 */
+	enable_ca7_smp();
+
 	/* Enable D-cache. I-cache is already enabled in start.S */
 	dcache_enable();

@@ -32,6 +63,17 @@ void enable_caches(void)
 					IRAM_SIZE,
 					option);
 }
+#else
+void enable_caches(void)
+{
+	/*
+	 * Set ACTLR.SMP bit for Cortex-A7, even if the caches are
+	 * disabled by u-boot
+	 */
+	enable_ca7_smp();
+
+	puts("WARNING: Caches not enabled\n");
+}
 #endif
 
 #ifndef CONFIG_SYS_L2CACHE_OFF

arch/arm/mach-imx/mx7/soc.c +0 -0

index 3ceeeff..83bcd2d 100644
@@ -281,13 +281,6 @@ const struct boot_mode soc_boot_modes[] = {
 
 void s_init(void)
 {

arch/arm/mach-imx/mx7/soc.c const struct boot_mode soc_boot_modes[] = { · line 286

Quoted 10 lines

arch/arm/mach-imx/mx7/soc.c +0 -7

-#if !defined CONFIG_SPL_BUILD
-	/* Enable SMP mode for CPU0, by setting bit 6 of Auxiliary Ctl reg */
-	asm volatile(
-			"mrc p15, 0, r0, c1, c0, 1\n"
-			"orr r0, r0, #1 << 6\n"
-			"mcr p15, 0, r0, c1, c0, 1\n");
-#endif
 	/* clock configuration. */
 	clock_init();

Applied to u-boot-imx, thanks !

Best regards,
Stefano Babic

Signature · 5 lines

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