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Commit 535e9c78 authored by Nils Carlson's avatar Nils Carlson Committed by Mauro Carvalho Chehab
Browse files

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: default avatarNils Carlson <nils.carlson@ericsson.com>
parent 168eb34d

drivers/edac/i7core_edac.c

+133 −8
Original line number Diff line number Diff line
@@ -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 @@ MODULE_PARM_DESC(use_pci_fixup, "Enable PCI fixup to seek for hidden devices"); 


#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 @@ struct i7core_pvt { 
	/* 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 @@ static struct notifier_block i7_mce_dec = { 
	.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 @@ static int set_sdram_scrub_rate(struct mem_ctl_info *mci, u32 new_bw) 
{

	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 @@ static int set_sdram_scrub_rate(struct mem_ctl_info *mci, u32 new_bw) 
		/* 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 @@ static int get_sdram_scrub_rate(struct mem_ctl_info *mci) 
	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 @@ static int get_sdram_scrub_rate(struct mem_ctl_info *mci) 
	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 @@ static int i7core_register_mci(struct i7core_dev *i7core_dev) 
	/* 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;