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>

4 files changed, 99 insertions, 2 deletions

diff --git a/arch/arm/mach-mx5/Makefile b/arch/arm/mach-mx5/Makefile
index 4f63048be3ca..0b9338cec516 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 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
diff --git a/arch/arm/mach-mx5/system.c b/arch/arm/mach-mx5/system.c
new file mode 100644
index 000000000000..76ae8dc33e00
--- /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 <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);
+        }
+}
diff --git a/arch/arm/plat-mxc/include/mach/mxc.h b/arch/arm/plat-mxc/include/mach/mxc.h
index 3322c7a79c57..1aea818d9d31 100644
--- a/arch/arm/plat-mxc/include/mach/mxc.h
+++ b/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
 
diff --git a/arch/arm/plat-mxc/include/mach/system.h b/arch/arm/plat-mxc/include/mach/system.h
index 95be51bfe9a9..0417da9f710d 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();
 }