ARM: imx53: Set DDR pins to high impedance when in suspend to RAM.
authorMartin Fuzzey <mfuzzey@parkeon.com>
Tue, 12 May 2015 13:31:03 +0000 (15:31 +0200)
committerShawn Guo <shawn.guo@linaro.org>
Wed, 3 Jun 2015 06:49:36 +0000 (14:49 +0800)
In order to save power the DDR pins should be put into high
impedance when in suspend to RAM.

This requires manually requesting self refresh (rather than using the
automatic mode implemented by the CCM / ESDCTL), followed by
reconfiguring the IOMUXC.

Of course the code to do this cannot itself run from DDR so the
code is copied to and executed from internal memory.

In my tests using a custom i.MX53 board with LPDDR2 RAM
this reduced the suspend power consumption from 200mW to 60mW.

Signed-off-by: Martin Fuzzey <mfuzzey@parkeon.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
arch/arm/mach-imx/Makefile
arch/arm/mach-imx/common.h
arch/arm/mach-imx/pm-imx5.c
arch/arm/mach-imx/suspend-imx53.S [new file with mode: 0644]

index 40df12a..799e65a 100644 (file)
@@ -90,6 +90,7 @@ obj-$(CONFIG_SOC_IMX7D) += mach-imx7d.o
 ifeq ($(CONFIG_SUSPEND),y)
 AFLAGS_suspend-imx6.o :=-Wa,-march=armv7-a
 obj-$(CONFIG_SOC_IMX6) += suspend-imx6.o
+obj-$(CONFIG_SOC_IMX53) += suspend-imx53.o
 endif
 obj-$(CONFIG_SOC_IMX6) += pm-imx6.o
 
index 1f800b9..21e4e86 100644 (file)
@@ -116,9 +116,13 @@ int imx_cpu_kill(unsigned int cpu);
 
 #ifdef CONFIG_SUSPEND
 void v7_cpu_resume(void);
+void imx53_suspend(void __iomem *ocram_vbase);
+extern const u32 imx53_suspend_sz;
 void imx6_suspend(void __iomem *ocram_vbase);
 #else
 static inline void v7_cpu_resume(void) {}
+static inline void imx53_suspend(void __iomem *ocram_vbase) {}
+static const u32 imx53_suspend_sz;
 static inline void imx6_suspend(void __iomem *ocram_vbase) {}
 #endif
 
index b040255..a8d00b9 100644 (file)
 #include <linux/io.h>
 #include <linux/err.h>
 #include <linux/export.h>
+
+#include <linux/genalloc.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+
 #include <asm/cacheflush.h>
+#include <asm/fncpy.h>
 #include <asm/system_misc.h>
 #include <asm/tlbflush.h>
 
  */
 #define IMX5_DEFAULT_CPU_IDLE_STATE WAIT_UNCLOCKED_POWER_OFF
 
+struct imx5_suspend_io_state {
+       u32     offset;
+       u32     clear;
+       u32     set;
+       u32     saved_value;
+};
+
 struct imx5_pm_data {
        phys_addr_t ccm_addr;
        phys_addr_t cortex_addr;
        phys_addr_t gpc_addr;
+       phys_addr_t m4if_addr;
+       phys_addr_t iomuxc_addr;
+       void (*suspend_asm)(void __iomem *ocram_vbase);
+       const u32 *suspend_asm_sz;
+       const struct imx5_suspend_io_state *suspend_io_config;
+       int suspend_io_count;
+};
+
+static const struct imx5_suspend_io_state imx53_suspend_io_config[] = {
+#define MX53_DSE_HIGHZ_MASK (0x7 << 19)
+       {.offset = 0x584, .clear = MX53_DSE_HIGHZ_MASK}, /* DQM0 */
+       {.offset = 0x594, .clear = MX53_DSE_HIGHZ_MASK}, /* DQM1 */
+       {.offset = 0x560, .clear = MX53_DSE_HIGHZ_MASK}, /* DQM2 */
+       {.offset = 0x554, .clear = MX53_DSE_HIGHZ_MASK}, /* DQM3 */
+       {.offset = 0x574, .clear = MX53_DSE_HIGHZ_MASK}, /* CAS */
+       {.offset = 0x588, .clear = MX53_DSE_HIGHZ_MASK}, /* RAS */
+       {.offset = 0x578, .clear = MX53_DSE_HIGHZ_MASK}, /* SDCLK_0 */
+       {.offset = 0x570, .clear = MX53_DSE_HIGHZ_MASK}, /* SDCLK_1 */
+
+       {.offset = 0x580, .clear = MX53_DSE_HIGHZ_MASK}, /* SDODT0 */
+       {.offset = 0x564, .clear = MX53_DSE_HIGHZ_MASK}, /* SDODT1 */
+       {.offset = 0x57c, .clear = MX53_DSE_HIGHZ_MASK}, /* SDQS0 */
+       {.offset = 0x590, .clear = MX53_DSE_HIGHZ_MASK}, /* SDQS1 */
+       {.offset = 0x568, .clear = MX53_DSE_HIGHZ_MASK}, /* SDQS2 */
+       {.offset = 0x558, .clear = MX53_DSE_HIGHZ_MASK}, /* SDSQ3 */
+       {.offset = 0x6f0, .clear = MX53_DSE_HIGHZ_MASK}, /* GRP_ADDS */
+       {.offset = 0x718, .clear = MX53_DSE_HIGHZ_MASK}, /* GRP_BODS */
+       {.offset = 0x71c, .clear = MX53_DSE_HIGHZ_MASK}, /* GRP_B1DS */
+       {.offset = 0x728, .clear = MX53_DSE_HIGHZ_MASK}, /* GRP_B2DS */
+       {.offset = 0x72c, .clear = MX53_DSE_HIGHZ_MASK}, /* GRP_B3DS */
+
+       /* Controls the CKE signal which is required to leave self refresh */
+       {.offset = 0x720, .clear = MX53_DSE_HIGHZ_MASK, .set = 1 << 19}, /* CTLDS */
 };
 
 static const struct imx5_pm_data imx51_pm_data __initconst = {
@@ -65,11 +112,35 @@ static const struct imx5_pm_data imx53_pm_data __initconst = {
        .ccm_addr = 0x53fd4000,
        .cortex_addr = 0x63fa0000,
        .gpc_addr = 0x53fd8000,
+       .m4if_addr = 0x63fd8000,
+       .iomuxc_addr = 0x53fa8000,
+       .suspend_asm = &imx53_suspend,
+       .suspend_asm_sz = &imx53_suspend_sz,
+       .suspend_io_config = imx53_suspend_io_config,
+       .suspend_io_count = ARRAY_SIZE(imx53_suspend_io_config),
 };
 
+#define MX5_MAX_SUSPEND_IOSTATE ARRAY_SIZE(imx53_suspend_io_config)
+
+/*
+ * This structure is for passing necessary data for low level ocram
+ * suspend code(arch/arm/mach-imx/suspend-imx53.S), if this struct
+ * definition is changed, the offset definition in that file
+ * must be also changed accordingly otherwise, the suspend to ocram
+ * function will be broken!
+ */
+struct imx5_cpu_suspend_info {
+       void __iomem    *m4if_base;
+       void __iomem    *iomuxc_base;
+       u32             io_count;
+       struct imx5_suspend_io_state io_state[MX5_MAX_SUSPEND_IOSTATE];
+} __aligned(8);
+
 static void __iomem *ccm_base;
 static void __iomem *cortex_base;
 static void __iomem *gpc_base;
+static void __iomem *suspend_ocram_base;
+static void (*imx5_suspend_in_ocram_fn)(void __iomem *ocram_vbase);
 
 /*
  * set cpu low power mode before WFI instruction. This function is called
@@ -159,8 +230,15 @@ static int mx5_suspend_enter(suspend_state_t state)
                /*clear the EMPGC0/1 bits */
                __raw_writel(0, gpc_base + MXC_SRPG_EMPGC0_SRPGCR);
                __raw_writel(0, gpc_base + MXC_SRPG_EMPGC1_SRPGCR);
+
+               if (imx5_suspend_in_ocram_fn)
+                       imx5_suspend_in_ocram_fn(suspend_ocram_base);
+               else
+                       cpu_do_idle();
+
+       } else {
+               cpu_do_idle();
        }
-       cpu_do_idle();
 
        /* return registers to default idle state */
        mx5_cpu_lp_set(IMX5_DEFAULT_CPU_IDLE_STATE);
@@ -192,6 +270,111 @@ static void imx5_pm_idle(void)
        imx5_cpu_do_idle();
 }
 
+static int __init imx_suspend_alloc_ocram(
+                               size_t size,
+                               void __iomem **virt_out,
+                               phys_addr_t *phys_out)
+{
+       struct device_node *node;
+       struct platform_device *pdev;
+       struct gen_pool *ocram_pool;
+       unsigned long ocram_base;
+       void __iomem *virt;
+       phys_addr_t phys;
+       int ret = 0;
+
+       /* Copied from imx6: TODO factorize */
+       node = of_find_compatible_node(NULL, NULL, "mmio-sram");
+       if (!node) {
+               pr_warn("%s: failed to find ocram node!\n", __func__);
+               return -ENODEV;
+       }
+
+       pdev = of_find_device_by_node(node);
+       if (!pdev) {
+               pr_warn("%s: failed to find ocram device!\n", __func__);
+               ret = -ENODEV;
+               goto put_node;
+       }
+
+       ocram_pool = dev_get_gen_pool(&pdev->dev);
+       if (!ocram_pool) {
+               pr_warn("%s: ocram pool unavailable!\n", __func__);
+               ret = -ENODEV;
+               goto put_node;
+       }
+
+       ocram_base = gen_pool_alloc(ocram_pool, size);
+       if (!ocram_base) {
+               pr_warn("%s: unable to alloc ocram!\n", __func__);
+               ret = -ENOMEM;
+               goto put_node;
+       }
+
+       phys = gen_pool_virt_to_phys(ocram_pool, ocram_base);
+       virt = __arm_ioremap_exec(phys, size, false);
+       if (phys_out)
+               *phys_out = phys;
+       if (virt_out)
+               *virt_out = virt;
+
+put_node:
+       of_node_put(node);
+
+       return ret;
+}
+
+static int __init imx5_suspend_init(const struct imx5_pm_data *soc_data)
+{
+       struct imx5_cpu_suspend_info *suspend_info;
+       int ret;
+       /* Need this to avoid compile error due to const typeof in fncpy.h */
+       void (*suspend_asm)(void __iomem *) = soc_data->suspend_asm;
+
+       if (!suspend_asm)
+               return 0;
+
+       if (!soc_data->suspend_asm_sz || !*soc_data->suspend_asm_sz)
+               return -EINVAL;
+
+       ret = imx_suspend_alloc_ocram(
+               *soc_data->suspend_asm_sz + sizeof(*suspend_info),
+               &suspend_ocram_base, NULL);
+       if (ret)
+               return ret;
+
+       suspend_info = suspend_ocram_base;
+
+       suspend_info->io_count = soc_data->suspend_io_count;
+       memcpy(suspend_info->io_state, soc_data->suspend_io_config,
+              sizeof(*suspend_info->io_state) * soc_data->suspend_io_count);
+
+       suspend_info->m4if_base = ioremap(soc_data->m4if_addr, SZ_16K);
+       if (!suspend_info->m4if_base) {
+               ret = -ENOMEM;
+               goto failed_map_m4if;
+       }
+
+       suspend_info->iomuxc_base = ioremap(soc_data->iomuxc_addr, SZ_16K);
+       if (!suspend_info->iomuxc_base) {
+               ret = -ENOMEM;
+               goto failed_map_iomuxc;
+       }
+
+       imx5_suspend_in_ocram_fn = fncpy(
+               suspend_ocram_base + sizeof(*suspend_info),
+               suspend_asm,
+               *soc_data->suspend_asm_sz);
+
+       return 0;
+
+failed_map_iomuxc:
+       iounmap(suspend_info->m4if_base);
+
+failed_map_m4if:
+       return ret;
+}
+
 static int __init imx5_pm_common_init(const struct imx5_pm_data *data)
 {
        int ret;
@@ -218,6 +401,11 @@ static int __init imx5_pm_common_init(const struct imx5_pm_data *data)
        if (ret)
                pr_warn("%s: cpuidle init failed %d\n", __func__, ret);
 
+       ret = imx5_suspend_init(data);
+       if (ret)
+               pr_warn("%s: No DDR LPM support with suspend %d!\n",
+                       __func__, ret);
+
        suspend_set_ops(&mx5_suspend_ops);
 
        return 0;
diff --git a/arch/arm/mach-imx/suspend-imx53.S b/arch/arm/mach-imx/suspend-imx53.S
new file mode 100644 (file)
index 0000000..5ed078a
--- /dev/null
@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 2008-2011 Freescale Semiconductor, Inc.
+ */
+/*
+ * 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/linkage.h>
+
+#define M4IF_MCR0_OFFSET                       (0x008C)
+#define M4IF_MCR0_FDVFS                                (0x1 << 11)
+#define M4IF_MCR0_FDVACK                       (0x1 << 27)
+
+       .align 3
+
+/*
+ * ==================== low level suspend ====================
+ *
+ * On entry
+ * r0: pm_info structure address;
+ *
+ * suspend ocram space layout:
+ * ======================== high address ======================
+ *                              .
+ *                              .
+ *                              .
+ *                              ^
+ *                              ^
+ *                              ^
+ *                      imx53_suspend code
+ *              PM_INFO structure(imx53_suspend_info)
+ * ======================== low address =======================
+ */
+
+/* Offsets of members of struct imx53_suspend_info */
+#define SUSPEND_INFO_MX53_M4IF_V_OFFSET                0x0
+#define SUSPEND_INFO_MX53_IOMUXC_V_OFFSET      0x4
+#define SUSPEND_INFO_MX53_IO_COUNT_OFFSET      0x8
+#define SUSPEND_INFO_MX53_IO_STATE_OFFSET      0xc
+
+ENTRY(imx53_suspend)
+       stmfd   sp!, {r4,r5,r6,r7}
+
+       /* Save pad config */
+       ldr     r1, [r0, #SUSPEND_INFO_MX53_IO_COUNT_OFFSET]
+       cmp     r1, #0
+       beq     skip_pad_conf_1
+
+       add     r2, r0, #SUSPEND_INFO_MX53_IO_STATE_OFFSET
+       ldr     r3, [r0, #SUSPEND_INFO_MX53_IOMUXC_V_OFFSET]
+
+1:
+       ldr     r5, [r2], #12   /* IOMUXC register offset */
+       ldr     r6, [r3, r5]    /* current value */
+       str     r6, [r2], #4    /* save area */
+       subs    r1, r1, #1
+       bne     1b
+
+skip_pad_conf_1:
+       /* Set FDVFS bit of M4IF_MCR0 to request DDR to enter self-refresh */
+       ldr     r1, [r0, #SUSPEND_INFO_MX53_M4IF_V_OFFSET]
+       ldr     r2,[r1, #M4IF_MCR0_OFFSET]
+       orr     r2, r2, #M4IF_MCR0_FDVFS
+       str     r2,[r1, #M4IF_MCR0_OFFSET]
+
+       /* Poll FDVACK bit of M4IF_MCR to wait for DDR to enter self-refresh */
+wait_sr_ack:
+       ldr     r2,[r1, #M4IF_MCR0_OFFSET]
+       ands    r2, r2, #M4IF_MCR0_FDVACK
+       beq     wait_sr_ack
+
+       /* Set pad config */
+       ldr     r1, [r0, #SUSPEND_INFO_MX53_IO_COUNT_OFFSET]
+       cmp     r1, #0
+       beq     skip_pad_conf_2
+
+       add     r2, r0, #SUSPEND_INFO_MX53_IO_STATE_OFFSET
+       ldr     r3, [r0, #SUSPEND_INFO_MX53_IOMUXC_V_OFFSET]
+
+2:
+       ldr     r5, [r2], #4    /* IOMUXC register offset */
+       ldr     r6, [r2], #4    /* clear */
+       ldr     r7, [r3, r5]
+       bic     r7, r7, r6
+       ldr     r6, [r2], #8    /* set */
+       orr     r7, r7, r6
+       str     r7, [r3, r5]
+       subs    r1, r1, #1
+       bne     2b
+
+skip_pad_conf_2:
+       /* Zzz, enter stop mode */
+       wfi
+       nop
+       nop
+       nop
+       nop
+
+       /* Restore pad config */
+       ldr     r1, [r0, #SUSPEND_INFO_MX53_IO_COUNT_OFFSET]
+       cmp     r1, #0
+       beq     skip_pad_conf_3
+
+       add     r2, r0, #SUSPEND_INFO_MX53_IO_STATE_OFFSET
+       ldr     r3, [r0, #SUSPEND_INFO_MX53_IOMUXC_V_OFFSET]
+
+3:
+       ldr     r5, [r2], #12   /* IOMUXC register offset */
+       ldr     r6, [r2], #4    /* saved value */
+       str     r6, [r3, r5]
+       subs    r1, r1, #1
+       bne     3b
+
+skip_pad_conf_3:
+       /* Clear FDVFS bit of M4IF_MCR0 to request DDR to exit self-refresh */
+       ldr     r1, [r0, #SUSPEND_INFO_MX53_M4IF_V_OFFSET]
+       ldr     r2,[r1, #M4IF_MCR0_OFFSET]
+       bic     r2, r2, #M4IF_MCR0_FDVFS
+       str     r2,[r1, #M4IF_MCR0_OFFSET]
+
+       /* Poll FDVACK bit of M4IF_MCR to wait for DDR to exit self-refresh */
+wait_ar_ack:
+       ldr     r2,[r1, #M4IF_MCR0_OFFSET]
+       ands    r2, r2, #M4IF_MCR0_FDVACK
+       bne     wait_ar_ack
+
+       /* Restore registers */
+       ldmfd   sp!, {r4,r5,r6,r7}
+       mov     pc, lr
+
+ENDPROC(imx53_suspend)
+
+ENTRY(imx53_suspend_sz)
+        .word   . - imx53_suspend