i7core_edac: scrubbing fixups
Get a more reliable DCLK value from DMI, name the SCRUBINTERVAL mask
and guard against potential overflow in the scrub rate computations.
Signed-off-by: Nils Carlson <nils.carlson@ericsson.com>
diff --git a/drivers/edac/i7core_edac.c b/drivers/edac/i7core_edac.c
index 6ae7795..7cb68de 100644
--- a/drivers/edac/i7core_edac.c
+++ b/drivers/edac/i7core_edac.c
@@ -31,6 +31,7 @@
#include <linux/pci_ids.h>
#include <linux/slab.h>
#include <linux/delay.h>
+#include <linux/dmi.h>
#include <linux/edac.h>
#include <linux/mmzone.h>
#include <linux/smp.h>
@@ -107,6 +108,7 @@
#define MC_SCRUB_CONTROL 0x4c
#define STARTSCRUB (1 << 24)
+ #define SCRUBINTERVAL_MASK 0xffffff
#define MC_COR_ECC_CNT_0 0x80
#define MC_COR_ECC_CNT_1 0x84
@@ -275,6 +277,9 @@
/* Count indicator to show errors not got */
unsigned mce_overrun;
+ /* DCLK Frequency used for computing scrub rate */
+ int dclk_freq;
+
/* Struct to control EDAC polling */
struct edac_pci_ctl_info *i7core_pci;
};
@@ -1952,6 +1957,112 @@
.notifier_call = i7core_mce_check_error,
};
+struct memdev_dmi_entry {
+ u8 type;
+ u8 length;
+ u16 handle;
+ u16 phys_mem_array_handle;
+ u16 mem_err_info_handle;
+ u16 total_width;
+ u16 data_width;
+ u16 size;
+ u8 form;
+ u8 device_set;
+ u8 device_locator;
+ u8 bank_locator;
+ u8 memory_type;
+ u16 type_detail;
+ u16 speed;
+ u8 manufacturer;
+ u8 serial_number;
+ u8 asset_tag;
+ u8 part_number;
+ u8 attributes;
+ u32 extended_size;
+ u16 conf_mem_clk_speed;
+} __attribute__((__packed__));
+
+
+/*
+ * Decode the DRAM Clock Frequency, be paranoid, make sure that all
+ * memory devices show the same speed, and if they don't then consider
+ * all speeds to be invalid.
+ */
+static void decode_dclk(const struct dmi_header *dh, void *_dclk_freq)
+{
+ int *dclk_freq = _dclk_freq;
+ u16 dmi_mem_clk_speed;
+
+ if (*dclk_freq == -1)
+ return;
+
+ if (dh->type == DMI_ENTRY_MEM_DEVICE) {
+ struct memdev_dmi_entry *memdev_dmi_entry =
+ (struct memdev_dmi_entry *)dh;
+ unsigned long conf_mem_clk_speed_offset =
+ (unsigned long)&memdev_dmi_entry->conf_mem_clk_speed -
+ (unsigned long)&memdev_dmi_entry->type;
+ unsigned long speed_offset =
+ (unsigned long)&memdev_dmi_entry->speed -
+ (unsigned long)&memdev_dmi_entry->type;
+
+ /* Check that a DIMM is present */
+ if (memdev_dmi_entry->size == 0)
+ return;
+
+ /*
+ * Pick the configured speed if it's available, otherwise
+ * pick the DIMM speed, or we don't have a speed.
+ */
+ if (memdev_dmi_entry->length > conf_mem_clk_speed_offset) {
+ dmi_mem_clk_speed =
+ memdev_dmi_entry->conf_mem_clk_speed;
+ } else if (memdev_dmi_entry->length > speed_offset) {
+ dmi_mem_clk_speed = memdev_dmi_entry->speed;
+ } else {
+ *dclk_freq = -1;
+ return;
+ }
+
+ if (*dclk_freq == 0) {
+ /* First pass, speed was 0 */
+ if (dmi_mem_clk_speed > 0) {
+ /* Set speed if a valid speed is read */
+ *dclk_freq = dmi_mem_clk_speed;
+ } else {
+ /* Otherwise we don't have a valid speed */
+ *dclk_freq = -1;
+ }
+ } else if (*dclk_freq > 0 &&
+ *dclk_freq != dmi_mem_clk_speed) {
+ /*
+ * If we have a speed, check that all DIMMS are the same
+ * speed, otherwise set the speed as invalid.
+ */
+ *dclk_freq = -1;
+ }
+ }
+}
+
+/*
+ * The default DCLK frequency is used as a fallback if we
+ * fail to find anything reliable in the DMI. The value
+ * is taken straight from the datasheet.
+ */
+#define DEFAULT_DCLK_FREQ 800
+
+static int get_dclk_freq(void)
+{
+ int dclk_freq = 0;
+
+ dmi_walk(decode_dclk, (void *)&dclk_freq);
+
+ if (dclk_freq < 1)
+ return DEFAULT_DCLK_FREQ;
+
+ return dclk_freq;
+}
+
/*
* set_sdram_scrub_rate This routine sets byte/sec bandwidth scrub rate
* to hardware according to SCRUBINTERVAL formula
@@ -1961,8 +2072,6 @@
{
struct i7core_pvt *pvt = mci->pvt_info;
struct pci_dev *pdev;
- const u32 cache_line_size = 64;
- const u32 freq_dclk = 800*1000000;
u32 dw_scrub;
u32 dw_ssr;
@@ -1977,18 +2086,28 @@
/* Prepare to disable petrol scrub */
dw_scrub &= ~STARTSCRUB;
/* Stop the patrol scrub engine */
- write_and_test(pdev, MC_SCRUB_CONTROL, dw_scrub & ~0x00ffffff);
+ write_and_test(pdev, MC_SCRUB_CONTROL,
+ dw_scrub & ~SCRUBINTERVAL_MASK);
/* Get current status of scrub rate and set bit to disable */
pci_read_config_dword(pdev, MC_SSRCONTROL, &dw_ssr);
dw_ssr &= ~SSR_MODE_MASK;
dw_ssr |= SSR_MODE_DISABLE;
} else {
+ const int cache_line_size = 64;
+ const u32 freq_dclk_mhz = pvt->dclk_freq;
+ unsigned long long scrub_interval;
/*
* Translate the desired scrub rate to a register value and
- * program the cooresponding register value.
+ * program the corresponding register value.
*/
- dw_scrub = 0x00ffffff & (cache_line_size * freq_dclk / new_bw);
+ scrub_interval = (unsigned long long)freq_dclk_mhz *
+ cache_line_size * 1000000 / new_bw;
+
+ if (!scrub_interval || scrub_interval > SCRUBINTERVAL_MASK)
+ return -EINVAL;
+
+ dw_scrub = SCRUBINTERVAL_MASK & scrub_interval;
/* Start the patrol scrub engine */
pci_write_config_dword(pdev, MC_SCRUB_CONTROL,
@@ -2015,7 +2134,8 @@
struct i7core_pvt *pvt = mci->pvt_info;
struct pci_dev *pdev;
const u32 cache_line_size = 64;
- const u32 freq_dclk = 800*1000000;
+ const u32 freq_dclk_mhz = pvt->dclk_freq;
+ unsigned long long scrub_rate;
u32 scrubval;
/* Get data from the MC register, function 2 */
@@ -2027,12 +2147,14 @@
pci_read_config_dword(pdev, MC_SCRUB_CONTROL, &scrubval);
/* Mask highest 8-bits to 0 */
- scrubval &= 0x00ffffff;
+ scrubval &= SCRUBINTERVAL_MASK;
if (!scrubval)
return 0;
/* Calculate scrub rate value into byte/sec bandwidth */
- return 0xffffffff & (cache_line_size * freq_dclk / (u64) scrubval);
+ scrub_rate = (unsigned long long)freq_dclk_mhz *
+ 1000000 * cache_line_size / scrubval;
+ return (int)scrub_rate;
}
static void enable_sdram_scrub_setting(struct mem_ctl_info *mci)
@@ -2204,6 +2326,9 @@
/* allocating generic PCI control info */
i7core_pci_ctl_create(pvt);
+ /* DCLK for scrub rate setting */
+ pvt->dclk_freq = get_dclk_freq();
+
atomic_notifier_chain_register(&x86_mce_decoder_chain, &i7_mce_dec);
return 0;