[U-Boot] [PATCH v3] mx6: add support of multi-processor command

[Gabriel Huau]

This allows u-boot to load different OS or Bare Metal application on the
different cores of the i.MX6DQ.
For example: we can run Android on cpu0 and a RT OS like QNX/FreeRTOS on cpu1.

Signed-off-by: Gabriel Huau <contact at huau-gabriel.fr>
---
Changes for v2:
	- Add a commit log message to explain the purpose of this patch
Changes for v3:
	- Remove unnecessary check for unsigned values when they are negative

 arch/arm/cpu/armv7/mx6/Makefile          |   1 +
 arch/arm/cpu/armv7/mx6/mp.c              | 131 +++++++++++++++++++++++++++++++
 arch/arm/include/asm/arch-mx6/imx-regs.h |  13 +++
 3 files changed, 145 insertions(+)
 create mode 100644 arch/arm/cpu/armv7/mx6/mp.c

diff --git a/arch/arm/cpu/armv7/mx6/Makefile b/arch/arm/cpu/armv7/mx6/Makefile
index d7285fc..ec08526 100644
--- a/arch/arm/cpu/armv7/mx6/Makefile
+++ b/arch/arm/cpu/armv7/mx6/Makefile
@@ -9,3 +9,4 @@
 
 obj-y	:= soc.o clock.o
 obj-$(CONFIG_SECURE_BOOT)    += hab.o
+obj-$(CONFIG_MP)             += mp.o
diff --git a/arch/arm/cpu/armv7/mx6/mp.c b/arch/arm/cpu/armv7/mx6/mp.c
new file mode 100644
index 0000000..8105fcc
--- /dev/null
+++ b/arch/arm/cpu/armv7/mx6/mp.c
@@ -0,0 +1,131 @@
+/*
+ * (C) Copyright 2014
+ * Gabriel Huau <contact at huau-gabriel.fr>
+ *
+ * (C) Copyright 2009 Freescale Semiconductor, Inc.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/errno.h>
+#include <asm/arch/imx-regs.h>
+
+int cpu_reset(int nr)
+{
+	uint32_t reg;
+	struct src *src = (struct src *)SRC_BASE_ADDR;
+
+	reg = __raw_readl(&src->scr);
+
+	switch (nr) {
+	case 1:
+		reg |= SRC_SCR_CORE_1_RESET_MASK;
+		break;
+
+	case 2:
+		reg |= SRC_SCR_CORE_2_RESET_MASK;
+		break;
+
+	case 3:
+		reg |= SRC_SCR_CORE_3_RESET_MASK;
+		break;
+	}
+
+	/* Software reset of the CPU N */
+	__raw_writel(reg, &src->scr);
+
+	return 0;
+}
+
+int cpu_status(int nr)
+{
+	uint32_t reg;
+	struct src *src = (struct src *)SRC_BASE_ADDR;
+
+	reg = __raw_readl(&src->scr);
+
+	switch (nr) {
+	case 1:
+		printf("core 1: %d\n", !!(reg & SRC_SCR_CORE_1_ENABLE_MASK));
+		break;
+
+	case 2:
+		printf("core 2: %d\n", !!(reg & SRC_SCR_CORE_2_ENABLE_MASK));
+		break;
+
+	case 3:
+		printf("core 3: %d\n", !!(reg & SRC_SCR_CORE_3_ENABLE_MASK));
+		break;
+	}
+
+	return 0;
+}
+
+int cpu_release(int nr, int argc, char *const argv[])
+{
+	uint32_t reg;
+	struct src *src = (struct src *)SRC_BASE_ADDR;
+	uint32_t boot_addr;
+
+	boot_addr = simple_strtoul(argv[0], NULL, 16);
+	reg = __raw_readl(&src->scr);
+
+	switch (nr) {
+	case 1:
+		__raw_writel(boot_addr, &src->gpr3);
+		reg |= SRC_SCR_CORE_1_ENABLE_MASK;
+		break;
+
+	case 2:
+		__raw_writel(boot_addr, &src->gpr5);
+		reg |= SRC_SCR_CORE_2_ENABLE_MASK;
+		break;
+
+	case 3:
+		__raw_writel(boot_addr, &src->gpr7);
+		reg |= SRC_SCR_CORE_3_ENABLE_MASK;
+		break;
+	}
+
+	/* CPU N is ready to start */
+	__raw_writel(reg, &src->scr);
+
+	return 0;
+}
+
+int is_core_valid(unsigned int nr)
+{
+	if (nr >= CONFIG_NUM_CPUS)
+		return 0;
+
+	return 1;
+}
+
+int cpu_disable(int nr)
+{
+	uint32_t reg;
+	struct src *src = (struct src *)SRC_BASE_ADDR;
+
+	reg = __raw_readl(&src->scr);
+
+	switch (nr) {
+	case 1:
+		reg &= ~SRC_SCR_CORE_1_ENABLE_MASK;
+		break;
+
+	case 2:
+		reg &= ~SRC_SCR_CORE_2_ENABLE_MASK;
+		break;
+
+	case 3:
+		reg &= ~SRC_SCR_CORE_3_ENABLE_MASK;
+		break;
+	}
+
+	/* Disable the CPU N */
+	__raw_writel(reg, &src->scr);
+
+	return 0;
+}
diff --git a/arch/arm/include/asm/arch-mx6/imx-regs.h b/arch/arm/include/asm/arch-mx6/imx-regs.h
index 1f19727..3f8c2ee 100644
--- a/arch/arm/include/asm/arch-mx6/imx-regs.h
+++ b/arch/arm/include/asm/arch-mx6/imx-regs.h
@@ -225,6 +225,19 @@
 
 extern void imx_get_mac_from_fuse(int dev_id, unsigned char *mac);
 
+#define SRC_SCR_CORE_1_RESET_OFFSET     14
+#define SRC_SCR_CORE_1_RESET_MASK       (1<<SRC_SCR_CORE_1_RESET_OFFSET)
+#define SRC_SCR_CORE_2_RESET_OFFSET     15
+#define SRC_SCR_CORE_2_RESET_MASK       (1<<SRC_SCR_CORE_2_RESET_OFFSET)
+#define SRC_SCR_CORE_3_RESET_OFFSET     16
+#define SRC_SCR_CORE_3_RESET_MASK       (1<<SRC_SCR_CORE_3_RESET_OFFSET)
+#define SRC_SCR_CORE_1_ENABLE_OFFSET    22
+#define SRC_SCR_CORE_1_ENABLE_MASK      (1<<SRC_SCR_CORE_1_ENABLE_OFFSET)
+#define SRC_SCR_CORE_2_ENABLE_OFFSET    23
+#define SRC_SCR_CORE_2_ENABLE_MASK      (1<<SRC_SCR_CORE_2_ENABLE_OFFSET)
+#define SRC_SCR_CORE_3_ENABLE_OFFSET    24
+#define SRC_SCR_CORE_3_ENABLE_MASK      (1<<SRC_SCR_CORE_3_ENABLE_OFFSET)
+
 /* System Reset Controller (SRC) */
 struct src {
 	u32	scr;
-- 
2.0.0