e96e2132f9
This adds a helper function for clk_get_by_name in cases where the clock is optional. Hopefully this helps point driver writers in the right direction. Also convert some existing users. Signed-off-by: Sean Anderson <seanga2@gmail.com> Reviewed-by: Neil Armstrong <narmstrong@baylibre.com> Reviewed-by: Simon Glass <sjg@chromium.org> Link: https://lore.kernel.org/r/20220115205247.566210-2-seanga2@gmail.com
122 lines
2.2 KiB
C
122 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
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*
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* Driver for Amlogic hardware random number generator
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*/
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#include <common.h>
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#include <clk.h>
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#include <dm.h>
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#include <rng.h>
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#include <asm/io.h>
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struct meson_rng_plat {
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fdt_addr_t base;
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struct clk clk;
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};
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/**
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* meson_rng_read() - fill buffer with random bytes
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*
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* @buffer: buffer to receive data
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* @size: size of buffer
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*
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* Return: 0
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*/
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static int meson_rng_read(struct udevice *dev, void *data, size_t len)
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{
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struct meson_rng_plat *pdata = dev_get_plat(dev);
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char *buffer = (char *)data;
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while (len) {
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u32 rand = readl(pdata->base);
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size_t step;
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if (len >= 4)
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step = 4;
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else
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step = len;
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memcpy(buffer, &rand, step);
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buffer += step;
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len -= step;
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}
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return 0;
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}
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/**
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* meson_rng_probe() - probe rng device
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*
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* @dev: device
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* Return: 0 if ok
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*/
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static int meson_rng_probe(struct udevice *dev)
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{
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struct meson_rng_plat *pdata = dev_get_plat(dev);
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int err;
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err = clk_enable(&pdata->clk);
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if (err)
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return err;
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return 0;
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}
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/**
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* meson_rng_remove() - deinitialize rng device
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*
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* @dev: device
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* Return: 0 if ok
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*/
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static int meson_rng_remove(struct udevice *dev)
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{
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struct meson_rng_plat *pdata = dev_get_plat(dev);
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return clk_disable(&pdata->clk);
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}
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/**
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* meson_rng_of_to_plat() - transfer device tree data to plaform data
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*
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* @dev: device
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* Return: 0 if ok
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*/
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static int meson_rng_of_to_plat(struct udevice *dev)
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{
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struct meson_rng_plat *pdata = dev_get_plat(dev);
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int err;
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pdata->base = dev_read_addr(dev);
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if (!pdata->base)
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return -ENODEV;
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/* Get optional "core" clock */
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err = clk_get_by_name_optional(dev, "core", &pdata->clk);
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if (err)
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return err;
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return 0;
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}
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static const struct dm_rng_ops meson_rng_ops = {
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.read = meson_rng_read,
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};
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static const struct udevice_id meson_rng_match[] = {
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{
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.compatible = "amlogic,meson-rng",
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},
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{},
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};
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U_BOOT_DRIVER(meson_rng) = {
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.name = "meson-rng",
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.id = UCLASS_RNG,
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.of_match = meson_rng_match,
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.ops = &meson_rng_ops,
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.probe = meson_rng_probe,
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.remove = meson_rng_remove,
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.plat_auto = sizeof(struct meson_rng_plat),
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.of_to_plat = meson_rng_of_to_plat,
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};
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