diff options
Diffstat (limited to 'drivers/edac')
| -rw-r--r-- | drivers/edac/mpc85xx_edac.c | 146 |
1 files changed, 138 insertions, 8 deletions
diff --git a/drivers/edac/mpc85xx_edac.c b/drivers/edac/mpc85xx_edac.c index 6d0114a..517042f 100644 --- a/drivers/edac/mpc85xx_edac.c +++ b/drivers/edac/mpc85xx_edac.c @@ -668,6 +668,111 @@ static struct of_platform_driver mpc85xx_l2_err_driver = { /**************************** MC Err device ***************************/ +/* + * Taken from table 8-55 in the MPC8641 User's Manual and/or 9-61 in the + * MPC8572 User's Manual. Each line represents a syndrome bit column as a + * 64-bit value, but split into an upper and lower 32-bit chunk. The labels + * below correspond to Freescale's manuals. + */ +static unsigned int ecc_table[16] = { + /* MSB LSB */ + /* [0:31] [32:63] */ + 0xf00fe11e, 0xc33c0ff7, /* Syndrome bit 7 */ + 0x00ff00ff, 0x00fff0ff, + 0x0f0f0f0f, 0x0f0fff00, + 0x11113333, 0x7777000f, + 0x22224444, 0x8888222f, + 0x44448888, 0xffff4441, + 0x8888ffff, 0x11118882, + 0xffff1111, 0x22221114, /* Syndrome bit 0 */ +}; + +/* + * Calculate the correct ECC value for a 64-bit value specified by high:low + */ +static u8 calculate_ecc(u32 high, u32 low) +{ + u32 mask_low; + u32 mask_high; + int bit_cnt; + u8 ecc = 0; + int i; + int j; + + for (i = 0; i < 8; i++) { + mask_high = ecc_table[i * 2]; + mask_low = ecc_table[i * 2 + 1]; + bit_cnt = 0; + + for (j = 0; j < 32; j++) { + if ((mask_high >> j) & 1) + bit_cnt ^= (high >> j) & 1; + if ((mask_low >> j) & 1) + bit_cnt ^= (low >> j) & 1; + } + + ecc |= bit_cnt << i; + } + + return ecc; +} + +/* + * Create the syndrome code which is generated if the data line specified by + * 'bit' failed. Eg generate an 8-bit codes seen in Table 8-55 in the MPC8641 + * User's Manual and 9-61 in the MPC8572 User's Manual. + */ +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; + } + } +} + static void mpc85xx_mc_check(struct mem_ctl_info *mci) { struct mpc85xx_mc_pdata *pdata = mci->pvt_info; @@ -678,6 +783,10 @@ static void mpc85xx_mc_check(struct mem_ctl_info *mci) u32 err_addr; u32 pfn; int row_index; + u32 cap_high; + u32 cap_low; + int bad_data_bit; + int bad_ecc_bit; err_detect = in_be32(pdata->mc_vbase + MPC85XX_MC_ERR_DETECT); if (!err_detect) @@ -711,14 +820,35 @@ static void mpc85xx_mc_check(struct mem_ctl_info *mci) break; } - mpc85xx_mc_printk(mci, KERN_ERR, "Capture Data High: %#8.8x\n", - in_be32(pdata->mc_vbase + - MPC85XX_MC_CAPTURE_DATA_HI)); - mpc85xx_mc_printk(mci, KERN_ERR, "Capture Data Low: %#8.8x\n", - in_be32(pdata->mc_vbase + - MPC85XX_MC_CAPTURE_DATA_LO)); - mpc85xx_mc_printk(mci, KERN_ERR, "syndrome: %#2.2x\n", syndrome); - mpc85xx_mc_printk(mci, KERN_ERR, "err addr: %#8.8x\n", err_addr); + cap_high = in_be32(pdata->mc_vbase + MPC85XX_MC_CAPTURE_DATA_HI); + cap_low = in_be32(pdata->mc_vbase + MPC85XX_MC_CAPTURE_DATA_LO); + + /* + * Analyze single-bit errors on 64-bit wide buses + * TODO: Add support for 32-bit wide buses + */ + if ((err_detect & DDR_EDE_SBE) && (bus_width == 64)) { + sbe_ecc_decode(cap_high, cap_low, syndrome, + &bad_data_bit, &bad_ecc_bit); + + if (bad_data_bit != -1) + mpc85xx_mc_printk(mci, KERN_ERR, + "Faulty Data bit: %d\n", bad_data_bit); + if (bad_ecc_bit != -1) + mpc85xx_mc_printk(mci, KERN_ERR, + "Faulty ECC bit: %d\n", bad_ecc_bit); + + mpc85xx_mc_printk(mci, KERN_ERR, + "Expected Data / ECC:\t%#8.8x_%08x / %#2.2x\n", + cap_high ^ (1 << (bad_data_bit - 32)), + cap_low ^ (1 << bad_data_bit), + syndrome ^ (1 << bad_ecc_bit)); + } + + mpc85xx_mc_printk(mci, KERN_ERR, + "Captured Data / ECC:\t%#8.8x_%08x / %#2.2x\n", + cap_high, cap_low, syndrome); + mpc85xx_mc_printk(mci, KERN_ERR, "Err addr: %#8.8x\n", err_addr); mpc85xx_mc_printk(mci, KERN_ERR, "PFN: %#8.8x\n", pfn); /* we are out of range */ |
