118 lines
3.2 KiB
C
118 lines
3.2 KiB
C
/*
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* Cortina Systems Gemini OF physmap add-on
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* Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
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*
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* This SoC has an elaborate flash control register, so we need to
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* detect and set it up when booting on this platform.
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*/
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#include <linux/export.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/mtd/map.h>
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#include <linux/mfd/syscon.h>
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#include <linux/regmap.h>
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#include <linux/bitops.h>
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#include "physmap_of_gemini.h"
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/*
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* The Flash-relevant parts of the global status register
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* These would also be relevant for a NAND driver.
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*/
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#define GLOBAL_STATUS 0x04
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#define FLASH_TYPE_MASK (0x3 << 24)
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#define FLASH_TYPE_NAND_2K (0x3 << 24)
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#define FLASH_TYPE_NAND_512 (0x2 << 24)
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#define FLASH_TYPE_PARALLEL (0x1 << 24)
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#define FLASH_TYPE_SERIAL (0x0 << 24)
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/* if parallel */
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#define FLASH_WIDTH_16BIT (1 << 23) /* else 8 bit */
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/* if serial */
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#define FLASH_ATMEL (1 << 23) /* else STM */
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#define FLASH_SIZE_MASK (0x3 << 21)
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#define NAND_256M (0x3 << 21) /* and more */
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#define NAND_128M (0x2 << 21)
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#define NAND_64M (0x1 << 21)
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#define NAND_32M (0x0 << 21)
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#define ATMEL_16M (0x3 << 21) /* and more */
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#define ATMEL_8M (0x2 << 21)
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#define ATMEL_4M_2M (0x1 << 21)
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#define ATMEL_1M (0x0 << 21) /* and less */
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#define STM_32M (1 << 22) /* and more */
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#define STM_16M (0 << 22) /* and less */
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#define FLASH_PARALLEL_HIGH_PIN_CNT (1 << 20) /* else low pin cnt */
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/* Miscellaneous Control Register */
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#define GLOBAL_MISC_CTRL 0x30
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#define FLASH_PADS_MASK 0x07
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#define NAND_PADS_DISABLE BIT(2)
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#define PFLASH_PADS_DISABLE BIT(1)
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#define SFLASH_PADS_DISABLE BIT(0)
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static const struct of_device_id syscon_match[] = {
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{ .compatible = "cortina,gemini-syscon" },
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{ },
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};
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int of_flash_probe_gemini(struct platform_device *pdev,
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struct device_node *np,
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struct map_info *map)
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{
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static struct regmap *rmap;
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struct device *dev = &pdev->dev;
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u32 val;
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int ret;
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/* Multiplatform guard */
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if (!of_device_is_compatible(np, "cortina,gemini-flash"))
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return 0;
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rmap = syscon_regmap_lookup_by_phandle(np, "syscon");
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if (IS_ERR(rmap)) {
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dev_err(dev, "no syscon\n");
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return PTR_ERR(rmap);
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}
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ret = regmap_read(rmap, GLOBAL_STATUS, &val);
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if (ret) {
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dev_err(dev, "failed to read global status register\n");
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return -ENODEV;
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}
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dev_dbg(dev, "global status reg: %08x\n", val);
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/*
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* It would be contradictory if a physmap flash was NOT parallel.
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*/
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if ((val & FLASH_TYPE_MASK) != FLASH_TYPE_PARALLEL) {
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dev_err(dev, "flash is not parallel\n");
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return -ENODEV;
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}
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/*
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* Complain if DT data and hardware definition is different.
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*/
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if (val & FLASH_WIDTH_16BIT) {
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if (map->bankwidth != 2)
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dev_warn(dev, "flash hardware say flash is 16 bit wide but DT says it is %d bits wide\n",
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map->bankwidth * 8);
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} else {
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if (map->bankwidth != 1)
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dev_warn(dev, "flash hardware say flash is 8 bit wide but DT says it is %d bits wide\n",
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map->bankwidth * 8);
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}
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/* Activate parallel (NOR flash) mode */
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ret = regmap_update_bits(rmap, GLOBAL_MISC_CTRL,
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FLASH_PADS_MASK,
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SFLASH_PADS_DISABLE | NAND_PADS_DISABLE);
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if (ret) {
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dev_err(dev, "unable to set up physmap pads\n");
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return -ENODEV;
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}
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dev_info(&pdev->dev, "initialized Gemini-specific physmap control\n");
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return 0;
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}
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