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129 lines
3.0 KiB
129 lines
3.0 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Generic PowerPC 44x RNG driver |
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* |
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* Copyright 2011 IBM Corporation |
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*/ |
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#include <linux/module.h> |
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#include <linux/kernel.h> |
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#include <linux/interrupt.h> |
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#include <linux/platform_device.h> |
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#include <linux/hw_random.h> |
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#include <linux/delay.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/io.h> |
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#include "crypto4xx_core.h" |
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#include "crypto4xx_trng.h" |
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#include "crypto4xx_reg_def.h" |
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#define PPC4XX_TRNG_CTRL 0x0008 |
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#define PPC4XX_TRNG_CTRL_DALM 0x20 |
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#define PPC4XX_TRNG_STAT 0x0004 |
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#define PPC4XX_TRNG_STAT_B 0x1 |
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#define PPC4XX_TRNG_DATA 0x0000 |
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static int ppc4xx_trng_data_present(struct hwrng *rng, int wait) |
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{ |
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struct crypto4xx_device *dev = (void *)rng->priv; |
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int busy, i, present = 0; |
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for (i = 0; i < 20; i++) { |
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busy = (in_le32(dev->trng_base + PPC4XX_TRNG_STAT) & |
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PPC4XX_TRNG_STAT_B); |
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if (!busy || !wait) { |
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present = 1; |
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break; |
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} |
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udelay(10); |
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} |
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return present; |
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} |
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static int ppc4xx_trng_data_read(struct hwrng *rng, u32 *data) |
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{ |
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struct crypto4xx_device *dev = (void *)rng->priv; |
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*data = in_le32(dev->trng_base + PPC4XX_TRNG_DATA); |
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return 4; |
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} |
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static void ppc4xx_trng_enable(struct crypto4xx_device *dev, bool enable) |
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{ |
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u32 device_ctrl; |
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device_ctrl = readl(dev->ce_base + CRYPTO4XX_DEVICE_CTRL); |
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if (enable) |
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device_ctrl |= PPC4XX_TRNG_EN; |
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else |
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device_ctrl &= ~PPC4XX_TRNG_EN; |
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writel(device_ctrl, dev->ce_base + CRYPTO4XX_DEVICE_CTRL); |
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} |
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static const struct of_device_id ppc4xx_trng_match[] = { |
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{ .compatible = "ppc4xx-rng", }, |
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{ .compatible = "amcc,ppc460ex-rng", }, |
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{ .compatible = "amcc,ppc440epx-rng", }, |
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{}, |
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}; |
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void ppc4xx_trng_probe(struct crypto4xx_core_device *core_dev) |
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{ |
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struct crypto4xx_device *dev = core_dev->dev; |
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struct device_node *trng = NULL; |
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struct hwrng *rng = NULL; |
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int err; |
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/* Find the TRNG device node and map it */ |
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trng = of_find_matching_node(NULL, ppc4xx_trng_match); |
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if (!trng || !of_device_is_available(trng)) { |
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of_node_put(trng); |
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return; |
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} |
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dev->trng_base = of_iomap(trng, 0); |
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of_node_put(trng); |
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if (!dev->trng_base) |
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goto err_out; |
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rng = kzalloc(sizeof(*rng), GFP_KERNEL); |
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if (!rng) |
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goto err_out; |
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rng->name = KBUILD_MODNAME; |
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rng->data_present = ppc4xx_trng_data_present; |
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rng->data_read = ppc4xx_trng_data_read; |
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rng->priv = (unsigned long) dev; |
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core_dev->trng = rng; |
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ppc4xx_trng_enable(dev, true); |
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out_le32(dev->trng_base + PPC4XX_TRNG_CTRL, PPC4XX_TRNG_CTRL_DALM); |
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err = devm_hwrng_register(core_dev->device, core_dev->trng); |
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if (err) { |
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ppc4xx_trng_enable(dev, false); |
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dev_err(core_dev->device, "failed to register hwrng (%d).\n", |
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err); |
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goto err_out; |
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} |
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return; |
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err_out: |
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iounmap(dev->trng_base); |
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kfree(rng); |
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dev->trng_base = NULL; |
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core_dev->trng = NULL; |
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} |
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void ppc4xx_trng_remove(struct crypto4xx_core_device *core_dev) |
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{ |
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if (core_dev && core_dev->trng) { |
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struct crypto4xx_device *dev = core_dev->dev; |
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devm_hwrng_unregister(core_dev->device, core_dev->trng); |
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ppc4xx_trng_enable(dev, false); |
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iounmap(dev->trng_base); |
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kfree(core_dev->trng); |
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} |
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} |
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MODULE_ALIAS("ppc4xx_rng");
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