150 lines
3.8 KiB
C
150 lines
3.8 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Socfpga Reset Controller Driver
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*
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* Copyright 2014 Steffen Trumtrar <s.trumtrar@pengutronix.de>
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*
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* based on
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* Allwinner SoCs Reset Controller driver
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*
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* Copyright 2013 Maxime Ripard
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*
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* Maxime Ripard <maxime.ripard@free-electrons.com>
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*/
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#include <common.h>
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#include <dm.h>
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#include <dm/of_access.h>
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#include <reset-uclass.h>
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#include <linux/bitops.h>
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#include <linux/io.h>
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#include <linux/sizes.h>
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#define BANK_INCREMENT 4
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#define NR_BANKS 8
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struct socfpga_reset_data {
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void __iomem *modrst_base;
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};
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/*
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* For compatibility with Kernels that don't support peripheral reset, this
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* driver can keep the old behaviour of not asserting peripheral reset before
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* starting the OS and deasserting all peripheral resets (enabling all
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* peripherals).
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*
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* For that, the reset driver checks the environment variable
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* "socfpga_legacy_reset_compat". If this variable is '1', perihperals are not
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* reset again once taken out of reset and all peripherals in 'permodrst' are
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* taken out of reset before booting into the OS.
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* Note that this should be required for gen5 systems only that are running
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* Linux kernels without proper peripheral reset support for all drivers used.
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*/
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static bool socfpga_reset_keep_enabled(void)
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{
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#if !defined(CONFIG_SPL_BUILD) || CONFIG_IS_ENABLED(ENV_SUPPORT)
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const char *env_str;
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long val;
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env_str = env_get("socfpga_legacy_reset_compat");
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if (env_str) {
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val = simple_strtol(env_str, NULL, 0);
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if (val == 1)
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return true;
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}
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#endif
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return false;
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}
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static int socfpga_reset_assert(struct reset_ctl *reset_ctl)
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{
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struct socfpga_reset_data *data = dev_get_priv(reset_ctl->dev);
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int id = reset_ctl->id;
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int reg_width = sizeof(u32);
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int bank = id / (reg_width * BITS_PER_BYTE);
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int offset = id % (reg_width * BITS_PER_BYTE);
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setbits_le32(data->modrst_base + (bank * BANK_INCREMENT), BIT(offset));
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return 0;
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}
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static int socfpga_reset_deassert(struct reset_ctl *reset_ctl)
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{
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struct socfpga_reset_data *data = dev_get_priv(reset_ctl->dev);
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int id = reset_ctl->id;
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int reg_width = sizeof(u32);
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int bank = id / (reg_width * BITS_PER_BYTE);
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int offset = id % (reg_width * BITS_PER_BYTE);
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clrbits_le32(data->modrst_base + (bank * BANK_INCREMENT), BIT(offset));
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return 0;
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}
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static int socfpga_reset_request(struct reset_ctl *reset_ctl)
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{
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debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__,
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reset_ctl, reset_ctl->dev, reset_ctl->id);
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return 0;
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}
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static int socfpga_reset_free(struct reset_ctl *reset_ctl)
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{
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debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__, reset_ctl,
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reset_ctl->dev, reset_ctl->id);
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return 0;
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}
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static const struct reset_ops socfpga_reset_ops = {
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.request = socfpga_reset_request,
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.free = socfpga_reset_free,
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.rst_assert = socfpga_reset_assert,
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.rst_deassert = socfpga_reset_deassert,
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};
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static int socfpga_reset_probe(struct udevice *dev)
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{
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struct socfpga_reset_data *data = dev_get_priv(dev);
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const void *blob = gd->fdt_blob;
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int node = dev_of_offset(dev);
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u32 modrst_offset;
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void __iomem *membase;
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membase = devfdt_get_addr_ptr(dev);
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modrst_offset = fdtdec_get_int(blob, node, "altr,modrst-offset", 0x10);
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data->modrst_base = membase + modrst_offset;
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return 0;
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}
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static int socfpga_reset_remove(struct udevice *dev)
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{
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struct socfpga_reset_data *data = dev_get_priv(dev);
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if (socfpga_reset_keep_enabled()) {
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puts("Deasserting all peripheral resets\n");
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writel(0, data->modrst_base + 4);
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}
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return 0;
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}
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static const struct udevice_id socfpga_reset_match[] = {
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{ .compatible = "altr,rst-mgr" },
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{ /* sentinel */ },
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};
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U_BOOT_DRIVER(socfpga_reset) = {
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.name = "socfpga-reset",
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.id = UCLASS_RESET,
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.of_match = socfpga_reset_match,
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.probe = socfpga_reset_probe,
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.priv_auto_alloc_size = sizeof(struct socfpga_reset_data),
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.ops = &socfpga_reset_ops,
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.remove = socfpga_reset_remove,
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.flags = DM_FLAG_OS_PREPARE,
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};
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