drivers/firmware/broadcom/bcm47xx_nvram.c

Source file repositories/reference/linux-study-clean/drivers/firmware/broadcom/bcm47xx_nvram.c

File Facts

System
Linux kernel
Corpus path
drivers/firmware/broadcom/bcm47xx_nvram.c
Extension
.c
Size
6207 bytes
Lines
258
Domain
Driver Families
Bucket
drivers/firmware
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct nvram_header {
	u32 magic;
	u32 len;
	u32 crc_ver_init;	/* 0:7 crc, 8:15 ver, 16:31 sdram_init */
	u32 config_refresh;	/* 0:15 sdram_config, 16:31 sdram_refresh */
	u32 config_ncdl;	/* ncdl values for memc */
};

static char nvram_buf[NVRAM_SPACE];
static size_t nvram_len;
static const u32 nvram_sizes[] = {0x6000, 0x8000, 0xF000, 0x10000};

/**
 * bcm47xx_nvram_is_valid - check for a valid NVRAM at specified memory
 */
static bool bcm47xx_nvram_is_valid(void __iomem *nvram)
{
	return ((struct nvram_header *)nvram)->magic == NVRAM_MAGIC;
}

/**
 * bcm47xx_nvram_copy - copy NVRAM to internal buffer
 */
static void bcm47xx_nvram_copy(void __iomem *nvram_start, size_t res_size)
{
	struct nvram_header __iomem *header = nvram_start;
	size_t copy_size;

	copy_size = header->len;
	if (copy_size > res_size) {
		pr_err("The nvram size according to the header seems to be bigger than the partition on flash\n");
		copy_size = res_size;
	}
	if (copy_size >= NVRAM_SPACE) {
		pr_err("nvram on flash (%zu bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
		       copy_size, NVRAM_SPACE - 1);
		copy_size = NVRAM_SPACE - 1;
	}

	__ioread32_copy(nvram_buf, nvram_start, DIV_ROUND_UP(copy_size, 4));
	nvram_buf[NVRAM_SPACE - 1] = '\0';
	nvram_len = copy_size;
}

/**
 * bcm47xx_nvram_find_and_copy - find NVRAM on flash mapping & copy it
 */
static int bcm47xx_nvram_find_and_copy(void __iomem *flash_start, size_t res_size)
{
	size_t flash_size;
	size_t offset;
	int i;

	if (nvram_len) {
		pr_warn("nvram already initialized\n");
		return -EEXIST;
	}

	/* TODO: when nvram is on nand flash check for bad blocks first. */

	/* Try every possible flash size and check for NVRAM at its end */
	for (flash_size = FLASH_MIN; flash_size <= res_size; flash_size <<= 1) {
		for (i = 0; i < ARRAY_SIZE(nvram_sizes); i++) {
			offset = flash_size - nvram_sizes[i];
			if (bcm47xx_nvram_is_valid(flash_start + offset))
				goto found;
		}
	}

	/* Try embedded NVRAM at 4 KB and 1 KB as last resorts */

	offset = 4096;
	if (bcm47xx_nvram_is_valid(flash_start + offset))
		goto found;

	offset = 1024;
	if (bcm47xx_nvram_is_valid(flash_start + offset))
		goto found;

	pr_err("no nvram found\n");
	return -ENXIO;

found:
	bcm47xx_nvram_copy(flash_start + offset, res_size - offset);

	return 0;
}

int bcm47xx_nvram_init_from_iomem(void __iomem *nvram_start, size_t res_size)
{

Annotation

Implementation Notes