mx6: add support of multi-processor command

This allows u-boot to load different OS or Bare Metal application on
different cores of the i.MX6 SoC.
For example: running Android on cpu0 and a RT OS like QNX/FreeRTOS on cpu1.

Signed-off-by: Gabriel Huau <contact@huau-gabriel.fr>
Acked-by: Stefano Babic <sbabic@denx.de>

arch/arm/cpu/armv7/mx6/Makefile

@@ -10,3 +10,4 @@
 obj-y	:= soc.o clock.o
 obj-$(CONFIG_SPL_BUILD)	     += ddr.o
 obj-$(CONFIG_SECURE_BOOT)    += hab.o
+obj-$(CONFIG_MP)             += mp.o

arch/arm/cpu/armv7/mx6/mp.c

@@ -0,0 +1,87 @@
+/*
+ * (C) Copyright 2014
+ * Gabriel Huau <contact@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/sys_proto.h>
+#include <asm/arch/imx-regs.h>
+
+#define MAX_CPUS 4
+static struct src *src = (struct src *)SRC_BASE_ADDR;
+
+static uint32_t cpu_reset_mask[MAX_CPUS] = {
+	0, /* We don't really want to modify the cpu0 */
+	SRC_SCR_CORE_1_RESET_MASK,
+	SRC_SCR_CORE_2_RESET_MASK,
+	SRC_SCR_CORE_3_RESET_MASK
+};
+
+static uint32_t cpu_ctrl_mask[MAX_CPUS] = {
+	0, /* We don't really want to modify the cpu0 */
+	SRC_SCR_CORE_1_ENABLE_MASK,
+	SRC_SCR_CORE_2_ENABLE_MASK,
+	SRC_SCR_CORE_3_ENABLE_MASK
+};
+
+int cpu_reset(int nr)
+{
+	/* Software reset of the CPU N */
+	src->scr |= cpu_reset_mask[nr];
+	return 0;
+}
+
+int cpu_status(int nr)
+{
+	printf("core %d => %d\n", nr, !!(src->scr & cpu_ctrl_mask[nr]));
+	return 0;
+}
+
+int cpu_release(int nr, int argc, char *const argv[])
+{
+	uint32_t boot_addr;
+
+	boot_addr = simple_strtoul(argv[0], NULL, 16);
+
+	switch (nr) {
+	case 1:
+		src->gpr3 = boot_addr;
+		break;
+	case 2:
+		src->gpr5 = boot_addr;
+		break;
+	case 3:
+		src->gpr7 = boot_addr;
+		break;
+	default:
+		return 1;
+	}
+
+	/* CPU N is ready to start */
+	src->scr |= cpu_ctrl_mask[nr];
+
+	return 0;
+}
+
+int is_core_valid(unsigned int core)
+{
+	uint32_t nr_cores = get_nr_cpus();
+
+	if (core > nr_cores)
+		return 0;
+
+	return 1;
+}
+
+int cpu_disable(int nr)
+{
+	/* Disable the CPU N */
+	src->scr &= ~cpu_ctrl_mask[nr];
+	return 0;
+}

arch/arm/cpu/armv7/mx6/soc.c

@@ -35,6 +35,12 @@ struct scu_regs {
 	u32	fpga_rev;
 };
 
+u32 get_nr_cpus(void)
+{
+	struct scu_regs *scu = (struct scu_regs *)SCU_BASE_ADDR;
+	return readl(&scu->config) & 3;
+}
+
 u32 get_cpu_rev(void)
 {
 	struct anatop_regs *anatop = (struct anatop_regs *)ANATOP_BASE_ADDR;

arch/arm/include/asm/arch-mx6/imx-regs.h

@@ -324,6 +324,19 @@
 
 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;

arch/arm/include/asm/arch-mx6/sys_proto.h

@@ -14,6 +14,7 @@
 #define soc_rev() (get_cpu_rev() & 0xFF)
 #define is_soc_rev(rev)        (soc_rev() - rev)
 
+u32 get_nr_cpus(void);
 u32 get_cpu_rev(void);
 
 /* returns MXC_CPU_ value */

common/board_f.c

@@ -34,6 +34,9 @@
 #ifdef CONFIG_MPC5xxx
 #include <mpc5xxx.h>
 #endif
+#if (defined(CONFIG_MPC86xx) || defined(CONFIG_E500))
+#include <asm/mp.h>
+#endif
 
 #include <os.h>
 #include <post.h>
@@ -43,9 +46,6 @@
 #include <watchdog.h>
 #include <asm/errno.h>
 #include <asm/io.h>
-#ifdef CONFIG_MP
-#include <asm/mp.h>
-#endif
 #include <asm/sections.h>
 #ifdef CONFIG_X86
 #include <asm/init_helpers.h>
@@ -381,7 +381,7 @@ static int setup_dest_addr(void)
 	gd->ram_top = board_get_usable_ram_top(gd->mon_len);
 	gd->relocaddr = gd->ram_top;
 	debug("Ram top: %08lX\n", (ulong)gd->ram_top);
-#if defined(CONFIG_MP) && (defined(CONFIG_MPC86xx) || defined(CONFIG_E500))
+#if (defined(CONFIG_MPC86xx) || defined(CONFIG_E500))
 	/*
 	 * We need to make sure the location we intend to put secondary core
 	 * boot code is reserved and not used by any part of u-boot

include/configs/mx6_common.h

@@ -28,4 +28,6 @@
 #define CONFIG_SYS_PL310_BASE	L2_PL310_BASE
 #endif
 
+#define CONFIG_MP
+
 #endif