[U-Boot] [PATCH 02/11] Exynos542x: CPU: Power down all secondary cores
Akshay Saraswat
akshay.s at samsung.com
Thu Jan 15 14:41:59 CET 2015
This patch adds code to shutdown secondary cores.
When U-boot comes up, all secondary cores appear powered on,
which is undesirable and causes side effects while
initializing these cores in kernel.
Secondary core power down happens in following steps:
Step-1: After Exynos power-on, primary core starts executing first.
Step-2: In iROM code every core has to check 2 flags i.e.
addresses 0x02020028 & 0x02020004.
Step-3: Initially 0x02020028 is 0 for all cores and 0x02020004 has a
jump address for primary core and 0 for all secondary cores.
Step-4: Therefore, primary core follows normal iROM execution and jumps
to BL1 eventually, whereas all secondary cores enter WFE.
Step-5: When primary core comes into function secondary_cores_configure,
it puts pointer to function power_down_core into 0x02020004
and provides DSB and SEV for all cores so that they may come out
of WFE and jump to power_down_core function.
Step-6: And ultimately because of power_down_core all
secondary cores shut-down.
Signed-off-by: Kimoon Kim <kimoon.kim at samsung.com>
Signed-off-by: Akshay Saraswat <akshay.s at samsung.com>
---
arch/arm/cpu/armv7/exynos/lowlevel_init.c | 62 ++++++++++++++++++++++
arch/arm/include/asm/arch-exynos/cpu.h | 30 +++++++++++
arch/arm/include/asm/arch-exynos/system.h | 87 +++++++++++++++++++++++++++++++
3 files changed, 179 insertions(+)
diff --git a/arch/arm/cpu/armv7/exynos/lowlevel_init.c b/arch/arm/cpu/armv7/exynos/lowlevel_init.c
index 83e1dcf..43c957b 100644
--- a/arch/arm/cpu/armv7/exynos/lowlevel_init.c
+++ b/arch/arm/cpu/armv7/exynos/lowlevel_init.c
@@ -31,6 +31,7 @@
#include <asm/arch/tzpc.h>
#include <asm/arch/periph.h>
#include <asm/arch/pinmux.h>
+#include <asm/arch/system.h>
#include "common_setup.h"
/* These are the things we can do during low-level init */
@@ -42,6 +43,62 @@ enum {
DO_POWER = 1 << 4,
};
+#ifdef CONFIG_EXYNOS5420
+/*
+ * Pointer to this function is stored in iRam which is used
+ * for jump and power down of a specific core.
+ */
+static void power_down_core(void)
+{
+ uint32_t tmp, core_id, core_config;
+
+ /* Get the core id */
+ mrc_mpafr(core_id);
+ tmp = core_id & 0x3;
+ core_id = (core_id >> 6) & ~3;
+ core_id |= tmp;
+
+ /* Set the status of the core to low */
+ core_config = (core_id * CORE_CONFIG_OFFSET);
+ core_config += ARM_CORE0_CONFIG;
+ writel(0x0, core_config);
+
+ /* Core enter WFI */
+ wfi();
+}
+
+/*
+ * Configurations for secondary cores are inapt at this stage.
+ * Reconfigure secondary cores. Shutdown and change the status
+ * of all cores except the primary core.
+ */
+static void secondary_cores_configure(void)
+{
+ uint32_t core_id;
+
+ /* Store jump address for power down of secondary cores */
+ writel((uint32_t)&power_down_core, CONFIG_PHY_IRAM_BASE + 0x4);
+
+ /* Need all core power down check */
+ dsb();
+ sev();
+
+ /*
+ * Power down all cores(secondary) while primary core must
+ * wait for all cores to go down.
+ */
+ for (core_id = 1; core_id != CORE_COUNT; core_id++) {
+ while ((readl(ARM_CORE0_STATUS
+ + (core_id * CORE_CONFIG_OFFSET))
+ & 0xff) != 0x0) {
+ isb();
+ sev();
+ }
+ isb();
+ }
+}
+#endif
+
int do_lowlevel_init(void)
{
uint32_t reset_status;
@@ -49,6 +106,11 @@ int do_lowlevel_init(void)
arch_cpu_init();
+#ifdef CONFIG_EXYNOS5420
+ /* Reconfigure secondary cores */
+ secondary_cores_configure();
+#endif
+
reset_status = get_reset_status();
switch (reset_status) {
diff --git a/arch/arm/include/asm/arch-exynos/cpu.h b/arch/arm/include/asm/arch-exynos/cpu.h
index 29674ad..f1f9994 100644
--- a/arch/arm/include/asm/arch-exynos/cpu.h
+++ b/arch/arm/include/asm/arch-exynos/cpu.h
@@ -177,6 +177,7 @@
#define EXYNOS5420_GPIO_PART1_BASE 0x14010000
#define EXYNOS5420_MIPI_DSIM_BASE 0x14500000
#define EXYNOS5420_DP_BASE 0x145B0000
+#define EXYNOS5420_INF_REG_BASE 0x10040800
#define EXYNOS5420_USBPHY_BASE DEVICE_NOT_AVAILABLE
#define EXYNOS5420_USBOTG_BASE DEVICE_NOT_AVAILABLE
@@ -186,6 +187,35 @@
#define EXYNOS5420_USB3PHY_BASE DEVICE_NOT_AVAILABLE
#define EXYNOS5420_USB_HOST_XHCI_BASE DEVICE_NOT_AVAILABLE
+#define ARM_CORE0_CONFIG (EXYNOS5420_POWER_BASE + 0x2000)
+#define ARM_CORE0_STATUS (EXYNOS5420_POWER_BASE + 0x2004)
+#define CORE_CONFIG_OFFSET 0x80
+#define CORE_COUNT 0x8
+
+/*
+ * POWER
+ */
+#define PMU_BASE EXYNOS5420_POWER_BASE
+#define SW_RST_REG_OFFSET 0x400
+
+#define INF_REG_BASE EXYNOS5420_INF_REG_BASE
+#define INF_REG0_OFFSET 0x00
+#define INF_REG1_OFFSET 0x04
+#define INF_REG2_OFFSET 0x08
+#define INF_REG3_OFFSET 0x0C
+#define INF_REG4_OFFSET 0x10
+#define INF_REG5_OFFSET 0x14
+#define INF_REG6_OFFSET 0x18
+#define INF_REG7_OFFSET 0x1C
+
+#define PMU_SPARE_BASE (EXYNOS5420_INF_REG_BASE + 0x100)
+#define PMU_SPARE_0 PMU_SPARE_BASE
+#define PMU_SPARE_1 (PMU_SPARE_BASE + 0x4)
+#define PMU_SPARE_2 (PMU_SPARE_BASE + 0x8)
+#define PMU_SPARE_3 (PMU_SPARE_BASE + 0xc)
+#define RST_FLAG_REG PMU_SPARE_BASE
+#define RST_FLAG_VAL 0xfcba0d10
+
#ifndef __ASSEMBLY__
#include <asm/io.h>
/* CPU detection macros */
diff --git a/arch/arm/include/asm/arch-exynos/system.h b/arch/arm/include/asm/arch-exynos/system.h
index 4968d3d..86903c3 100644
--- a/arch/arm/include/asm/arch-exynos/system.h
+++ b/arch/arm/include/asm/arch-exynos/system.h
@@ -37,6 +37,93 @@ struct exynos5_sysreg {
#define USB20_PHY_CFG_HOST_LINK_EN (1 << 0)
+#ifdef CONFIG_EXYNOS5420
+/*
+ * Data Synchronization Barrier acts as a special kind of memory barrier.
+ * No instruction in program order after this instruction executes until
+ * this instruction completes. This instruction completes when:
+ * - All explicit memory accesses before this instruction complete.
+ * - All Cache, Branch predictor and TLB maintenance operations before
+ * this instruction complete.
+ */
+#define dsb() __asm__ __volatile__ ("dsb\n\t" : : );
+
+/*
+ * This instruction causes an event to be signaled to all cores
+ * within a multiprocessor system. If SEV is implemented,
+ * WFE must also be implemented.
+ */
+#define sev() __asm__ __volatile__ ("sev\n\t" : : );
+/*
+ * If the Event Register is not set, WFE suspends execution until
+ * one of the following events occurs:
+ * - an IRQ interrupt, unless masked by the CPSR I-bit
+ * - an FIQ interrupt, unless masked by the CPSR F-bit
+ * - an Imprecise Data abort, unless masked by the CPSR A-bit
+ * - a Debug Entry request, if Debug is enabled
+ * - an Event signaled by another processor using the SEV instruction.
+ * If the Event Register is set, WFE clears it and returns immediately.
+ * If WFE is implemented, SEV must also be implemented.
+ */
+#define wfe() __asm__ __volatile__ ("wfe\n\t" : : );
+
+/* Move 0xd3 value to CPSR register to enable SVC mode */
+#define svc32_mode_en() __asm__ __volatile__ \
+ ("@ I&F disable, Mode: 0x13 - SVC\n\t" \
+ "msr cpsr_c, #0x13|0xC0\n\t" : : )
+
+/* Set program counter with the given value */
+#define set_pc(x) __asm__ __volatile__ ("mov pc, %0\n\t" : : "r"(x))
+
+/* Read Main Id register */
+#define mrc_midr(x) __asm__ __volatile__ \
+ ("mrc p15, 0, %0, c0, c0, 0\n\t" : "=r"(x) : )
+
+/* Read Multiprocessor Affinity Register */
+#define mrc_mpafr(x) __asm__ __volatile__ \
+ ("mrc p15, 0, %0, c0, c0, 5\n\t" : "=r"(x) : )
+
+/* Read System Control Register */
+#define mrc_sctlr(x) __asm__ __volatile__ \
+ ("mrc p15, 0, %0, c1, c0, 0\n\t" : "=r"(x) : )
+
+/* Read Auxiliary Control Register */
+#define mrc_auxr(x) __asm__ __volatile__ \
+ ("mrc p15, 0, %0, c1, c0, 1\n\t" : "=r"(x) : )
+
+/* Read L2 Control register */
+#define mrc_l2_ctlr(x) __asm__ __volatile__ \
+ ("mrc p15, 1, %0, c9, c0, 2\n\t" : "=r"(x) : )
+
+/* Read L2 Auxilliary Control register */
+#define mrc_l2_aux_ctlr(x) __asm__ __volatile__ \
+ ("mrc p15, 1, %0, c15, c0, 0\n\t" : "=r"(x) : )
+
+/* Write System Control Register */
+#define mcr_sctlr(x) __asm__ __volatile__ \
+ ("mcr p15, 0, %0, c1, c0, 0\n\t" : : "r"(x))
+
+/* Write Auxiliary Control Register */
+#define mcr_auxr(x) __asm__ __volatile__ \
+ ("mcr p15, 0, %0, c1, c0, 1\n\t" : : "r"(x))
+
+/* Invalidate all instruction caches to PoU */
+#define mcr_icache(x) __asm__ __volatile__ \
+ ("mcr p15, 0, %0, c7, c5, 0\n\t" : : "r"(x))
+
+/* Invalidate unified TLB */
+#define mcr_tlb(x) __asm__ __volatile__ \
+ ("mcr p15, 0, %0, c8, c7, 0\n\t" : : "r"(x))
+
+/* Write L2 Control register */
+#define mcr_l2_ctlr(x) __asm__ __volatile__ \
+ ("mcr p15, 1, %0, c9, c0, 2\n\t" : : "r"(x))
+
+/* Write L2 Auxilliary Control register */
+#define mcr_l2_aux_ctlr(x) __asm__ __volatile__ \
+ ("mcr p15, 1, %0, c15, c0, 0\n\t" : : "r"(x))
+#endif
+
void set_usbhost_mode(unsigned int mode);
void set_system_display_ctrl(void);
int exynos_lcd_early_init(const void *blob);
--
1.9.1
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