diff options
Diffstat (limited to 'drivers/char/hw_random/atmel-rng.c')
| -rw-r--r-- | drivers/char/hw_random/atmel-rng.c | 148 |
1 files changed, 91 insertions, 57 deletions
diff --git a/drivers/char/hw_random/atmel-rng.c b/drivers/char/hw_random/atmel-rng.c index ecb71c4317a5..b8effe77d80f 100644 --- a/drivers/char/hw_random/atmel-rng.c +++ b/drivers/char/hw_random/atmel-rng.c @@ -13,13 +13,16 @@ #include <linux/err.h> #include <linux/clk.h> #include <linux/io.h> +#include <linux/iopoll.h> #include <linux/hw_random.h> #include <linux/of_device.h> #include <linux/platform_device.h> +#include <linux/pm_runtime.h> #define TRNG_CR 0x00 #define TRNG_MR 0x04 #define TRNG_ISR 0x1c +#define TRNG_ISR_DATRDY BIT(0) #define TRNG_ODATA 0x50 #define TRNG_KEY 0x524e4700 /* RNG */ @@ -34,37 +37,79 @@ struct atmel_trng { struct clk *clk; void __iomem *base; struct hwrng rng; + bool has_half_rate; }; +static bool atmel_trng_wait_ready(struct atmel_trng *trng, bool wait) +{ + int ready; + + ready = readl(trng->base + TRNG_ISR) & TRNG_ISR_DATRDY; + if (!ready && wait) + readl_poll_timeout(trng->base + TRNG_ISR, ready, + ready & TRNG_ISR_DATRDY, 1000, 20000); + + return !!ready; +} + static int atmel_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait) { struct atmel_trng *trng = container_of(rng, struct atmel_trng, rng); u32 *data = buf; + int ret; - /* data ready? */ - if (readl(trng->base + TRNG_ISR) & 1) { - *data = readl(trng->base + TRNG_ODATA); - /* - ensure data ready is only set again AFTER the next data - word is ready in case it got set between checking ISR - and reading ODATA, so we don't risk re-reading the - same word - */ - readl(trng->base + TRNG_ISR); - return 4; - } else - return 0; + ret = pm_runtime_get_sync((struct device *)trng->rng.priv); + if (ret < 0) { + pm_runtime_put_sync((struct device *)trng->rng.priv); + return ret; + } + + ret = atmel_trng_wait_ready(trng, wait); + if (!ret) + goto out; + + *data = readl(trng->base + TRNG_ODATA); + /* + * ensure data ready is only set again AFTER the next data word is ready + * in case it got set between checking ISR and reading ODATA, so we + * don't risk re-reading the same word + */ + readl(trng->base + TRNG_ISR); + ret = 4; + +out: + pm_runtime_mark_last_busy((struct device *)trng->rng.priv); + pm_runtime_put_sync_autosuspend((struct device *)trng->rng.priv); + return ret; } -static void atmel_trng_enable(struct atmel_trng *trng) +static int atmel_trng_init(struct atmel_trng *trng) { + unsigned long rate; + int ret; + + ret = clk_prepare_enable(trng->clk); + if (ret) + return ret; + + if (trng->has_half_rate) { + rate = clk_get_rate(trng->clk); + + /* if peripheral clk is above 100MHz, set HALFR */ + if (rate > 100000000) + writel(TRNG_HALFR, trng->base + TRNG_MR); + } + writel(TRNG_KEY | 1, trng->base + TRNG_CR); + + return 0; } -static void atmel_trng_disable(struct atmel_trng *trng) +static void atmel_trng_cleanup(struct atmel_trng *trng) { writel(TRNG_KEY, trng->base + TRNG_CR); + clk_disable_unprepare(trng->clk); } static int atmel_trng_probe(struct platform_device *pdev) @@ -88,32 +133,31 @@ static int atmel_trng_probe(struct platform_device *pdev) if (!data) return -ENODEV; - if (data->has_half_rate) { - unsigned long rate = clk_get_rate(trng->clk); - - /* if peripheral clk is above 100MHz, set HALFR */ - if (rate > 100000000) - writel(TRNG_HALFR, trng->base + TRNG_MR); - } - - ret = clk_prepare_enable(trng->clk); - if (ret) - return ret; - - atmel_trng_enable(trng); + trng->has_half_rate = data->has_half_rate; trng->rng.name = pdev->name; trng->rng.read = atmel_trng_read; + trng->rng.priv = (unsigned long)&pdev->dev; + platform_set_drvdata(pdev, trng); - ret = devm_hwrng_register(&pdev->dev, &trng->rng); +#ifndef CONFIG_PM + ret = atmel_trng_init(trng); if (ret) - goto err_register; + return ret; +#endif - platform_set_drvdata(pdev, trng); + pm_runtime_set_autosuspend_delay(&pdev->dev, 100); + pm_runtime_use_autosuspend(&pdev->dev); + pm_runtime_enable(&pdev->dev); - return 0; + ret = devm_hwrng_register(&pdev->dev, &trng->rng); + if (ret) { + pm_runtime_disable(&pdev->dev); + pm_runtime_set_suspended(&pdev->dev); +#ifndef CONFIG_PM + atmel_trng_cleanup(trng); +#endif + } -err_register: - clk_disable_unprepare(trng->clk); return ret; } @@ -121,43 +165,35 @@ static int atmel_trng_remove(struct platform_device *pdev) { struct atmel_trng *trng = platform_get_drvdata(pdev); - - atmel_trng_disable(trng); - clk_disable_unprepare(trng->clk); + atmel_trng_cleanup(trng); + pm_runtime_disable(&pdev->dev); + pm_runtime_set_suspended(&pdev->dev); return 0; } -#ifdef CONFIG_PM -static int atmel_trng_suspend(struct device *dev) +static int __maybe_unused atmel_trng_runtime_suspend(struct device *dev) { struct atmel_trng *trng = dev_get_drvdata(dev); - atmel_trng_disable(trng); - clk_disable_unprepare(trng->clk); + atmel_trng_cleanup(trng); return 0; } -static int atmel_trng_resume(struct device *dev) +static int __maybe_unused atmel_trng_runtime_resume(struct device *dev) { struct atmel_trng *trng = dev_get_drvdata(dev); - int ret; - ret = clk_prepare_enable(trng->clk); - if (ret) - return ret; - - atmel_trng_enable(trng); - - return 0; + return atmel_trng_init(trng); } -static const struct dev_pm_ops atmel_trng_pm_ops = { - .suspend = atmel_trng_suspend, - .resume = atmel_trng_resume, +static const struct dev_pm_ops __maybe_unused atmel_trng_pm_ops = { + SET_RUNTIME_PM_OPS(atmel_trng_runtime_suspend, + atmel_trng_runtime_resume, NULL) + SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, + pm_runtime_force_resume) }; -#endif /* CONFIG_PM */ static const struct atmel_trng_data at91sam9g45_config = { .has_half_rate = false, @@ -185,9 +221,7 @@ static struct platform_driver atmel_trng_driver = { .remove = atmel_trng_remove, .driver = { .name = "atmel-trng", -#ifdef CONFIG_PM - .pm = &atmel_trng_pm_ops, -#endif /* CONFIG_PM */ + .pm = pm_ptr(&atmel_trng_pm_ops), .of_match_table = atmel_trng_dt_ids, }, }; |