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209 lines
5.2 KiB
209 lines
5.2 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* RNG driver for Freescale RNGA |
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* |
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* Copyright 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved. |
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* Author: Alan Carvalho de Assis <[email protected]> |
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*/ |
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/* |
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* |
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* This driver is based on other RNG drivers. |
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*/ |
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#include <linux/clk.h> |
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#include <linux/delay.h> |
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#include <linux/hw_random.h> |
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#include <linux/io.h> |
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#include <linux/module.h> |
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#include <linux/of.h> |
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#include <linux/platform_device.h> |
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/* RNGA Registers */ |
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#define RNGA_CONTROL 0x00 |
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#define RNGA_STATUS 0x04 |
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#define RNGA_ENTROPY 0x08 |
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#define RNGA_OUTPUT_FIFO 0x0c |
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#define RNGA_MODE 0x10 |
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#define RNGA_VERIFICATION_CONTROL 0x14 |
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#define RNGA_OSC_CONTROL_COUNTER 0x18 |
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#define RNGA_OSC1_COUNTER 0x1c |
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#define RNGA_OSC2_COUNTER 0x20 |
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#define RNGA_OSC_COUNTER_STATUS 0x24 |
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/* RNGA Registers Range */ |
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#define RNG_ADDR_RANGE 0x28 |
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/* RNGA Control Register */ |
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#define RNGA_CONTROL_SLEEP 0x00000010 |
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#define RNGA_CONTROL_CLEAR_INT 0x00000008 |
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#define RNGA_CONTROL_MASK_INTS 0x00000004 |
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#define RNGA_CONTROL_HIGH_ASSURANCE 0x00000002 |
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#define RNGA_CONTROL_GO 0x00000001 |
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#define RNGA_STATUS_LEVEL_MASK 0x0000ff00 |
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/* RNGA Status Register */ |
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#define RNGA_STATUS_OSC_DEAD 0x80000000 |
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#define RNGA_STATUS_SLEEP 0x00000010 |
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#define RNGA_STATUS_ERROR_INT 0x00000008 |
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#define RNGA_STATUS_FIFO_UNDERFLOW 0x00000004 |
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#define RNGA_STATUS_LAST_READ_STATUS 0x00000002 |
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#define RNGA_STATUS_SECURITY_VIOLATION 0x00000001 |
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struct mxc_rng { |
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struct device *dev; |
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struct hwrng rng; |
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void __iomem *mem; |
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struct clk *clk; |
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}; |
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static int mxc_rnga_data_present(struct hwrng *rng, int wait) |
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{ |
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int i; |
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struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng); |
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for (i = 0; i < 20; i++) { |
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/* how many random numbers are in FIFO? [0-16] */ |
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int level = (__raw_readl(mxc_rng->mem + RNGA_STATUS) & |
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RNGA_STATUS_LEVEL_MASK) >> 8; |
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if (level || !wait) |
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return !!level; |
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udelay(10); |
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} |
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return 0; |
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} |
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static int mxc_rnga_data_read(struct hwrng *rng, u32 * data) |
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{ |
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int err; |
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u32 ctrl; |
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struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng); |
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/* retrieve a random number from FIFO */ |
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*data = __raw_readl(mxc_rng->mem + RNGA_OUTPUT_FIFO); |
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/* some error while reading this random number? */ |
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err = __raw_readl(mxc_rng->mem + RNGA_STATUS) & RNGA_STATUS_ERROR_INT; |
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/* if error: clear error interrupt, but doesn't return random number */ |
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if (err) { |
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dev_dbg(mxc_rng->dev, "Error while reading random number!\n"); |
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ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL); |
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__raw_writel(ctrl | RNGA_CONTROL_CLEAR_INT, |
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mxc_rng->mem + RNGA_CONTROL); |
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return 0; |
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} else |
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return 4; |
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} |
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static int mxc_rnga_init(struct hwrng *rng) |
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{ |
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u32 ctrl, osc; |
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struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng); |
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/* wake up */ |
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ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL); |
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__raw_writel(ctrl & ~RNGA_CONTROL_SLEEP, mxc_rng->mem + RNGA_CONTROL); |
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/* verify if oscillator is working */ |
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osc = __raw_readl(mxc_rng->mem + RNGA_STATUS); |
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if (osc & RNGA_STATUS_OSC_DEAD) { |
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dev_err(mxc_rng->dev, "RNGA Oscillator is dead!\n"); |
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return -ENODEV; |
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} |
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/* go running */ |
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ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL); |
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__raw_writel(ctrl | RNGA_CONTROL_GO, mxc_rng->mem + RNGA_CONTROL); |
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return 0; |
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} |
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static void mxc_rnga_cleanup(struct hwrng *rng) |
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{ |
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u32 ctrl; |
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struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng); |
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ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL); |
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/* stop rnga */ |
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__raw_writel(ctrl & ~RNGA_CONTROL_GO, mxc_rng->mem + RNGA_CONTROL); |
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} |
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static int __init mxc_rnga_probe(struct platform_device *pdev) |
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{ |
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int err; |
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struct mxc_rng *mxc_rng; |
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mxc_rng = devm_kzalloc(&pdev->dev, sizeof(*mxc_rng), GFP_KERNEL); |
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if (!mxc_rng) |
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return -ENOMEM; |
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mxc_rng->dev = &pdev->dev; |
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mxc_rng->rng.name = "mxc-rnga"; |
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mxc_rng->rng.init = mxc_rnga_init; |
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mxc_rng->rng.cleanup = mxc_rnga_cleanup; |
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mxc_rng->rng.data_present = mxc_rnga_data_present; |
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mxc_rng->rng.data_read = mxc_rnga_data_read; |
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mxc_rng->clk = devm_clk_get(&pdev->dev, NULL); |
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if (IS_ERR(mxc_rng->clk)) { |
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dev_err(&pdev->dev, "Could not get rng_clk!\n"); |
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return PTR_ERR(mxc_rng->clk); |
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} |
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err = clk_prepare_enable(mxc_rng->clk); |
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if (err) |
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return err; |
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mxc_rng->mem = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(mxc_rng->mem)) { |
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err = PTR_ERR(mxc_rng->mem); |
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goto err_ioremap; |
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} |
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err = hwrng_register(&mxc_rng->rng); |
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if (err) { |
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dev_err(&pdev->dev, "MXC RNGA registering failed (%d)\n", err); |
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goto err_ioremap; |
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} |
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return 0; |
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err_ioremap: |
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clk_disable_unprepare(mxc_rng->clk); |
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return err; |
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} |
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static int __exit mxc_rnga_remove(struct platform_device *pdev) |
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{ |
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struct mxc_rng *mxc_rng = platform_get_drvdata(pdev); |
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hwrng_unregister(&mxc_rng->rng); |
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clk_disable_unprepare(mxc_rng->clk); |
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return 0; |
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} |
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static const struct of_device_id mxc_rnga_of_match[] = { |
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{ .compatible = "fsl,imx21-rnga", }, |
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{ .compatible = "fsl,imx31-rnga", }, |
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{ /* sentinel */ }, |
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}; |
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MODULE_DEVICE_TABLE(of, mxc_rnga_of_match); |
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static struct platform_driver mxc_rnga_driver = { |
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.driver = { |
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.name = "mxc_rnga", |
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.of_match_table = mxc_rnga_of_match, |
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}, |
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.remove = __exit_p(mxc_rnga_remove), |
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}; |
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module_platform_driver_probe(mxc_rnga_driver, mxc_rnga_probe); |
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MODULE_AUTHOR("Freescale Semiconductor, Inc."); |
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MODULE_DESCRIPTION("H/W RNGA driver for i.MX"); |
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MODULE_LICENSE("GPL");
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