mtd: sh_flctl: Add power management with QoS request

Adds power management code with fine granularity. Every flash control
command is enclosed by runtime_put()/get()s. To make sure that no
overhead is generated by too frequent power state switches, a quality of
service request is issued.

Signed-off-by: Bastian Hecht <hechtb@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --git a/drivers/mtd/nand/sh_flctl.c b/drivers/mtd/nand/sh_flctl.c
index d0f1f3c..2ee9a1b 100644 (file)
--- a/drivers/mtd/nand/sh_flctl.c
+++ b/drivers/mtd/nand/sh_flctl.c
@@ -26,6 +26,7 @@
 #include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/slab.h>
 
 #include <linux/mtd/mtd.h>
@@ -515,6 +516,8 @@ static void flctl_cmdfunc(struct mtd_info *mtd, unsigned int command,
        struct sh_flctl *flctl = mtd_to_flctl(mtd);
        uint32_t read_cmd = 0;
 
+       pm_runtime_get_sync(&flctl->pdev->dev);
+
        flctl->read_bytes = 0;
        if (command != NAND_CMD_PAGEPROG)
                flctl->index = 0;
@@ -670,7 +673,7 @@ static void flctl_cmdfunc(struct mtd_info *mtd, unsigned int command,
        default:
                break;
        }
-       return;
+       goto runtime_exit;
 
 read_normal_exit:
        writel(flctl->read_bytes, FLDTCNTR(flctl));     /* set read size */
@@ -678,23 +681,47 @@ read_normal_exit:
        start_translation(flctl);
        read_fiforeg(flctl, flctl->read_bytes, 0);
        wait_completion(flctl);
+runtime_exit:
+       pm_runtime_put_sync(&flctl->pdev->dev);
        return;
 }
 
 static void flctl_select_chip(struct mtd_info *mtd, int chipnr)
 {
        struct sh_flctl *flctl = mtd_to_flctl(mtd);
+       int ret;
 
        switch (chipnr) {
        case -1:
                flctl->flcmncr_base &= ~CE0_ENABLE;
+
+               pm_runtime_get_sync(&flctl->pdev->dev);
                writel(flctl->flcmncr_base, FLCMNCR(flctl));
+
+               if (flctl->qos_request) {
+                       dev_pm_qos_remove_request(&flctl->pm_qos);
+                       flctl->qos_request = 0;
+               }
+
+               pm_runtime_put_sync(&flctl->pdev->dev);
                break;
        case 0:
                flctl->flcmncr_base |= CE0_ENABLE;
-               writel(flctl->flcmncr_base, FLCMNCR(flctl));
-               if (flctl->holden)
+
+               if (!flctl->qos_request) {
+                       ret = dev_pm_qos_add_request(&flctl->pdev->dev,
+                                                       &flctl->pm_qos, 100);
+                       if (ret < 0)
+                               dev_err(&flctl->pdev->dev,
+                                       "PM QoS request failed: %d\n", ret);
+                       flctl->qos_request = 1;
+               }
+
+               if (flctl->holden) {
+                       pm_runtime_get_sync(&flctl->pdev->dev);
                        writel(HOLDEN, FLHOLDCR(flctl));
+                       pm_runtime_put_sync(&flctl->pdev->dev);
+               }
                break;
        default:
                BUG();
@@ -835,13 +862,13 @@ static int __devinit flctl_probe(struct platform_device *pdev)
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res) {
                dev_err(&pdev->dev, "failed to get I/O memory\n");
-               goto err;
+               goto err_iomap;
        }
 
        flctl->reg = ioremap(res->start, resource_size(res));
        if (flctl->reg == NULL) {
                dev_err(&pdev->dev, "failed to remap I/O memory\n");
-               goto err;
+               goto err_iomap;
        }
 
        platform_set_drvdata(pdev, flctl);
@@ -871,23 +898,28 @@ static int __devinit flctl_probe(struct platform_device *pdev)
                nand->read_word = flctl_read_word;
        }
 
+       pm_runtime_enable(&pdev->dev);
+       pm_runtime_resume(&pdev->dev);
+
        ret = nand_scan_ident(flctl_mtd, 1, NULL);
        if (ret)
-               goto err;
+               goto err_chip;
 
        ret = flctl_chip_init_tail(flctl_mtd);
        if (ret)
-               goto err;
+               goto err_chip;
 
        ret = nand_scan_tail(flctl_mtd);
        if (ret)
-               goto err;
+               goto err_chip;
 
        mtd_device_register(flctl_mtd, pdata->parts, pdata->nr_parts);
 
        return 0;
 
-err:
+err_chip:
+       pm_runtime_disable(&pdev->dev);
+err_iomap:
        kfree(flctl);
        return ret;
 }
@@ -897,6 +929,7 @@ static int __devexit flctl_remove(struct platform_device *pdev)
        struct sh_flctl *flctl = platform_get_drvdata(pdev);
 
        nand_release(&flctl->mtd);
+       pm_runtime_disable(&pdev->dev);
        kfree(flctl);
 
        return 0;

diff --git a/include/linux/mtd/sh_flctl.h b/include/linux/mtd/sh_flctl.h
index 8bcf299..a38e1fa 100644 (file)
--- a/include/linux/mtd/sh_flctl.h
+++ b/include/linux/mtd/sh_flctl.h
@@ -23,6 +23,7 @@
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/nand.h>
 #include <linux/mtd/partitions.h>
+#include <linux/pm_qos.h>
 
 /* FLCTL registers */
 #define FLCMNCR(f)             (f->reg + 0x0)
@@ -131,6 +132,7 @@ struct sh_flctl {
        struct mtd_info         mtd;
        struct nand_chip        chip;
        struct platform_device  *pdev;
+       struct dev_pm_qos_request pm_qos;
        void __iomem            *reg;
 
        uint8_t done_buff[2048 + 64];   /* max size 2048 + 64 */
@@ -149,6 +151,7 @@ struct sh_flctl {
        unsigned page_size:1;   /* NAND page size (0 = 512, 1 = 2048) */
        unsigned hwecc:1;       /* Hardware ECC (0 = disabled, 1 = enabled) */
        unsigned holden:1;      /* Hardware has FLHOLDCR and HOLDEN is set */
+       unsigned qos_request:1; /* QoS request to prevent deep power shutdown */
 };
 
 struct sh_flctl_platform_data {