![Stefan Wahren](/assets/img/avatar_default.png)
In case the probe of the clock is deferred, we would assume it is
optional. This is wrong, so defer the probe of this driver until
the clock is available.
Fixes: 791af4f490
("hwrng: bcm2835 - Manage an optional clock")
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
215 lines
5.2 KiB
C
215 lines
5.2 KiB
C
/**
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* Copyright (c) 2010-2012 Broadcom. All rights reserved.
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* Copyright (c) 2013 Lubomir Rintel
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License ("GPL")
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* version 2, as published by the Free Software Foundation.
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*/
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#include <linux/hw_random.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of_address.h>
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#include <linux/of_platform.h>
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#include <linux/platform_device.h>
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#include <linux/printk.h>
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#include <linux/clk.h>
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#define RNG_CTRL 0x0
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#define RNG_STATUS 0x4
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#define RNG_DATA 0x8
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#define RNG_INT_MASK 0x10
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/* enable rng */
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#define RNG_RBGEN 0x1
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/* the initial numbers generated are "less random" so will be discarded */
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#define RNG_WARMUP_COUNT 0x40000
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#define RNG_INT_OFF 0x1
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struct bcm2835_rng_priv {
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struct hwrng rng;
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void __iomem *base;
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bool mask_interrupts;
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struct clk *clk;
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};
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static inline struct bcm2835_rng_priv *to_rng_priv(struct hwrng *rng)
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{
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return container_of(rng, struct bcm2835_rng_priv, rng);
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}
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static inline u32 rng_readl(struct bcm2835_rng_priv *priv, u32 offset)
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{
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/* MIPS chips strapped for BE will automagically configure the
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* peripheral registers for CPU-native byte order.
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*/
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if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
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return __raw_readl(priv->base + offset);
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else
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return readl(priv->base + offset);
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}
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static inline void rng_writel(struct bcm2835_rng_priv *priv, u32 val,
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u32 offset)
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{
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if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
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__raw_writel(val, priv->base + offset);
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else
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writel(val, priv->base + offset);
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}
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static int bcm2835_rng_read(struct hwrng *rng, void *buf, size_t max,
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bool wait)
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{
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struct bcm2835_rng_priv *priv = to_rng_priv(rng);
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u32 max_words = max / sizeof(u32);
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u32 num_words, count;
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while ((rng_readl(priv, RNG_STATUS) >> 24) == 0) {
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if (!wait)
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return 0;
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cpu_relax();
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}
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num_words = rng_readl(priv, RNG_STATUS) >> 24;
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if (num_words > max_words)
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num_words = max_words;
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for (count = 0; count < num_words; count++)
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((u32 *)buf)[count] = rng_readl(priv, RNG_DATA);
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return num_words * sizeof(u32);
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}
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static int bcm2835_rng_init(struct hwrng *rng)
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{
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struct bcm2835_rng_priv *priv = to_rng_priv(rng);
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int ret = 0;
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u32 val;
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if (!IS_ERR(priv->clk)) {
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ret = clk_prepare_enable(priv->clk);
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if (ret)
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return ret;
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}
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if (priv->mask_interrupts) {
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/* mask the interrupt */
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val = rng_readl(priv, RNG_INT_MASK);
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val |= RNG_INT_OFF;
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rng_writel(priv, val, RNG_INT_MASK);
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}
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/* set warm-up count & enable */
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rng_writel(priv, RNG_WARMUP_COUNT, RNG_STATUS);
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rng_writel(priv, RNG_RBGEN, RNG_CTRL);
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return ret;
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}
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static void bcm2835_rng_cleanup(struct hwrng *rng)
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{
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struct bcm2835_rng_priv *priv = to_rng_priv(rng);
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/* disable rng hardware */
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rng_writel(priv, 0, RNG_CTRL);
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if (!IS_ERR(priv->clk))
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clk_disable_unprepare(priv->clk);
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}
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struct bcm2835_rng_of_data {
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bool mask_interrupts;
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};
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static const struct bcm2835_rng_of_data nsp_rng_of_data = {
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.mask_interrupts = true,
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};
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static const struct of_device_id bcm2835_rng_of_match[] = {
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{ .compatible = "brcm,bcm2835-rng"},
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{ .compatible = "brcm,bcm-nsp-rng", .data = &nsp_rng_of_data },
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{ .compatible = "brcm,bcm5301x-rng", .data = &nsp_rng_of_data },
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{ .compatible = "brcm,bcm6368-rng"},
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{},
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};
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static int bcm2835_rng_probe(struct platform_device *pdev)
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{
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const struct bcm2835_rng_of_data *of_data;
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struct device *dev = &pdev->dev;
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struct device_node *np = dev->of_node;
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const struct of_device_id *rng_id;
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struct bcm2835_rng_priv *priv;
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struct resource *r;
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int err;
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priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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platform_set_drvdata(pdev, priv);
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r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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/* map peripheral */
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priv->base = devm_ioremap_resource(dev, r);
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if (IS_ERR(priv->base))
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return PTR_ERR(priv->base);
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/* Clock is optional on most platforms */
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priv->clk = devm_clk_get(dev, NULL);
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if (IS_ERR(priv->clk) && PTR_ERR(priv->clk) == -EPROBE_DEFER)
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return -EPROBE_DEFER;
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priv->rng.name = pdev->name;
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priv->rng.init = bcm2835_rng_init;
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priv->rng.read = bcm2835_rng_read;
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priv->rng.cleanup = bcm2835_rng_cleanup;
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rng_id = of_match_node(bcm2835_rng_of_match, np);
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if (!rng_id)
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return -EINVAL;
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/* Check for rng init function, execute it */
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of_data = rng_id->data;
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if (of_data)
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priv->mask_interrupts = of_data->mask_interrupts;
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/* register driver */
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err = devm_hwrng_register(dev, &priv->rng);
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if (err)
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dev_err(dev, "hwrng registration failed\n");
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else
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dev_info(dev, "hwrng registered\n");
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return err;
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}
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MODULE_DEVICE_TABLE(of, bcm2835_rng_of_match);
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static struct platform_device_id bcm2835_rng_devtype[] = {
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{ .name = "bcm2835-rng" },
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{ .name = "bcm63xx-rng" },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(platform, bcm2835_rng_devtype);
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static struct platform_driver bcm2835_rng_driver = {
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.driver = {
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.name = "bcm2835-rng",
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.of_match_table = bcm2835_rng_of_match,
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},
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.probe = bcm2835_rng_probe,
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.id_table = bcm2835_rng_devtype,
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};
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module_platform_driver(bcm2835_rng_driver);
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MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
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MODULE_DESCRIPTION("BCM2835 Random Number Generator (RNG) driver");
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MODULE_LICENSE("GPL v2");
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