drivers/edac/fsl_ddr_edac.c

Source file repositories/reference/linux-study-clean/drivers/edac/fsl_ddr_edac.c

File Facts

System
Linux kernel
Corpus path
drivers/edac/fsl_ddr_edac.c
Extension
.c
Size
16596 bytes
Lines
674
Domain
Driver Families
Bucket
drivers/edac
Inferred role
Driver Families: implementation source
Status
source 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

static u8 syndrome_from_bit(unsigned int bit) {
	int i;
	u8 syndrome = 0;

	/*
	 * Cycle through the upper or lower 32-bit portion of each value in
	 * ecc_table depending on if 'bit' is in the upper or lower half of
	 * 64-bit data.
	 */
	for (i = bit < 32; i < 16; i += 2)
		syndrome |= ((ecc_table[i] >> (bit % 32)) & 1) << (i / 2);

	return syndrome;
}

/*
 * Decode data and ecc syndrome to determine what went wrong
 * Note: This can only decode single-bit errors
 */
static void sbe_ecc_decode(u32 cap_high, u32 cap_low, u32 cap_ecc,
		       int *bad_data_bit, int *bad_ecc_bit)
{
	int i;
	u8 syndrome;

	*bad_data_bit = -1;
	*bad_ecc_bit = -1;

	/*
	 * Calculate the ECC of the captured data and XOR it with the captured
	 * ECC to find an ECC syndrome value we can search for
	 */
	syndrome = calculate_ecc(cap_high, cap_low) ^ cap_ecc;

	/* Check if a data line is stuck... */
	for (i = 0; i < 64; i++) {
		if (syndrome == syndrome_from_bit(i)) {
			*bad_data_bit = i;
			return;
		}
	}

	/* If data is correct, check ECC bits for errors... */
	for (i = 0; i < 8; i++) {
		if ((syndrome >> i) & 0x1) {
			*bad_ecc_bit = i;
			return;
		}
	}
}

#define make64(high, low) (((u64)(high) << 32) | (low))

static void fsl_mc_check(struct mem_ctl_info *mci)
{
	struct fsl_mc_pdata *pdata = mci->pvt_info;
	struct csrow_info *csrow;
	u32 bus_width;
	u32 err_detect;
	u32 syndrome;
	u64 err_addr;
	u32 pfn;
	int row_index;
	u32 cap_high;
	u32 cap_low;
	int bad_data_bit;
	int bad_ecc_bit;

	err_detect = ddr_in32(pdata, FSL_MC_ERR_DETECT);
	if (!err_detect)
		return;

	fsl_mc_printk(mci, KERN_ERR, "Err Detect Register: %#8.8x\n",
		      err_detect);

	/* no more processing if not ECC bit errors */
	if (!(err_detect & (DDR_EDE_SBE | DDR_EDE_MBE))) {
		ddr_out32(pdata, FSL_MC_ERR_DETECT, err_detect);
		return;
	}

	syndrome = ddr_in32(pdata, FSL_MC_CAPTURE_ECC);

	/* Mask off appropriate bits of syndrome based on bus width */
	bus_width = (ddr_in32(pdata, FSL_MC_DDR_SDRAM_CFG) &
		     DSC_DBW_MASK) ? 32 : 64;
	if (bus_width == 64)
		syndrome &= 0xff;
	else
		syndrome &= 0xffff;

Annotation

Implementation Notes