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authorJeff Roberson <jroberson@jroberson.net>2009-10-26 16:50:09 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-10-29 07:39:30 -0700
commit156edd4aaa819ec5867ced83c7b8dba9193789ea (patch)
tree58066a63e881f3dc359d8d439f04ffece0a34e6a /drivers/edac/i5400_edac.c
parent8c85dd8730bfb696e691145335f884c7baef8277 (diff)
downloadlinaro-lsk-156edd4aaa819ec5867ced83c7b8dba9193789ea.tar.gz
edac: i5400 fix csrow mapping
The i5400 EDAC driver has several bugs with chip-select row computation which most likely lead to bugs in detailed error reporting. Attempts to contact the authors have gone mostly unanswered so I am presenting my diff here. I do not subscribe to lkml and would appreciate being kept in the cc. The most egregious problem was miscalculating the addresses of MTR registers after register 0 by assuming they are 32bit rather than 16. This caused the driver to miss half of the memories. Most motherboards tend to have only 8 dimm slots and not 16, so this may not have been noticed before. Further, the row calculations multiplied the number of dimms several times, ultimately ending up with a maximum row of 32. The chipset only supports 4 dimms in each of 4 channels, so csrow could not be higher than 4 unless you use a row per-rank with dual-rank dimms. I opted to eliminate this behavior as it is confusing to the user and the error reporting works by slot and not rank. This gives a much clearer view of memory by slot and channel in /sys. Signed-off-by: Jeff Roberson <jroberson@jroberson.net> Signed-off-by: Doug Thompson <dougthompson@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/edac/i5400_edac.c')
-rw-r--r--drivers/edac/i5400_edac.c89
1 files changed, 28 insertions, 61 deletions
diff --git a/drivers/edac/i5400_edac.c b/drivers/edac/i5400_edac.c
index b08b6d8e2dc..f99d10655ed 100644
--- a/drivers/edac/i5400_edac.c
+++ b/drivers/edac/i5400_edac.c
@@ -46,9 +46,10 @@
/* Limits for i5400 */
#define NUM_MTRS_PER_BRANCH 4
#define CHANNELS_PER_BRANCH 2
+#define MAX_DIMMS_PER_CHANNEL NUM_MTRS_PER_BRANCH
#define MAX_CHANNELS 4
-#define MAX_DIMMS (MAX_CHANNELS * 4) /* Up to 4 DIMM's per channel */
-#define MAX_CSROWS (MAX_DIMMS * 2) /* max possible csrows per channel */
+/* max possible csrows per channel */
+#define MAX_CSROWS (MAX_DIMMS_PER_CHANNEL)
/* Device 16,
* Function 0: System Address
@@ -331,7 +332,6 @@ static const struct i5400_dev_info i5400_devs[] = {
struct i5400_dimm_info {
int megabytes; /* size, 0 means not present */
- int dual_rank;
};
/* driver private data structure */
@@ -849,11 +849,9 @@ static int determine_mtr(struct i5400_pvt *pvt, int csrow, int channel)
int n;
/* There is one MTR for each slot pair of FB-DIMMs,
- Each slot may have one or two ranks (2 csrows),
Each slot pair may be at branch 0 or branch 1.
- So, csrow should be divided by eight
*/
- n = csrow >> 3;
+ n = csrow;
if (n >= NUM_MTRS_PER_BRANCH) {
debugf0("ERROR: trying to access an invalid csrow: %d\n",
@@ -905,25 +903,22 @@ static void handle_channel(struct i5400_pvt *pvt, int csrow, int channel,
amb_present_reg = determine_amb_present_reg(pvt, channel);
/* Determine if there is a DIMM present in this DIMM slot */
- if (amb_present_reg & (1 << (csrow >> 1))) {
- dinfo->dual_rank = MTR_DIMM_RANK(mtr);
-
- if (!((dinfo->dual_rank == 0) &&
- ((csrow & 0x1) == 0x1))) {
- /* Start with the number of bits for a Bank
- * on the DRAM */
- addrBits = MTR_DRAM_BANKS_ADDR_BITS(mtr);
- /* Add thenumber of ROW bits */
- addrBits += MTR_DIMM_ROWS_ADDR_BITS(mtr);
- /* add the number of COLUMN bits */
- addrBits += MTR_DIMM_COLS_ADDR_BITS(mtr);
-
- addrBits += 6; /* add 64 bits per DIMM */
- addrBits -= 20; /* divide by 2^^20 */
- addrBits -= 3; /* 8 bits per bytes */
-
- dinfo->megabytes = 1 << addrBits;
- }
+ if (amb_present_reg & (1 << csrow)) {
+ /* Start with the number of bits for a Bank
+ * on the DRAM */
+ addrBits = MTR_DRAM_BANKS_ADDR_BITS(mtr);
+ /* Add thenumber of ROW bits */
+ addrBits += MTR_DIMM_ROWS_ADDR_BITS(mtr);
+ /* add the number of COLUMN bits */
+ addrBits += MTR_DIMM_COLS_ADDR_BITS(mtr);
+ /* add the number of RANK bits */
+ addrBits += MTR_DIMM_RANK(mtr);
+
+ addrBits += 6; /* add 64 bits per DIMM */
+ addrBits -= 20; /* divide by 2^^20 */
+ addrBits -= 3; /* 8 bits per bytes */
+
+ dinfo->megabytes = 1 << addrBits;
}
}
}
@@ -951,12 +946,12 @@ static void calculate_dimm_size(struct i5400_pvt *pvt)
return;
}
- /* Scan all the actual CSROWS (which is # of DIMMS * 2)
+ /* Scan all the actual CSROWS
* and calculate the information for each DIMM
* Start with the highest csrow first, to display it first
* and work toward the 0th csrow
*/
- max_csrows = pvt->maxdimmperch * 2;
+ max_csrows = pvt->maxdimmperch;
for (csrow = max_csrows - 1; csrow >= 0; csrow--) {
/* on an odd csrow, first output a 'boundary' marker,
@@ -1064,7 +1059,7 @@ static void i5400_get_mc_regs(struct mem_ctl_info *mci)
/* Get the set of MTR[0-3] regs by each branch */
for (slot_row = 0; slot_row < NUM_MTRS_PER_BRANCH; slot_row++) {
- int where = MTR0 + (slot_row * sizeof(u32));
+ int where = MTR0 + (slot_row * sizeof(u16));
/* Branch 0 set of MTR registers */
pci_read_config_word(pvt->branch_0, where,
@@ -1146,7 +1141,7 @@ static int i5400_init_csrows(struct mem_ctl_info *mci)
pvt = mci->pvt_info;
channel_count = pvt->maxch;
- max_csrows = pvt->maxdimmperch * 2;
+ max_csrows = pvt->maxdimmperch;
empty = 1; /* Assume NO memory */
@@ -1215,28 +1210,6 @@ static void i5400_enable_error_reporting(struct mem_ctl_info *mci)
}
/*
- * i5400_get_dimm_and_channel_counts(pdev, &num_csrows, &num_channels)
- *
- * ask the device how many channels are present and how many CSROWS
- * as well
- */
-static void i5400_get_dimm_and_channel_counts(struct pci_dev *pdev,
- int *num_dimms_per_channel,
- int *num_channels)
-{
- u8 value;
-
- /* Need to retrieve just how many channels and dimms per channel are
- * supported on this memory controller
- */
- pci_read_config_byte(pdev, MAXDIMMPERCH, &value);
- *num_dimms_per_channel = (int)value * 2;
-
- pci_read_config_byte(pdev, MAXCH, &value);
- *num_channels = (int)value;
-}
-
-/*
* i5400_probe1 Probe for ONE instance of device to see if it is
* present.
* return:
@@ -1263,22 +1236,16 @@ static int i5400_probe1(struct pci_dev *pdev, int dev_idx)
if (PCI_FUNC(pdev->devfn) != 0)
return -ENODEV;
- /* Ask the devices for the number of CSROWS and CHANNELS so
- * that we can calculate the memory resources, etc
- *
- * The Chipset will report what it can handle which will be greater
- * or equal to what the motherboard manufacturer will implement.
- *
- * As we don't have a motherboard identification routine to determine
+ /* As we don't have a motherboard identification routine to determine
* actual number of slots/dimms per channel, we thus utilize the
* resource as specified by the chipset. Thus, we might have
* have more DIMMs per channel than actually on the mobo, but this
* allows the driver to support upto the chipset max, without
* some fancy mobo determination.
*/
- i5400_get_dimm_and_channel_counts(pdev, &num_dimms_per_channel,
- &num_channels);
- num_csrows = num_dimms_per_channel * 2;
+ num_dimms_per_channel = MAX_DIMMS_PER_CHANNEL;
+ num_channels = MAX_CHANNELS;
+ num_csrows = num_dimms_per_channel;
debugf0("MC: %s(): Number of - Channels= %d DIMMS= %d CSROWS= %d\n",
__func__, num_channels, num_dimms_per_channel, num_csrows);