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207775f7e1
DT binding for Broadcom's NVRAM supports specifying NVMEM cells as NVMEM device (provider) subnodes. Look for such subnodes when collecing NVMEM cells. This allows NVMEM consumers to use NVRAM variables. Signed-off-by: Rafał Miłecki <rafal@milecki.pl> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20220429162701.2222-3-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
171 lines
3.7 KiB
C
171 lines
3.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2021 Rafał Miłecki <rafal@milecki.pl>
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*/
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#include <linux/io.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/nvmem-consumer.h>
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#include <linux/nvmem-provider.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#define NVRAM_MAGIC "FLSH"
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struct brcm_nvram {
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struct device *dev;
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void __iomem *base;
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struct nvmem_cell_info *cells;
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int ncells;
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};
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struct brcm_nvram_header {
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char magic[4];
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__le32 len;
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__le32 crc_ver_init; /* 0:7 crc, 8:15 ver, 16:31 sdram_init */
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__le32 config_refresh; /* 0:15 sdram_config, 16:31 sdram_refresh */
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__le32 config_ncdl; /* ncdl values for memc */
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};
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static int brcm_nvram_read(void *context, unsigned int offset, void *val,
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size_t bytes)
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{
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struct brcm_nvram *priv = context;
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u8 *dst = val;
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while (bytes--)
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*dst++ = readb(priv->base + offset++);
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return 0;
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}
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static int brcm_nvram_add_cells(struct brcm_nvram *priv, uint8_t *data,
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size_t len)
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{
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struct device *dev = priv->dev;
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char *var, *value, *eq;
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int idx;
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priv->ncells = 0;
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for (var = data + sizeof(struct brcm_nvram_header);
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var < (char *)data + len && *var;
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var += strlen(var) + 1) {
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priv->ncells++;
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}
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priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL);
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if (!priv->cells)
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return -ENOMEM;
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for (var = data + sizeof(struct brcm_nvram_header), idx = 0;
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var < (char *)data + len && *var;
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var = value + strlen(value) + 1, idx++) {
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eq = strchr(var, '=');
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if (!eq)
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break;
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*eq = '\0';
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value = eq + 1;
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priv->cells[idx].name = devm_kstrdup(dev, var, GFP_KERNEL);
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if (!priv->cells[idx].name)
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return -ENOMEM;
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priv->cells[idx].offset = value - (char *)data;
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priv->cells[idx].bytes = strlen(value);
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priv->cells[idx].np = of_get_child_by_name(dev->of_node, priv->cells[idx].name);
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}
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return 0;
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}
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static int brcm_nvram_parse(struct brcm_nvram *priv)
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{
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struct device *dev = priv->dev;
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struct brcm_nvram_header header;
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uint8_t *data;
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size_t len;
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int err;
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memcpy_fromio(&header, priv->base, sizeof(header));
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if (memcmp(header.magic, NVRAM_MAGIC, 4)) {
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dev_err(dev, "Invalid NVRAM magic\n");
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return -EINVAL;
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}
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len = le32_to_cpu(header.len);
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data = kcalloc(1, len, GFP_KERNEL);
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memcpy_fromio(data, priv->base, len);
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data[len - 1] = '\0';
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err = brcm_nvram_add_cells(priv, data, len);
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if (err) {
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dev_err(dev, "Failed to add cells: %d\n", err);
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return err;
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}
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kfree(data);
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return 0;
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}
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static int brcm_nvram_probe(struct platform_device *pdev)
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{
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struct nvmem_config config = {
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.name = "brcm-nvram",
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.reg_read = brcm_nvram_read,
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};
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struct device *dev = &pdev->dev;
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struct resource *res;
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struct brcm_nvram *priv;
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int err;
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priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->dev = dev;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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priv->base = devm_ioremap_resource(dev, res);
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if (IS_ERR(priv->base))
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return PTR_ERR(priv->base);
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err = brcm_nvram_parse(priv);
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if (err)
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return err;
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config.dev = dev;
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config.cells = priv->cells;
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config.ncells = priv->ncells;
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config.priv = priv;
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config.size = resource_size(res);
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return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config));
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}
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static const struct of_device_id brcm_nvram_of_match_table[] = {
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{ .compatible = "brcm,nvram", },
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{},
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};
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static struct platform_driver brcm_nvram_driver = {
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.probe = brcm_nvram_probe,
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.driver = {
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.name = "brcm_nvram",
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.of_match_table = brcm_nvram_of_match_table,
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},
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};
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static int __init brcm_nvram_init(void)
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{
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return platform_driver_register(&brcm_nvram_driver);
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}
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subsys_initcall_sync(brcm_nvram_init);
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MODULE_AUTHOR("Rafał Miłecki");
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MODULE_LICENSE("GPL");
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MODULE_DEVICE_TABLE(of, brcm_nvram_of_match_table);
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