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Subject[PATCHv2 1/2] ARM: mx51: Implement code to allow mx51 to enter WFI
Date
From: Dinh Nguyen <Dinh.Nguyen@freescale.com>

Implement code for MX51 that allows the SoC to enter WFI when
arch_idle is called.

This patch is also necessary for correctly suspending the system.

Signed-off-by: Dinh Nguyen <Dinh.Nguyen@freescale.com>
---
arch/arm/mach-mx5/Makefile | 2 +-
arch/arm/mach-mx5/system.c | 84 +++++++++++++++++++++++++++++++
arch/arm/plat-mxc/include/mach/mxc.h | 9 +++
arch/arm/plat-mxc/include/mach/system.h | 6 ++-
4 files changed, 99 insertions(+), 2 deletions(-)
create mode 100644 arch/arm/mach-mx5/system.c

diff --git a/arch/arm/mach-mx5/Makefile b/arch/arm/mach-mx5/Makefile
index 0d43be9..1106acd 100644
--- a/arch/arm/mach-mx5/Makefile
+++ b/arch/arm/mach-mx5/Makefile
@@ -3,7 +3,7 @@
#

# Object file lists.
-obj-y := cpu.o mm.o clock-mx51-mx53.o devices.o
+obj-y := cpu.o mm.o clock-mx51-mx53.o devices.o system.o
obj-$(CONFIG_SOC_IMX50) += mm-mx50.o

obj-$(CONFIG_CPU_FREQ_IMX) += cpu_op-mx51.o
diff --git a/arch/arm/mach-mx5/system.c b/arch/arm/mach-mx5/system.c
new file mode 100644
index 0000000..06d306b
--- /dev/null
+++ b/arch/arm/mach-mx5/system.c
@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2011 Freescale Semiconductor, Inc. All Rights Reserved.
+ */
+
+/*
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+#include <linux/platform_device.h>
+#include <asm/io.h>
+#include <mach/hardware.h>
+#include "crm_regs.h"
+
+/* set cpu low power mode before WFI instruction. This function is called mx5 because
+ it can be used for mx50, mx51, and mx53.*/
+void mx5_cpu_lp_set(enum mxc_cpu_pwr_mode mode)
+{
+ u32 plat_lpc, arm_srpgcr, ccm_clpcr;
+ u32 empgc0, empgc1;
+ int stop_mode = 0;
+
+ /* always allow platform to issue a deep sleep mode request */
+ plat_lpc = __raw_readl(MXC_CORTEXA8_PLAT_LPC) &
+ ~(MXC_CORTEXA8_PLAT_LPC_DSM);
+ ccm_clpcr = __raw_readl(MXC_CCM_CLPCR) & ~(MXC_CCM_CLPCR_LPM_MASK);
+ arm_srpgcr = __raw_readl(MXC_SRPG_ARM_SRPGCR) & ~(MXC_SRPGCR_PCR);
+ empgc0 = __raw_readl(MXC_SRPG_EMPGC0_SRPGCR) & ~(MXC_SRPGCR_PCR);
+ empgc1 = __raw_readl(MXC_SRPG_EMPGC1_SRPGCR) & ~(MXC_SRPGCR_PCR);
+
+ switch (mode) {
+ case WAIT_CLOCKED:
+ break;
+ case WAIT_UNCLOCKED:
+ ccm_clpcr |= 0x1 << MXC_CCM_CLPCR_LPM_OFFSET;
+ break;
+ case WAIT_UNCLOCKED_POWER_OFF:
+ case STOP_POWER_OFF:
+ plat_lpc |= MXC_CORTEXA8_PLAT_LPC_DSM
+ | MXC_CORTEXA8_PLAT_LPC_DBG_DSM;
+ if (mode == WAIT_UNCLOCKED_POWER_OFF) {
+ ccm_clpcr |= 0x1 << MXC_CCM_CLPCR_LPM_OFFSET;
+ ccm_clpcr &= ~MXC_CCM_CLPCR_VSTBY;
+ ccm_clpcr &= ~MXC_CCM_CLPCR_SBYOS;
+ stop_mode = 0;
+ } else {
+ ccm_clpcr |= 0x2 << MXC_CCM_CLPCR_LPM_OFFSET;
+ ccm_clpcr |= 0x3 << MXC_CCM_CLPCR_STBY_COUNT_OFFSET;
+ ccm_clpcr |= MXC_CCM_CLPCR_VSTBY;
+ ccm_clpcr |= MXC_CCM_CLPCR_SBYOS;
+ stop_mode = 1;
+ }
+
+ arm_srpgcr |= MXC_SRPGCR_PCR;
+ if (stop_mode) {
+ empgc0 |= MXC_SRPGCR_PCR;
+ empgc1 |= MXC_SRPGCR_PCR;
+ }
+
+ if (tzic_enable_wake(1) != 0)
+ return;
+ break;
+ case STOP_POWER_ON:
+ ccm_clpcr |= 0x2 << MXC_CCM_CLPCR_LPM_OFFSET;
+ break;
+ default:
+ printk(KERN_WARNING "UNKNOWN cpu power mode: %d\n", mode);
+ return;
+ }
+
+ __raw_writel(plat_lpc, MXC_CORTEXA8_PLAT_LPC);
+ __raw_writel(ccm_clpcr, MXC_CCM_CLPCR);
+ __raw_writel(arm_srpgcr, MXC_SRPG_ARM_SRPGCR);
+ /* Enable NEON SRPG for all but MX50TO1.0. */
+ __raw_writel(arm_srpgcr, MXC_SRPG_NEON_SRPGCR);
+ if (stop_mode) {
+ __raw_writel(empgc0, MXC_SRPG_EMPGC0_SRPGCR);
+ __raw_writel(empgc1, MXC_SRPG_EMPGC1_SRPGCR);
+ }
+}
+
diff --git a/arch/arm/plat-mxc/include/mach/mxc.h b/arch/arm/plat-mxc/include/mach/mxc.h
index 04c7a26..8a8970d 100644
--- a/arch/arm/plat-mxc/include/mach/mxc.h
+++ b/arch/arm/plat-mxc/include/mach/mxc.h
@@ -181,6 +181,15 @@ struct cpu_op {
u32 cpu_rate;
};

+int tzic_enable_wake(int is_idle);
+enum mxc_cpu_pwr_mode {
+ WAIT_CLOCKED, /* wfi only */
+ WAIT_UNCLOCKED, /* WAIT */
+ WAIT_UNCLOCKED_POWER_OFF, /* WAIT + SRPG */
+ STOP_POWER_ON, /* just STOP */
+ STOP_POWER_OFF, /* STOP + SRPG */
+};
+
extern struct cpu_op *(*get_cpu_op)(int *op);
#endif

diff --git a/arch/arm/plat-mxc/include/mach/system.h b/arch/arm/plat-mxc/include/mach/system.h
index 95be51b..35283a4 100644
--- a/arch/arm/plat-mxc/include/mach/system.h
+++ b/arch/arm/plat-mxc/include/mach/system.h
@@ -20,6 +20,8 @@
#include <mach/hardware.h>
#include <mach/common.h>

+extern void mx5_cpu_lp_set(enum mxc_cpu_pwr_mode mode);
+
static inline void arch_idle(void)
{
#ifdef CONFIG_ARCH_MXC91231
@@ -54,7 +56,9 @@ static inline void arch_idle(void)
"orr %0, %0, #0x00000004\n"
"mcr p15, 0, %0, c1, c0, 0\n"
: "=r" (reg));
- } else
+ } else if (cpu_is_mx51())
+ mx5_cpu_lp_set(WAIT_UNCLOCKED_POWER_OFF);
+ else
cpu_do_idle();
}

--
1.6.0.4



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