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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>
This commit is contained in:
Tony Lindgren 2019-09-14 14:02:59 -07:00 committed by Herbert Xu
parent b8d665aed4
commit 8d9d4bdc49
1 changed files with 85 additions and 65 deletions
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150
drivers/char/hw_random/omap3-rom-rng.c
View File

@ -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)
{
int r;
r = omap3_rom_rng_call(0, 0, RNG_RESET);
if (r != 0) {
pr_err("reset failed: %d\n", r);
return;
}
clk_disable_unprepare(rng_clk);
rng_idle = 1;
}
static int omap3_rom_rng_get_random(void *buf, unsigned int count)
{
u32 r;
u32 ptr;
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;
}
ptr = virt_to_phys(buf);
r = omap3_rom_rng_call(ptr, count, RNG_GEN_HW);
schedule_delayed_work(&idle_work, msecs_to_jiffies(500));
if (r != 0)
return -EINVAL;
return 0;
}
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_get_random(data, 4);
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;
}
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 omap_rom_rng_runtime_suspend(struct device *dev)
{
struct omap_rom_rng *ddata;
int r;
ddata = dev_get_drvdata(dev);
r = ddata->rom_rng_call(0, 0, RNG_RESET);
if (r != 0)
dev_err(dev, "reset failed: %d\n", r);
clk_disable_unprepare(ddata->clk);
return 0;
}
static int omap_rom_rng_runtime_resume(struct device *dev)
{
struct omap_rom_rng *ddata;
int r;
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);
return hwrng_register(&ddata->ops);
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;
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,