tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Cortina Systems Gemini OF physmap add-on
4 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
5 *
6 * This SoC has an elaborate flash control register, so we need to
7 * detect and set it up when booting on this platform.
8 */
9#include <linux/export.h>
10#include <linux/of.h>
11#include <linux/of_device.h>
12#include <linux/mtd/map.h>
13#include <linux/mfd/syscon.h>
14#include <linux/regmap.h>
15#include <linux/bitops.h>
16#include "physmap_of_gemini.h"
17
18/*
19 * The Flash-relevant parts of the global status register
20 * These would also be relevant for a NAND driver.
21 */
22#define GLOBAL_STATUS 0x04
23#define FLASH_TYPE_MASK (0x3 << 24)
24#define FLASH_TYPE_NAND_2K (0x3 << 24)
25#define FLASH_TYPE_NAND_512 (0x2 << 24)
26#define FLASH_TYPE_PARALLEL (0x1 << 24)
27#define FLASH_TYPE_SERIAL (0x0 << 24)
28/* if parallel */
29#define FLASH_WIDTH_16BIT (1 << 23) /* else 8 bit */
30/* if serial */
31#define FLASH_ATMEL (1 << 23) /* else STM */
32
33#define FLASH_SIZE_MASK (0x3 << 21)
34#define NAND_256M (0x3 << 21) /* and more */
35#define NAND_128M (0x2 << 21)
36#define NAND_64M (0x1 << 21)
37#define NAND_32M (0x0 << 21)
38#define ATMEL_16M (0x3 << 21) /* and more */
39#define ATMEL_8M (0x2 << 21)
40#define ATMEL_4M_2M (0x1 << 21)
41#define ATMEL_1M (0x0 << 21) /* and less */
42#define STM_32M (1 << 22) /* and more */
43#define STM_16M (0 << 22) /* and less */
44
45#define FLASH_PARALLEL_HIGH_PIN_CNT (1 << 20) /* else low pin cnt */
46
47static const struct of_device_id syscon_match[] = {
48 { .compatible = "cortina,gemini-syscon" },
49 { },
50};
51
52int of_flash_probe_gemini(struct platform_device *pdev,
53 struct device_node *np,
54 struct map_info *map)
55{
56 struct regmap *rmap;
57 struct device *dev = &pdev->dev;
58 u32 val;
59 int ret;
60
61 /* Multiplatform guard */
62 if (!of_device_is_compatible(np, "cortina,gemini-flash"))
63 return 0;
64
65 rmap = syscon_regmap_lookup_by_phandle(np, "syscon");
66 if (IS_ERR(rmap)) {
67 dev_err(dev, "no syscon\n");
68 return PTR_ERR(rmap);
69 }
70
71 ret = regmap_read(rmap, GLOBAL_STATUS, &val);
72 if (ret) {
73 dev_err(dev, "failed to read global status register\n");
74 return -ENODEV;
75 }
76 dev_dbg(dev, "global status reg: %08x\n", val);
77
78 /*
79 * It would be contradictory if a physmap flash was NOT parallel.
80 */
81 if ((val & FLASH_TYPE_MASK) != FLASH_TYPE_PARALLEL) {
82 dev_err(dev, "flash is not parallel\n");
83 return -ENODEV;
84 }
85
86 /*
87 * Complain if DT data and hardware definition is different.
88 */
89 if (val & FLASH_WIDTH_16BIT) {
90 if (map->bankwidth != 2)
91 dev_warn(dev, "flash hardware say flash is 16 bit wide but DT says it is %d bits wide\n",
92 map->bankwidth * 8);
93 } else {
94 if (map->bankwidth != 1)
95 dev_warn(dev, "flash hardware say flash is 8 bit wide but DT says it is %d bits wide\n",
96 map->bankwidth * 8);
97 }
98
99 dev_info(&pdev->dev, "initialized Gemini-specific physmap control\n");
100
101 return 0;
102}