On 10/03/13 07:52, Stanimir Varbanov wrote:
> +#define PRNG_CONFIG_MASK 0x00000002
> +#define PRNG_CONFIG_HW_ENABLE BIT(1)
These two are the same so please drop the PRNG_CONFIG_MASK define and
just use the PRNG_CONFIG_HW_ENABLE define.
> +#define PRNG_STATUS_DATA_AVAIL BIT(0)
> +
> +#define MAX_HW_FIFO_DEPTH 16
> +#define MAX_HW_FIFO_SIZE (MAX_HW_FIFO_DEPTH * 4)
> +#define WORD_SZ 4
> +
> +struct msm_rng {
> + void __iomem *base;
> + struct clk *clk;
> +};
> +
> +static int msm_rng_enable(struct msm_rng *rng, int enable)
> +{
> + u32 val;
> + int ret;
> +
> + ret = clk_prepare_enable(rng->clk);
> + if (ret)
> + return ret;
> +
> + if (enable) {
> + /* Enable PRNG only if it is not already enabled */
> + val = readl_relaxed(rng->base + PRNG_CONFIG);
> + if (val & PRNG_CONFIG_HW_ENABLE)
> + goto already_enabled;
> +
> + /* PRNG is not enabled */
> + val = readl_relaxed(rng->base + PRNG_LFSR_CFG);
> + val &= ~PRNG_LFSR_CFG_MASK;
> + val |= PRNG_LFSR_CFG_CLOCKS;
> + writel(val, rng->base + PRNG_LFSR_CFG);
> +
> + val = readl_relaxed(rng->base + PRNG_CONFIG);
> + val &= ~PRNG_CONFIG_MASK;
> + val |= PRNG_CONFIG_HW_ENABLE;
> + writel(val, rng->base + PRNG_CONFIG);
This could just be
val = readl_relaxed(rng->base + PRNG_CONFIG);
val |= PRNG_CONFIG_HW_ENABLE;
writel(val, rng->base + PRNG_CONFIG);
> + } else {
> + val = readl_relaxed(rng->base + PRNG_CONFIG);
> + val &= ~PRNG_CONFIG_MASK;
> + writel(val, rng->base + PRNG_CONFIG);
> + }
> +
> +already_enabled:
> + clk_disable_unprepare(rng->clk);
> + return 0;
> +}
> +
[...]
> +static int msm_rng_probe(struct platform_device *pdev)
> +{
> + struct msm_rng *rng;
> + struct device_node *np;
> + struct resource res;
> + int ret;
> +
> + np = of_node_get(pdev->dev.of_node);
> + if (!np)
> + return -ENODEV;
This is unnecessary.
> +
> + rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
> + if (!rng) {
> + ret = -ENOMEM;
> + goto err_exit;
> + }
> +
> + ret = of_address_to_resource(np, 0, &res);
> + if (ret)
> + goto err_exit;
We should just do
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
rng->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(rng->base))
return PTR_ERR(rng->base);
> +
> + rng->base = devm_ioremap_resource(&pdev->dev, &res);
> + if (IS_ERR(rng->base)) {
> + ret = PTR_ERR(rng->base);
> + goto err_exit;
> + }
> +
> + rng->clk = devm_clk_get(&pdev->dev, "prng");
> + if (IS_ERR(rng->clk)) {
> + ret = PTR_ERR(rng->clk);
> + goto err_exit;
> + }
> +
> + msm_rng_ops.priv = (unsigned long) rng;
> + ret = hwrng_register(&msm_rng_ops);
> + if (ret)
> + dev_err(&pdev->dev, "failed to register hwrng\n");
> +
> +err_exit:
Doing all that should make this goto exit path unnecessary.
> + of_node_put(np);
> + return ret;
> +}
> +
> +static int msm_rng_remove(struct platform_device *pdev)
> +{
> + hwrng_unregister(&msm_rng_ops);
> + return 0;
> +}
> +
> +static struct of_device_id msm_rng_of_match[] = {
const?
> + { .compatible = "qcom,prng", },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, msm_rng_of_match);
> +
> +static struct platform_driver msm_rng_driver = {
> + .probe = msm_rng_probe,
> + .remove = msm_rng_remove,
> + .driver = {
> + .name = KBUILD_MODNAME,
> + .owner = THIS_MODULE,
> + .of_match_table = of_match_ptr(msm_rng_of_match),
> + }
> +};
> +module_platform_driver(msm_rng_driver);
> +
> +MODULE_AUTHOR("The Linux Foundation");
> +MODULE_DESCRIPTION("Qualcomm MSM random number generator driver");
> +MODULE_LICENSE("GPL v2");
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