ARM: mx51: Implement code to allow mx51 to enter WFI

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>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

arch/arm/mach-mx5/Makefile

@@ -3,7 +3,7 @@
 #
 
 # Object file lists.
-obj-y   := cpu.o mm.o clock-mx51-mx53.o devices.o ehci.o
+obj-y   := cpu.o mm.o clock-mx51-mx53.o devices.o ehci.o system.o
 obj-$(CONFIG_SOC_IMX50) += mm-mx50.o
 
 obj-$(CONFIG_CPU_FREQ_IMX)    += cpu_op-mx51.o

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 <linux/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 (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. */
+	if (mx50_revision() != IMX_CHIP_REVISION_1_0)
+		__raw_writel(arm_srpgcr, MXC_SRPG_NEON_SRPGCR);
+
+	if (stop_mode) {
+		empgc0 |= MXC_SRPGCR_PCR;
+		empgc1 |= MXC_SRPGCR_PCR;
+
+		__raw_writel(empgc0, MXC_SRPG_EMPGC0_SRPGCR);
+		__raw_writel(empgc1, MXC_SRPG_EMPGC1_SRPGCR);
+	}
+}

arch/arm/plat-mxc/include/mach/mxc.h

@@ -195,6 +195,15 @@ 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
 

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();
 }