[PATCH 2/2] hwrng: msm: add ACPI support

Vinod
2018-06-22T04:23:22Z

On 21-06-18, 10:17, Timur Tabi wrote:
> Add support for probing on ACPI systems, with ACPI HID QCOM8160.
>
> On ACPI systems, clocks are always enabled, the PRNG should
> already be enabled, and the register region is read-only.
> The driver only verifies that the hardware is already
> enabled never tries to disable or configure it.

so if you are using v2 hardware, are you pointing to High Level OS EE or
some other..?

> Signed-off-by: Timur Tabi <timur@codeaurora.org>
> ---
> drivers/char/hw_random/msm-rng.c | 40 ++++++++++++++++++++++++++++++++++------
> 1 file changed, 34 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/char/hw_random/msm-rng.c b/drivers/char/hw_random/msm-rng.c
> index 44580588b938..f34713d23d77 100644
> --- a/drivers/char/hw_random/msm-rng.c
> +++ b/drivers/char/hw_random/msm-rng.c
> @@ -20,6 +20,7 @@
> #include <linux/of.h>
> #include <linux/platform_device.h>
> #include <linux/spinlock.h>
> +#include <linux/acpi.h>
>
> /* Device specific register offsets */
> #define PRNG_DATA_OUT 0x0000
> @@ -186,16 +187,32 @@ static int msm_rng_probe(struct platform_device *pdev)
> if (IS_ERR(rng->base))
> return PTR_ERR(rng->base);
>
> - rng->clk = devm_clk_get(&pdev->dev, "core");
> - if (IS_ERR(rng->clk))
> - return PTR_ERR(rng->clk);
> -
> rng->hwrng.name = KBUILD_MODNAME;
> - rng->hwrng.init = msm_rng_init;
> - rng->hwrng.cleanup = msm_rng_cleanup;
> rng->hwrng.read = msm_rng_read;
> spin_lock_init(&rng->lock);
>
> + /*
> + * ACPI systems have v2 hardware. The clocks are always enabled,
> + * the PRNG register space is read-only, and the PRNG should
> + * already be enabled.
> + */
> + if (has_acpi_companion(&pdev->dev)) {
> + u32 val;
> +
> + val = readl(rng->base + PRNG_CONFIG);

v2 EEs dont seem to have CONFIG register, so not sure about this one

> + if (!(val & PRNG_CONFIG_HW_ENABLE)) {
> + dev_err(&pdev->dev, "device is not enabled\n");
> + return -ENODEV;
> + }
> + } else {
> + rng->clk = devm_clk_get(&pdev->dev, "core");
> + if (IS_ERR(rng->clk))
> + return PTR_ERR(rng->clk);
> +
> + rng->hwrng.init = msm_rng_init;
> + rng->hwrng.cleanup = msm_rng_cleanup;
> + }
> +
> ret = devm_hwrng_register(&pdev->dev, &rng->hwrng);
> if (ret) {
> dev_err(&pdev->dev, "failed to register hwrng\n");
> @@ -211,11 +228,22 @@ static int msm_rng_probe(struct platform_device *pdev)
> };
> MODULE_DEVICE_TABLE(of, msm_rng_of_match);
>
> +#if IS_ENABLED(CONFIG_ACPI)
> +static const struct acpi_device_id msm_rng_acpi_match[] = {
> + {
> + .id = "QCOM8160", /* v2 PRNG */
> + },
> + {}
> +};
> +MODULE_DEVICE_TABLE(acpi, msm_rng_acpi_match);
> +#endif
> +
> static struct platform_driver msm_rng_driver = {
> .probe = msm_rng_probe,
> .driver = {
> .name = KBUILD_MODNAME,
> .of_match_table = of_match_ptr(msm_rng_of_match),
> + .acpi_match_table = ACPI_PTR(msm_rng_acpi_match),
> }
> };
> module_platform_driver(msm_rng_driver);
> --
> Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
> Technologies, Inc. Qualcomm Technologies, Inc. is a member of the
> Code Aurora Forum, a Linux Foundation Collaborative Project.

--
~Vinod