From: Vinod Subject: Re: [PATCH 2/2] hwrng: msm: add ACPI support Date: Fri, 22 Jun 2018 09:53:22 +0530 Message-ID: <20180622042322.GF27187@vkoul-mobl> References: <1529594276-12210-1-git-send-email-timur@codeaurora.org> <1529594276-12210-2-git-send-email-timur@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: timur@kernel.org, linux-arm-msm@vger.kernel.org, swboyd@chromium.org, linux-crypto@vger.kernel.org, Matt Mackall , linux-arm-kernel@lists.infradead.org To: Timur Tabi Return-path: Content-Disposition: inline In-Reply-To: <1529594276-12210-2-git-send-email-timur@codeaurora.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org List-Id: linux-crypto.vger.kernel.org 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 > --- > 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 > #include > #include > +#include > > /* 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