From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6250EC00528 for ; Tue, 25 Jul 2023 20:00:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=z5cPQuAbEZXBfnVM4fsyvMt1sRstClOd/6sBIoLe73s=; b=f7iZ/51i/6JAzw aLieLVtKFnH6rnVCwuKQmenu/fJBvzBLtr3HrV+YnmH76Khox6XbrBaQ7JVqHMug+8RLUlyhvetjK orq0382OizbfCEn+D+ho1vOUl+zKre6d/olkBRrQZywFHVP3M2w/tZx0jok/AzA1iYcsqh+zoQ+IW 8nF0oW9MQUeMO7IZsHcSzb1XK7e6OusrkPdRcn/bZOd/ubfWsuH1aoeqayiZm9WqQrf6IHK49VJ0u qGtkYRFfaUMjYP6vzOjSB/3n9JKtMP9G6ah3+m74qmo0qp3h1lJkQCnqNAnQnc/Ax1EgsRg5WIwNU 1Os0CXrOXhTPZYo3S6PQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qOOBq-008NyN-17; Tue, 25 Jul 2023 19:59:26 +0000 Received: from viti.kaiser.cx ([2a01:238:43fe:e600:cd0c:bd4a:7a3:8e9f]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qOOBm-008Nwf-21; Tue, 25 Jul 2023 19:59:24 +0000 Received: from martin by viti.kaiser.cx with local (Exim 4.89) (envelope-from ) id 1qOOBR-0007K0-M1; Tue, 25 Jul 2023 21:59:01 +0200 Date: Tue, 25 Jul 2023 21:59:01 +0200 From: Martin Kaiser To: Alexey Romanov Cc: narmstrong@baylibre.com, neil.armstrong@linaro.org, olivia@selenic.com, herbert@gondor.apana.org.au, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, khilman@baylibre.com, jbrunet@baylibre.com, martin.blumenstingl@googlemail.com, f.fainelli@gmail.com, hkallweit1@gmail.com, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-crypto@vger.kernel.org, kernel@sberdevices.ru Subject: Re: [PATCH v1 1/3] drivers: rng: add check status bit feature Message-ID: <20230725195901.n2klvgz7outqaatk@viti.kaiser.cx> References: <20230725141252.98848-1-avromanov@sberdevices.ru> <20230725141252.98848-2-avromanov@sberdevices.ru> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230725141252.98848-2-avromanov@sberdevices.ru> User-Agent: NeoMutt/20170113 (1.7.2) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230725_125922_831730_00D4E15C X-CRM114-Status: GOOD ( 22.53 ) X-BeenThere: linux-amlogic@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-amlogic" Errors-To: linux-amlogic-bounces+linux-amlogic=archiver.kernel.org@lists.infradead.org Alexey Romanov (avromanov@sberdevices.ru) wrote: > For some Amlogic SOC's, mechanism to obtain random number > has been changed. For example, S4 now uses status bit waiting algo. > Signed-off-by: Alexey Romanov > --- > drivers/char/hw_random/meson-rng.c | 77 ++++++++++++++++++++++++++++-- > 1 file changed, 74 insertions(+), 3 deletions(-) > diff --git a/drivers/char/hw_random/meson-rng.c b/drivers/char/hw_random/meson-rng.c > index a4eb8e35f13d..c6d7349630a1 100644 > --- a/drivers/char/hw_random/meson-rng.c > +++ b/drivers/char/hw_random/meson-rng.c > @@ -14,19 +14,65 @@ > #include > #include > -#define RNG_DATA 0x00 > +struct meson_rng_priv { > + bool check_status_bit; > + unsigned int data_offset; > + unsigned int cfg_offset; > +}; > struct meson_rng_data { > void __iomem *base; > struct hwrng rng; > + struct device *dev; > + const struct meson_rng_priv *priv; > }; > +#define RUN_BIT 0 > +#define SEED_READY_STS_BIT 31 > +#define RETRY_CNT 100 > + > +static int meson_rng_wait_status(void __iomem *cfg_addr, int bit) > +{ > + u32 status; > + u32 cnt = 0; > + > + do { > + status = readl_relaxed(cfg_addr) & BIT(bit); > + cpu_relax(); > + } while (status && (cnt++ < RETRY_CNT)); > + Could you use readl_relaxed_poll_timeout here instead of open coding the loop? > + if (status) > + return -EBUSY; > + > + return 0; > +} > + > static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) > { > struct meson_rng_data *data = > container_of(rng, struct meson_rng_data, rng); > + const struct meson_rng_priv *priv = data->priv; > + > + if (priv->check_status_bit) { > + void __iomem *cfg_addr = data->base + priv->cfg_offset; > + int err; > + > + writel_relaxed(readl_relaxed(cfg_addr) | BIT(SEED_READY_STS_BIT), cfg_addr); > - *(u32 *)buf = readl_relaxed(data->base + RNG_DATA); > + err = meson_rng_wait_status(cfg_addr, SEED_READY_STS_BIT); > + if (err) { > + dev_err(data->dev, "Seed isn't ready, try again\n"); > + return err; > + } > + > + err = meson_rng_wait_status(cfg_addr, RUN_BIT); > + if (err) { > + dev_err(data->dev, "Can't get random number, try again\n"); > + return err; > + } > + } > + > + *(u32 *)buf = readl_relaxed(data->base + priv->data_offset); > return sizeof(u32); > } > @@ -41,6 +87,10 @@ static int meson_rng_probe(struct platform_device *pdev) > if (!data) > return -ENOMEM; > + data->priv = device_get_match_data(&pdev->dev); > + if (!data->priv) > + return -ENODEV; > + > data->base = devm_platform_ioremap_resource(pdev, 0); > if (IS_ERR(data->base)) > return PTR_ERR(data->base); > @@ -53,11 +103,32 @@ static int meson_rng_probe(struct platform_device *pdev) > data->rng.name = pdev->name; > data->rng.read = meson_rng_read; > + data->dev = &pdev->dev; > + > return devm_hwrng_register(dev, &data->rng); > } > +static const struct meson_rng_priv meson_rng_priv = { > + .check_status_bit = false, > + .data_offset = 0x0, > + .cfg_offset = 0x0, > +}; > + > +static const struct meson_rng_priv meson_rng_priv_s4 = { > + .check_status_bit = true, > + .data_offset = 0x8, > + .cfg_offset = 0x0, > +}; > + > static const struct of_device_id meson_rng_of_match[] = { > - { .compatible = "amlogic,meson-rng", }, > + { > + .compatible = "amlogic,meson-rng", > + .data = (void *)&meson_rng_priv, > + }, > + { > + .compatible = "amlogic,meson-rng-s4", > + .data = (void *)&meson_rng_priv_s4, > + }, > {}, > }; > MODULE_DEVICE_TABLE(of, meson_rng_of_match); > -- > 2.38.1 _______________________________________________ linux-amlogic mailing list linux-amlogic@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-amlogic