hwrng: omap3-rom - Use runtime PM instead of custom functions

Nowadays we have runtime PM, and we can use it with autosuspend_timeout
to idle things automatically. This allows us to get rid of the custom
PM implementation.

We enable clocks and init RNG in runtime_resume, and reset RNG and
disable clocks in runtime_suspend. And then omap3_rom_rng_read()
becomes very simple and we don't need the old functions for
omap3_rom_rng_idle() and omap3_rom_rng_get_random(). We can now also
get rid of pr_fmt as we're using dev_err instead.

Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: Adam Ford <aford173@gmail.com>
Cc: Pali Rohár <pali.rohar@gmail.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/char/hw_random/omap3-rom-rng.c b/drivers/char/hw_random/omap3-rom-rng.c
index 749f6ec2bde1c25ce38d5839e9406147b344ad23..dab62b1f5e48309bb683c476588d64f775dfcc08 100644 (file)
--- a/drivers/char/hw_random/omap3-rom-rng.c
+++ b/drivers/char/hw_random/omap3-rom-rng.c
@@ -11,8 +11,6 @@
  * warranty of any kind, whether express or implied.
  */
 
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/random.h>
@@ -23,73 +21,83 @@
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 
 #define RNG_RESET                      0x01
 #define RNG_GEN_PRNG_HW_INIT           0x02
 #define RNG_GEN_HW                     0x08
 
-/* param1: ptr, param2: count, param3: flag */
-static u32 (*omap3_rom_rng_call)(u32, u32, u32);
-
 struct omap_rom_rng {
        struct clk *clk;
        struct device *dev;
        struct hwrng ops;
+       u32 (*rom_rng_call)(u32 ptr, u32 count, u32 flag);
 };
 
-static struct delayed_work idle_work;
-static int rng_idle;
-static struct clk *rng_clk;
-
-static void omap3_rom_rng_idle(struct work_struct *work)
+static int omap3_rom_rng_read(struct hwrng *rng, void *data, size_t max, bool w)
 {
+       struct omap_rom_rng *ddata;
+       u32 ptr;
        int r;
 
-       r = omap3_rom_rng_call(0, 0, RNG_RESET);
-       if (r != 0) {
-               pr_err("reset failed: %d\n", r);
-               return;
+       ddata = (struct omap_rom_rng *)rng->priv;
+
+       r = pm_runtime_get_sync(ddata->dev);
+       if (r < 0) {
+               pm_runtime_put_noidle(ddata->dev);
+
+               return r;
        }
-       clk_disable_unprepare(rng_clk);
-       rng_idle = 1;
+
+       ptr = virt_to_phys(data);
+       r = ddata->rom_rng_call(ptr, 4, RNG_GEN_HW);
+       if (r != 0)
+               r = -EINVAL;
+       else
+               r = 4;
+
+       pm_runtime_mark_last_busy(ddata->dev);
+       pm_runtime_put_autosuspend(ddata->dev);
+
+       return r;
 }
 
-static int omap3_rom_rng_get_random(void *buf, unsigned int count)
+static int omap_rom_rng_runtime_suspend(struct device *dev)
 {
-       u32 r;
-       u32 ptr;
+       struct omap_rom_rng *ddata;
+       int r;
 
-       cancel_delayed_work_sync(&idle_work);
-       if (rng_idle) {
-               r = clk_prepare_enable(rng_clk);
-               if (r)
-                       return r;
-
-               r = omap3_rom_rng_call(0, 0, RNG_GEN_PRNG_HW_INIT);
-               if (r != 0) {
-                       clk_disable_unprepare(rng_clk);
-                       pr_err("HW init failed: %d\n", r);
-                       return -EIO;
-               }
-               rng_idle = 0;
-       }
+       ddata = dev_get_drvdata(dev);
 
-       ptr = virt_to_phys(buf);
-       r = omap3_rom_rng_call(ptr, count, RNG_GEN_HW);
-       schedule_delayed_work(&idle_work, msecs_to_jiffies(500));
+       r = ddata->rom_rng_call(0, 0, RNG_RESET);
        if (r != 0)
-               return -EINVAL;
+               dev_err(dev, "reset failed: %d\n", r);
+
+       clk_disable_unprepare(ddata->clk);
+
        return 0;
 }
 
-static int omap3_rom_rng_read(struct hwrng *rng, void *data, size_t max, bool w)
+static int omap_rom_rng_runtime_resume(struct device *dev)
 {
+       struct omap_rom_rng *ddata;
        int r;
 
-       r = omap3_rom_rng_get_random(data, 4);
+       ddata = dev_get_drvdata(dev);
+
+       r = clk_prepare_enable(ddata->clk);
        if (r < 0)
                return r;
-       return 4;
+
+       r = ddata->rom_rng_call(0, 0, RNG_GEN_PRNG_HW_INIT);
+       if (r != 0) {
+               clk_disable(ddata->clk);
+               dev_err(dev, "HW init failed: %d\n", r);
+
+               return -EIO;
+       }
+
+       return 0;
 }
 
 static int omap3_rom_rng_probe(struct platform_device *pdev)
@@ -113,27 +121,33 @@ static int omap3_rom_rng_probe(struct platform_device *pdev)
        }
        dev_set_drvdata(ddata->dev, ddata);
 
-       omap3_rom_rng_call = pdev->dev.platform_data;
-       if (!omap3_rom_rng_call) {
+       ddata->rom_rng_call = pdev->dev.platform_data;
+       if (!ddata->rom_rng_call) {
                dev_err(ddata->dev, "rom_rng_call is NULL\n");
                return -EINVAL;
        }
 
-       INIT_DELAYED_WORK(&idle_work, omap3_rom_rng_idle);
        ddata->clk = devm_clk_get(ddata->dev, "ick");
        if (IS_ERR(ddata->clk)) {
                dev_err(ddata->dev, "unable to get RNG clock\n");
                return PTR_ERR(ddata->clk);
        }
-       rng_clk = ddata->clk;
 
-       /* Leave the RNG in reset state. */
-       ret = clk_prepare_enable(ddata->clk);
-       if (ret)
-               return ret;
-       omap3_rom_rng_idle(0);
+       pm_runtime_enable(ddata->dev);
+
+       ret = hwrng_register(&ddata->ops);
+       if (!ret)
+               goto err_disable;
+
+       pm_runtime_set_autosuspend_delay(ddata->dev, 500);
+       pm_runtime_use_autosuspend(ddata->dev);
+
+       return 0;
 
-       return hwrng_register(&ddata->ops);
+err_disable:
+       pm_runtime_disable(ddata->dev);
+
+       return ret;
 }
 
 static int omap3_rom_rng_remove(struct platform_device *pdev)
@@ -141,10 +155,10 @@ static int omap3_rom_rng_remove(struct platform_device *pdev)
        struct omap_rom_rng *ddata;
 
        ddata = dev_get_drvdata(&pdev->dev);
-       cancel_delayed_work_sync(&idle_work);
        hwrng_unregister(&ddata->ops);
-       if (!rng_idle)
-               clk_disable_unprepare(rng_clk);
+       pm_runtime_dont_use_autosuspend(ddata->dev);
+       pm_runtime_disable(ddata->dev);
+
        return 0;
 }
 
@@ -154,10 +168,16 @@ static const struct of_device_id omap_rom_rng_match[] = {
 };
 MODULE_DEVICE_TABLE(of, omap_rom_rng_match);
 
+static const struct dev_pm_ops omap_rom_rng_pm_ops = {
+       SET_SYSTEM_SLEEP_PM_OPS(omap_rom_rng_runtime_suspend,
+                               omap_rom_rng_runtime_resume)
+};
+
 static struct platform_driver omap3_rom_rng_driver = {
        .driver = {
                .name           = "omap3-rom-rng",
                .of_match_table = omap_rom_rng_match,
+               .pm = &omap_rom_rng_pm_ops,
        },
        .probe          = omap3_rom_rng_probe,
        .remove         = omap3_rom_rng_remove,