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119 lines
2.9 KiB
119 lines
2.9 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (C) 2006-2007 PA Semi, Inc |
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* |
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* Maintained by: Olof Johansson <[email protected]> |
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* |
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* Driver for the PWRficient onchip rng |
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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/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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#define SDCRNG_CTL_REG 0x00 |
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#define SDCRNG_CTL_FVLD_M 0x0000f000 |
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#define SDCRNG_CTL_FVLD_S 12 |
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#define SDCRNG_CTL_KSZ 0x00000800 |
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#define SDCRNG_CTL_RSRC_CRG 0x00000010 |
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#define SDCRNG_CTL_RSRC_RRG 0x00000000 |
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#define SDCRNG_CTL_CE 0x00000004 |
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#define SDCRNG_CTL_RE 0x00000002 |
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#define SDCRNG_CTL_DR 0x00000001 |
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#define SDCRNG_CTL_SELECT_RRG_RNG (SDCRNG_CTL_RE | SDCRNG_CTL_RSRC_RRG) |
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#define SDCRNG_CTL_SELECT_CRG_RNG (SDCRNG_CTL_CE | SDCRNG_CTL_RSRC_CRG) |
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#define SDCRNG_VAL_REG 0x20 |
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#define MODULE_NAME "pasemi_rng" |
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static int pasemi_rng_data_present(struct hwrng *rng, int wait) |
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{ |
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void __iomem *rng_regs = (void __iomem *)rng->priv; |
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int data, i; |
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for (i = 0; i < 20; i++) { |
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data = (in_le32(rng_regs + SDCRNG_CTL_REG) |
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& SDCRNG_CTL_FVLD_M) ? 1 : 0; |
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if (data || !wait) |
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break; |
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udelay(10); |
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} |
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return data; |
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} |
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static int pasemi_rng_data_read(struct hwrng *rng, u32 *data) |
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{ |
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void __iomem *rng_regs = (void __iomem *)rng->priv; |
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*data = in_le32(rng_regs + SDCRNG_VAL_REG); |
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return 4; |
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} |
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static int pasemi_rng_init(struct hwrng *rng) |
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{ |
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void __iomem *rng_regs = (void __iomem *)rng->priv; |
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u32 ctl; |
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ctl = SDCRNG_CTL_DR | SDCRNG_CTL_SELECT_RRG_RNG | SDCRNG_CTL_KSZ; |
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out_le32(rng_regs + SDCRNG_CTL_REG, ctl); |
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out_le32(rng_regs + SDCRNG_CTL_REG, ctl & ~SDCRNG_CTL_DR); |
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return 0; |
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} |
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static void pasemi_rng_cleanup(struct hwrng *rng) |
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{ |
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void __iomem *rng_regs = (void __iomem *)rng->priv; |
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u32 ctl; |
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ctl = SDCRNG_CTL_RE | SDCRNG_CTL_CE; |
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out_le32(rng_regs + SDCRNG_CTL_REG, |
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in_le32(rng_regs + SDCRNG_CTL_REG) & ~ctl); |
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} |
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static struct hwrng pasemi_rng = { |
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.name = MODULE_NAME, |
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.init = pasemi_rng_init, |
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.cleanup = pasemi_rng_cleanup, |
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.data_present = pasemi_rng_data_present, |
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.data_read = pasemi_rng_data_read, |
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}; |
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static int rng_probe(struct platform_device *pdev) |
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{ |
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void __iomem *rng_regs; |
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rng_regs = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(rng_regs)) |
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return PTR_ERR(rng_regs); |
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pasemi_rng.priv = (unsigned long)rng_regs; |
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pr_info("Registering PA Semi RNG\n"); |
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return devm_hwrng_register(&pdev->dev, &pasemi_rng); |
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} |
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static const struct of_device_id rng_match[] = { |
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{ .compatible = "1682m-rng", }, |
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{ .compatible = "pasemi,pwrficient-rng", }, |
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{ }, |
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}; |
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MODULE_DEVICE_TABLE(of, rng_match); |
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static struct platform_driver rng_driver = { |
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.driver = { |
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.name = "pasemi-rng", |
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.of_match_table = rng_match, |
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}, |
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.probe = rng_probe, |
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}; |
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module_platform_driver(rng_driver); |
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MODULE_LICENSE("GPL"); |
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MODULE_AUTHOR("Egor Martovetsky <[email protected]>"); |
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MODULE_DESCRIPTION("H/W RNG driver for PA Semi processor");
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