drivers/edac/ie31200_edac.c - kernel/common - Git at Google

 /*
  * Intel E3-1200
  * Copyright (C) 2014 Jason Baron <[email protected]>
  *
  * Support for the E3-1200 processor family. Heavily based on previous
  * Intel EDAC drivers.
  *
  * Since the DRAM controller is on the cpu chip, we can use its PCI device
  * id to identify these processors.
  *
  * PCI DRAM controller device ids (Taken from The PCI ID Repository - http://pci-ids.ucw.cz/)
  *
  * 0108: Xeon E3-1200 Processor Family DRAM Controller
  * 010c: Xeon E3-1200/2nd Generation Core Processor Family DRAM Controller
  * 0150: Xeon E3-1200 v2/3rd Gen Core processor DRAM Controller
  * 0158: Xeon E3-1200 v2/Ivy Bridge DRAM Controller
  * 015c: Xeon E3-1200 v2/3rd Gen Core processor DRAM Controller
  * 0c04: Xeon E3-1200 v3/4th Gen Core Processor DRAM Controller
  * 0c08: Xeon E3-1200 v3 Processor DRAM Controller
  * 1918: Xeon E3-1200 v5 Skylake Host Bridge/DRAM Registers
  *
  * Based on Intel specification:
  * http://www.intel.com/content/dam/www/public/us/en/documents/datasheets/xeon-e3-1200v3-vol-2-datasheet.pdf
  * http://www.intel.com/content/www/us/en/processors/xeon/xeon-e3-1200-family-vol-2-datasheet.html
  *
  * According to the above datasheet (p.16):
  * "
  * 6. Software must not access B0/D0/F0 32-bit memory-mapped registers with
  * requests that cross a DW boundary.
  * "
  *
  * Thus, we make use of the explicit: lo_hi_readq(), which breaks the readq into
  * 2 readl() calls. This restriction may be lifted in subsequent chip releases,
  * but lo_hi_readq() ensures that we are safe across all e3-1200 processors.
  */

 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/pci.h>
 #include <linux/pci_ids.h>
 #include <linux/edac.h>

 #include <linux/io-64-nonatomic-lo-hi.h>
 #include "edac_module.h"

 #define IE31200_REVISION "1.0"
 #define EDAC_MOD_STR "ie31200_edac"

 #define ie31200_printk(level, fmt, arg...) \
 	edac_printk(level, "ie31200", fmt, ##arg)

 #define PCI_DEVICE_ID_INTEL_IE31200_HB_1 0x0108
 #define PCI_DEVICE_ID_INTEL_IE31200_HB_2 0x010c
 #define PCI_DEVICE_ID_INTEL_IE31200_HB_3 0x0150
 #define PCI_DEVICE_ID_INTEL_IE31200_HB_4 0x0158
 #define PCI_DEVICE_ID_INTEL_IE31200_HB_5 0x015c
 #define PCI_DEVICE_ID_INTEL_IE31200_HB_6 0x0c04
 #define PCI_DEVICE_ID_INTEL_IE31200_HB_7 0x0c08
 #define PCI_DEVICE_ID_INTEL_IE31200_HB_8 0x1918

 #define IE31200_DIMMS			4
 #define IE31200_RANKS			8
 #define IE31200_RANKS_PER_CHANNEL	4
 #define IE31200_DIMMS_PER_CHANNEL	2
 #define IE31200_CHANNELS		2

 /* Intel IE31200 register addresses - device 0 function 0 - DRAM Controller */
 #define IE31200_MCHBAR_LOW		0x48
 #define IE31200_MCHBAR_HIGH		0x4c
 #define IE31200_MCHBAR_MASK		GENMASK_ULL(38, 15)
 #define IE31200_MMR_WINDOW_SIZE		BIT(15)

 /*
  * Error Status Register (16b)
  *
  * 15    reserved
  * 14    Isochronous TBWRR Run Behind FIFO Full
  *       (ITCV)
  * 13    Isochronous TBWRR Run Behind FIFO Put
  *       (ITSTV)
  * 12    reserved
  * 11    MCH Thermal Sensor Event
  *       for SMI/SCI/SERR (GTSE)
  * 10    reserved
  *  9    LOCK to non-DRAM Memory Flag (LCKF)
  *  8    reserved
  *  7    DRAM Throttle Flag (DTF)
  *  6:2  reserved
  *  1    Multi-bit DRAM ECC Error Flag (DMERR)
  *  0    Single-bit DRAM ECC Error Flag (DSERR)
  */
 #define IE31200_ERRSTS			0xc8
 #define IE31200_ERRSTS_UE		BIT(1)
 #define IE31200_ERRSTS_CE		BIT(0)
 #define IE31200_ERRSTS_BITS		(IE31200_ERRSTS_UE | IE31200_ERRSTS_CE)

 /*
  * Channel 0 ECC Error Log (64b)
  *
  * 63:48 Error Column Address (ERRCOL)
  * 47:32 Error Row Address (ERRROW)
  * 31:29 Error Bank Address (ERRBANK)
  * 28:27 Error Rank Address (ERRRANK)
  * 26:24 reserved
  * 23:16 Error Syndrome (ERRSYND)
  * 15: 2 reserved
  *    1  Multiple Bit Error Status (MERRSTS)
  *    0  Correctable Error Status (CERRSTS)
  */

 #define IE31200_C0ECCERRLOG			0x40c8
 #define IE31200_C1ECCERRLOG			0x44c8
 #define IE31200_C0ECCERRLOG_SKL			0x4048
 #define IE31200_C1ECCERRLOG_SKL			0x4448
 #define IE31200_ECCERRLOG_CE			BIT(0)
 #define IE31200_ECCERRLOG_UE			BIT(1)
 #define IE31200_ECCERRLOG_RANK_BITS		GENMASK_ULL(28, 27)
 #define IE31200_ECCERRLOG_RANK_SHIFT		27
 #define IE31200_ECCERRLOG_SYNDROME_BITS		GENMASK_ULL(23, 16)
 #define IE31200_ECCERRLOG_SYNDROME_SHIFT	16

 #define IE31200_ECCERRLOG_SYNDROME(log)		   \
 	((log & IE31200_ECCERRLOG_SYNDROME_BITS) >> \
 	 IE31200_ECCERRLOG_SYNDROME_SHIFT)

 #define IE31200_CAPID0			0xe4
 #define IE31200_CAPID0_PDCD		BIT(4)
 #define IE31200_CAPID0_DDPCD		BIT(6)
 #define IE31200_CAPID0_ECC		BIT(1)

 #define IE31200_MAD_DIMM_0_OFFSET		0x5004
 #define IE31200_MAD_DIMM_0_OFFSET_SKL		0x500C
 #define IE31200_MAD_DIMM_SIZE			GENMASK_ULL(7, 0)
 #define IE31200_MAD_DIMM_A_RANK			BIT(17)
 #define IE31200_MAD_DIMM_A_RANK_SHIFT		17
 #define IE31200_MAD_DIMM_A_RANK_SKL		BIT(10)
 #define IE31200_MAD_DIMM_A_RANK_SKL_SHIFT	10
 #define IE31200_MAD_DIMM_A_WIDTH		BIT(19)
 #define IE31200_MAD_DIMM_A_WIDTH_SHIFT		19
 #define IE31200_MAD_DIMM_A_WIDTH_SKL		GENMASK_ULL(9, 8)
 #define IE31200_MAD_DIMM_A_WIDTH_SKL_SHIFT	8

 /* Skylake reports 1GB increments, everything else is 256MB */
 #define IE31200_PAGES(n, skl)	\
 	(n << (28 + (2 * skl) - PAGE_SHIFT))

 static int nr_channels;

 struct ie31200_priv {
 	void __iomem *window;
 	void __iomem *c0errlog;
 	void __iomem *c1errlog;
 };

 enum ie31200_chips {
 	IE31200 = 0,
 };

 struct ie31200_dev_info {
 	const char *ctl_name;
 };

 struct ie31200_error_info {
 	u16 errsts;
 	u16 errsts2;
 	u64 eccerrlog[IE31200_CHANNELS];
 };

 static const struct ie31200_dev_info ie31200_devs[] = {
 	[IE31200] = {
 		.ctl_name = "IE31200"
 	},
 };

 struct dimm_data {
 	u8 size; /* in multiples of 256MB, except Skylake is 1GB */
 	u8 dual_rank : 1,
 	   x16_width : 2; /* 0 means x8 width */
 };

 static int how_many_channels(struct pci_dev *pdev)
 {
 	int n_channels;
 	unsigned char capid0_2b; /* 2nd byte of CAPID0 */

 	pci_read_config_byte(pdev, IE31200_CAPID0 + 1, &capid0_2b);

 	/* check PDCD: Dual Channel Disable */
 	if (capid0_2b & IE31200_CAPID0_PDCD) {
 		edac_dbg(0, "In single channel mode\n");
 		n_channels = 1;
 	} else {
 		edac_dbg(0, "In dual channel mode\n");
 		n_channels = 2;
 	}

 	/* check DDPCD - check if both channels are filled */
 	if (capid0_2b & IE31200_CAPID0_DDPCD)
 		edac_dbg(0, "2 DIMMS per channel disabled\n");
 	else
 		edac_dbg(0, "2 DIMMS per channel enabled\n");

 	return n_channels;
 }

 static bool ecc_capable(struct pci_dev *pdev)
 {
 	unsigned char capid0_4b; /* 4th byte of CAPID0 */

 	pci_read_config_byte(pdev, IE31200_CAPID0 + 3, &capid0_4b);
 	if (capid0_4b & IE31200_CAPID0_ECC)
 		return false;
 	return true;
 }

 static int eccerrlog_row(u64 log)
 {
 	return ((log & IE31200_ECCERRLOG_RANK_BITS) >>
 				IE31200_ECCERRLOG_RANK_SHIFT);
 }

 static void ie31200_clear_error_info(struct mem_ctl_info *mci)
 {
 	/*
 	 * Clear any error bits.
 	 * (Yes, we really clear bits by writing 1 to them.)
 	 */
 	pci_write_bits16(to_pci_dev(mci->pdev), IE31200_ERRSTS,
 			 IE31200_ERRSTS_BITS, IE31200_ERRSTS_BITS);
 }

 static void ie31200_get_and_clear_error_info(struct mem_ctl_info *mci,
 					     struct ie31200_error_info *info)
 {
 	struct pci_dev *pdev;
 	struct ie31200_priv *priv = mci->pvt_info;

 	pdev = to_pci_dev(mci->pdev);

 	/*
 	 * This is a mess because there is no atomic way to read all the
 	 * registers at once and the registers can transition from CE being
 	 * overwritten by UE.
 	 */
 	pci_read_config_word(pdev, IE31200_ERRSTS, &info->errsts);
 	if (!(info->errsts & IE31200_ERRSTS_BITS))
 		return;

 	info->eccerrlog[0] = lo_hi_readq(priv->c0errlog);
 	if (nr_channels == 2)
 		info->eccerrlog[1] = lo_hi_readq(priv->c1errlog);

 	pci_read_config_word(pdev, IE31200_ERRSTS, &info->errsts2);

 	/*
 	 * If the error is the same for both reads then the first set
 	 * of reads is valid.  If there is a change then there is a CE
 	 * with no info and the second set of reads is valid and
 	 * should be UE info.
 	 */
 	if ((info->errsts ^ info->errsts2) & IE31200_ERRSTS_BITS) {
 		info->eccerrlog[0] = lo_hi_readq(priv->c0errlog);
 		if (nr_channels == 2)
 			info->eccerrlog[1] =
 				lo_hi_readq(priv->c1errlog);
 	}

 	ie31200_clear_error_info(mci);
 }

 static void ie31200_process_error_info(struct mem_ctl_info *mci,
 				       struct ie31200_error_info *info)
 {
 	int channel;
 	u64 log;

 	if (!(info->errsts & IE31200_ERRSTS_BITS))
 		return;

 	if ((info->errsts ^ info->errsts2) & IE31200_ERRSTS_BITS) {
 		edac_mc_handle_error(HW_EVENT_ERR_UNCORRECTED, mci, 1, 0, 0, 0,
 				     -1, -1, -1, "UE overwrote CE", "");
 		info->errsts = info->errsts2;
 	}

 	for (channel = 0; channel < nr_channels; channel++) {
 		log = info->eccerrlog[channel];
 		if (log & IE31200_ECCERRLOG_UE) {
 			edac_mc_handle_error(HW_EVENT_ERR_UNCORRECTED, mci, 1,
 					     0, 0, 0,
 					     eccerrlog_row(log),
 					     channel, -1,
 					     "ie31200 UE", "");
 		} else if (log & IE31200_ECCERRLOG_CE) {
 			edac_mc_handle_error(HW_EVENT_ERR_CORRECTED, mci, 1,
 					     0, 0,
 					     IE31200_ECCERRLOG_SYNDROME(log),
 					     eccerrlog_row(log),
 					     channel, -1,
 					     "ie31200 CE", "");
 		}
 	}
 }

 static void ie31200_check(struct mem_ctl_info *mci)
 {
 	struct ie31200_error_info info;

 	edac_dbg(1, "MC%d\n", mci->mc_idx);
 	ie31200_get_and_clear_error_info(mci, &info);
 	ie31200_process_error_info(mci, &info);
 }

 static void __iomem *ie31200_map_mchbar(struct pci_dev *pdev)
 {
 	union {
 		u64 mchbar;
 		struct {
 			u32 mchbar_low;
 			u32 mchbar_high;
 		};
 	} u;
 	void __iomem *window;

 	pci_read_config_dword(pdev, IE31200_MCHBAR_LOW, &u.mchbar_low);
 	pci_read_config_dword(pdev, IE31200_MCHBAR_HIGH, &u.mchbar_high);
 	u.mchbar &= IE31200_MCHBAR_MASK;

 	if (u.mchbar != (resource_size_t)u.mchbar) {
 		ie31200_printk(KERN_ERR, "mmio space beyond accessible range (0x%llx)\n",
 			       (unsigned long long)u.mchbar);
 		return NULL;
 	}

 	window = ioremap_nocache(u.mchbar, IE31200_MMR_WINDOW_SIZE);
 	if (!window)
 		ie31200_printk(KERN_ERR, "Cannot map mmio space at 0x%llx\n",
 			       (unsigned long long)u.mchbar);

 	return window;
 }

 static void __skl_populate_dimm_info(struct dimm_data *dd, u32 addr_decode,
 				     int chan)
 {
 	dd->size = (addr_decode >> (chan << 4)) & IE31200_MAD_DIMM_SIZE;
 	dd->dual_rank = (addr_decode & (IE31200_MAD_DIMM_A_RANK_SKL << (chan << 4))) ? 1 : 0;
 	dd->x16_width = ((addr_decode & (IE31200_MAD_DIMM_A_WIDTH_SKL << (chan << 4))) >>
 				(IE31200_MAD_DIMM_A_WIDTH_SKL_SHIFT + (chan << 4)));
 }

 static void __populate_dimm_info(struct dimm_data *dd, u32 addr_decode,
 				 int chan)
 {
 	dd->size = (addr_decode >> (chan << 3)) & IE31200_MAD_DIMM_SIZE;
 	dd->dual_rank = (addr_decode & (IE31200_MAD_DIMM_A_RANK << chan)) ? 1 : 0;
 	dd->x16_width = (addr_decode & (IE31200_MAD_DIMM_A_WIDTH << chan)) ? 1 : 0;
 }

 static void populate_dimm_info(struct dimm_data *dd, u32 addr_decode, int chan,
 			       bool skl)
 {
 	if (skl)
 		__skl_populate_dimm_info(dd, addr_decode, chan);
 	else
 		__populate_dimm_info(dd, addr_decode, chan);
 }


 static int ie31200_probe1(struct pci_dev *pdev, int dev_idx)
 {
 	int i, j, ret;
 	struct mem_ctl_info *mci = NULL;
 	struct edac_mc_layer layers[2];
 	struct dimm_data dimm_info[IE31200_CHANNELS][IE31200_DIMMS_PER_CHANNEL];
 	void __iomem *window;
 	struct ie31200_priv *priv;
 	u32 addr_decode, mad_offset;
 	bool skl = (pdev->device == PCI_DEVICE_ID_INTEL_IE31200_HB_8);

 	edac_dbg(0, "MC:\n");

 	if (!ecc_capable(pdev)) {
 		ie31200_printk(KERN_INFO, "No ECC support\n");
 		return -ENODEV;
 	}

 	nr_channels = how_many_channels(pdev);
 	layers[0].type = EDAC_MC_LAYER_CHIP_SELECT;
 	layers[0].size = IE31200_DIMMS;
 	layers[0].is_virt_csrow = true;
 	layers[1].type = EDAC_MC_LAYER_CHANNEL;
 	layers[1].size = nr_channels;
 	layers[1].is_virt_csrow = false;
 	mci = edac_mc_alloc(0, ARRAY_SIZE(layers), layers,
 			    sizeof(struct ie31200_priv));
 	if (!mci)
 		return -ENOMEM;

 	window = ie31200_map_mchbar(pdev);
 	if (!window) {
 		ret = -ENODEV;
 		goto fail_free;
 	}

 	edac_dbg(3, "MC: init mci\n");
 	mci->pdev = &pdev->dev;
 	if (skl)
 		mci->mtype_cap = MEM_FLAG_DDR4;
 	else
 		mci->mtype_cap = MEM_FLAG_DDR3;
 	mci->edac_ctl_cap = EDAC_FLAG_SECDED;
 	mci->edac_cap = EDAC_FLAG_SECDED;
 	mci->mod_name = EDAC_MOD_STR;
 	mci->mod_ver = IE31200_REVISION;
 	mci->ctl_name = ie31200_devs[dev_idx].ctl_name;
 	mci->dev_name = pci_name(pdev);
 	mci->edac_check = ie31200_check;
 	mci->ctl_page_to_phys = NULL;
 	priv = mci->pvt_info;
 	priv->window = window;
 	if (skl) {
 		priv->c0errlog = window + IE31200_C0ECCERRLOG_SKL;
 		priv->c1errlog = window + IE31200_C1ECCERRLOG_SKL;
 		mad_offset = IE31200_MAD_DIMM_0_OFFSET_SKL;
 	} else {
 		priv->c0errlog = window + IE31200_C0ECCERRLOG;
 		priv->c1errlog = window + IE31200_C1ECCERRLOG;
 		mad_offset = IE31200_MAD_DIMM_0_OFFSET;
 	}

 	/* populate DIMM info */
 	for (i = 0; i < IE31200_CHANNELS; i++) {
 		addr_decode = readl(window + mad_offset +
 					(i * 4));
 		edac_dbg(0, "addr_decode: 0x%x\n", addr_decode);
 		for (j = 0; j < IE31200_DIMMS_PER_CHANNEL; j++) {
 			populate_dimm_info(&dimm_info[i][j], addr_decode, j,
 					   skl);
 			edac_dbg(0, "size: 0x%x, rank: %d, width: %d\n",
 				 dimm_info[i][j].size,
 				 dimm_info[i][j].dual_rank,
 				 dimm_info[i][j].x16_width);
 		}
 	}

 	/*
 	 * The dram rank boundary (DRB) reg values are boundary addresses
 	 * for each DRAM rank with a granularity of 64MB.  DRB regs are
 	 * cumulative; the last one will contain the total memory
 	 * contained in all ranks.
 	 */
 	for (i = 0; i < IE31200_DIMMS_PER_CHANNEL; i++) {
 		for (j = 0; j < IE31200_CHANNELS; j++) {
 			struct dimm_info *dimm;
 			unsigned long nr_pages;

 			nr_pages = IE31200_PAGES(dimm_info[j][i].size, skl);
 			if (nr_pages == 0)
 				continue;

 			if (dimm_info[j][i].dual_rank) {
 				nr_pages = nr_pages / 2;
 				dimm = EDAC_DIMM_PTR(mci->layers, mci->dimms,
 						     mci->n_layers, (i * 2) + 1,
 						     j, 0);
 				dimm->nr_pages = nr_pages;
 				edac_dbg(0, "set nr pages: 0x%lx\n", nr_pages);
 				dimm->grain = 8; /* just a guess */
 				if (skl)
 					dimm->mtype = MEM_DDR4;
 				else
 					dimm->mtype = MEM_DDR3;
 				dimm->dtype = DEV_UNKNOWN;
 				dimm->edac_mode = EDAC_UNKNOWN;
 			}
 			dimm = EDAC_DIMM_PTR(mci->layers, mci->dimms,
 					     mci->n_layers, i * 2, j, 0);
 			dimm->nr_pages = nr_pages;
 			edac_dbg(0, "set nr pages: 0x%lx\n", nr_pages);
 			dimm->grain = 8; /* same guess */
 			if (skl)
 				dimm->mtype = MEM_DDR4;
 			else
 				dimm->mtype = MEM_DDR3;
 			dimm->dtype = DEV_UNKNOWN;
 			dimm->edac_mode = EDAC_UNKNOWN;
 		}
 	}

 	ie31200_clear_error_info(mci);

 	if (edac_mc_add_mc(mci)) {
 		edac_dbg(3, "MC: failed edac_mc_add_mc()\n");
 		ret = -ENODEV;
 		goto fail_unmap;
 	}

 	/* get this far and it's successful */
 	edac_dbg(3, "MC: success\n");
 	return 0;

 fail_unmap:
 	iounmap(window);

 fail_free:
 	edac_mc_free(mci);

 	return ret;
 }

 static int ie31200_init_one(struct pci_dev *pdev,
 			    const struct pci_device_id *ent)
 {
 	edac_dbg(0, "MC:\n");

 	if (pci_enable_device(pdev) < 0)
 		return -EIO;

 	return ie31200_probe1(pdev, ent->driver_data);
 }

 static void ie31200_remove_one(struct pci_dev *pdev)
 {
 	struct mem_ctl_info *mci;
 	struct ie31200_priv *priv;

 	edac_dbg(0, "\n");
 	mci = edac_mc_del_mc(&pdev->dev);
 	if (!mci)
 		return;
 	priv = mci->pvt_info;
 	iounmap(priv->window);
 	edac_mc_free(mci);
 }

 static const struct pci_device_id ie31200_pci_tbl[] = {
 	{
 		PCI_VEND_DEV(INTEL, IE31200_HB_1), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
 		IE31200},
 	{
 		PCI_VEND_DEV(INTEL, IE31200_HB_2), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
 		IE31200},
 	{
 		PCI_VEND_DEV(INTEL, IE31200_HB_3), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
 		IE31200},
 	{
 		PCI_VEND_DEV(INTEL, IE31200_HB_4), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
 		IE31200},
 	{
 		PCI_VEND_DEV(INTEL, IE31200_HB_5), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
 		IE31200},
 	{
 		PCI_VEND_DEV(INTEL, IE31200_HB_6), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
 		IE31200},
 	{
 		PCI_VEND_DEV(INTEL, IE31200_HB_7), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
 		IE31200},
 	{
 		PCI_VEND_DEV(INTEL, IE31200_HB_8), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
 		IE31200},
 	{
 		0,
 	}            /* 0 terminated list. */
 };
 MODULE_DEVICE_TABLE(pci, ie31200_pci_tbl);

 static struct pci_driver ie31200_driver = {
 	.name = EDAC_MOD_STR,
 	.probe = ie31200_init_one,
 	.remove = ie31200_remove_one,
 	.id_table = ie31200_pci_tbl,
 };

 static int __init ie31200_init(void)
 {
 	edac_dbg(3, "MC:\n");
 	/* Ensure that the OPSTATE is set correctly for POLL or NMI */
 	opstate_init();

 	return pci_register_driver(&ie31200_driver);
 }

 static void __exit ie31200_exit(void)
 {
 	edac_dbg(3, "MC:\n");
 	pci_unregister_driver(&ie31200_driver);
 }

 module_init(ie31200_init);
 module_exit(ie31200_exit);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Jason Baron <[email protected]>");
 MODULE_DESCRIPTION("MC support for Intel Processor E31200 memory hub controllers");
	/*
	* Intel E3-1200
	* Copyright (C) 2014 Jason Baron <[email protected]>
	*
	* Support for the E3-1200 processor family. Heavily based on previous
	* Intel EDAC drivers.
	*
	* Since the DRAM controller is on the cpu chip, we can use its PCI device
	* id to identify these processors.
	*
	* PCI DRAM controller device ids (Taken from The PCI ID Repository - http://pci-ids.ucw.cz/)
	*
	* 0108: Xeon E3-1200 Processor Family DRAM Controller
	* 010c: Xeon E3-1200/2nd Generation Core Processor Family DRAM Controller
	* 0150: Xeon E3-1200 v2/3rd Gen Core processor DRAM Controller
	* 0158: Xeon E3-1200 v2/Ivy Bridge DRAM Controller
	* 015c: Xeon E3-1200 v2/3rd Gen Core processor DRAM Controller
	* 0c04: Xeon E3-1200 v3/4th Gen Core Processor DRAM Controller
	* 0c08: Xeon E3-1200 v3 Processor DRAM Controller
	* 1918: Xeon E3-1200 v5 Skylake Host Bridge/DRAM Registers
	*
	* Based on Intel specification:
	* http://www.intel.com/content/dam/www/public/us/en/documents/datasheets/xeon-e3-1200v3-vol-2-datasheet.pdf
	* http://www.intel.com/content/www/us/en/processors/xeon/xeon-e3-1200-family-vol-2-datasheet.html
	*
	* According to the above datasheet (p.16):
	* "
	* 6. Software must not access B0/D0/F0 32-bit memory-mapped registers with
	* requests that cross a DW boundary.
	* "
	*
	* Thus, we make use of the explicit: lo_hi_readq(), which breaks the readq into
	* 2 readl() calls. This restriction may be lifted in subsequent chip releases,
	* but lo_hi_readq() ensures that we are safe across all e3-1200 processors.
	*/

	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/pci.h>
	#include <linux/pci_ids.h>
	#include <linux/edac.h>

	#include <linux/io-64-nonatomic-lo-hi.h>
	#include "edac_module.h"

	#define IE31200_REVISION "1.0"
	#define EDAC_MOD_STR "ie31200_edac"

	#define ie31200_printk(level, fmt, arg...) \
	edac_printk(level, "ie31200", fmt, ##arg)

	#define PCI_DEVICE_ID_INTEL_IE31200_HB_1 0x0108
	#define PCI_DEVICE_ID_INTEL_IE31200_HB_2 0x010c
	#define PCI_DEVICE_ID_INTEL_IE31200_HB_3 0x0150
	#define PCI_DEVICE_ID_INTEL_IE31200_HB_4 0x0158
	#define PCI_DEVICE_ID_INTEL_IE31200_HB_5 0x015c
	#define PCI_DEVICE_ID_INTEL_IE31200_HB_6 0x0c04
	#define PCI_DEVICE_ID_INTEL_IE31200_HB_7 0x0c08
	#define PCI_DEVICE_ID_INTEL_IE31200_HB_8 0x1918

	#define IE31200_DIMMS 4
	#define IE31200_RANKS 8
	#define IE31200_RANKS_PER_CHANNEL 4
	#define IE31200_DIMMS_PER_CHANNEL 2
	#define IE31200_CHANNELS 2

	/* Intel IE31200 register addresses - device 0 function 0 - DRAM Controller */
	#define IE31200_MCHBAR_LOW 0x48
	#define IE31200_MCHBAR_HIGH 0x4c
	#define IE31200_MCHBAR_MASK GENMASK_ULL(38, 15)
	#define IE31200_MMR_WINDOW_SIZE BIT(15)

	/*
	* Error Status Register (16b)
	*
	* 15 reserved
	* 14 Isochronous TBWRR Run Behind FIFO Full
	* (ITCV)
	* 13 Isochronous TBWRR Run Behind FIFO Put
	* (ITSTV)
	* 12 reserved
	* 11 MCH Thermal Sensor Event
	* for SMI/SCI/SERR (GTSE)
	* 10 reserved
	* 9 LOCK to non-DRAM Memory Flag (LCKF)
	* 8 reserved
	* 7 DRAM Throttle Flag (DTF)
	* 6:2 reserved
	* 1 Multi-bit DRAM ECC Error Flag (DMERR)
	* 0 Single-bit DRAM ECC Error Flag (DSERR)
	*/
	#define IE31200_ERRSTS 0xc8
	#define IE31200_ERRSTS_UE BIT(1)
	#define IE31200_ERRSTS_CE BIT(0)
	#define IE31200_ERRSTS_BITS (IE31200_ERRSTS_UE \| IE31200_ERRSTS_CE)

	/*
	* Channel 0 ECC Error Log (64b)
	*
	* 63:48 Error Column Address (ERRCOL)
	* 47:32 Error Row Address (ERRROW)
	* 31:29 Error Bank Address (ERRBANK)
	* 28:27 Error Rank Address (ERRRANK)
	* 26:24 reserved
	* 23:16 Error Syndrome (ERRSYND)
	* 15: 2 reserved
	* 1 Multiple Bit Error Status (MERRSTS)
	* 0 Correctable Error Status (CERRSTS)
	*/

	#define IE31200_C0ECCERRLOG 0x40c8
	#define IE31200_C1ECCERRLOG 0x44c8
	#define IE31200_C0ECCERRLOG_SKL 0x4048
	#define IE31200_C1ECCERRLOG_SKL 0x4448
	#define IE31200_ECCERRLOG_CE BIT(0)
	#define IE31200_ECCERRLOG_UE BIT(1)
	#define IE31200_ECCERRLOG_RANK_BITS GENMASK_ULL(28, 27)
	#define IE31200_ECCERRLOG_RANK_SHIFT 27
	#define IE31200_ECCERRLOG_SYNDROME_BITS GENMASK_ULL(23, 16)
	#define IE31200_ECCERRLOG_SYNDROME_SHIFT 16

	#define IE31200_ECCERRLOG_SYNDROME(log) \
	((log & IE31200_ECCERRLOG_SYNDROME_BITS) >> \
	IE31200_ECCERRLOG_SYNDROME_SHIFT)

	#define IE31200_CAPID0 0xe4
	#define IE31200_CAPID0_PDCD BIT(4)
	#define IE31200_CAPID0_DDPCD BIT(6)
	#define IE31200_CAPID0_ECC BIT(1)

	#define IE31200_MAD_DIMM_0_OFFSET 0x5004
	#define IE31200_MAD_DIMM_0_OFFSET_SKL 0x500C
	#define IE31200_MAD_DIMM_SIZE GENMASK_ULL(7, 0)
	#define IE31200_MAD_DIMM_A_RANK BIT(17)
	#define IE31200_MAD_DIMM_A_RANK_SHIFT 17
	#define IE31200_MAD_DIMM_A_RANK_SKL BIT(10)
	#define IE31200_MAD_DIMM_A_RANK_SKL_SHIFT 10
	#define IE31200_MAD_DIMM_A_WIDTH BIT(19)
	#define IE31200_MAD_DIMM_A_WIDTH_SHIFT 19
	#define IE31200_MAD_DIMM_A_WIDTH_SKL GENMASK_ULL(9, 8)
	#define IE31200_MAD_DIMM_A_WIDTH_SKL_SHIFT 8

	/* Skylake reports 1GB increments, everything else is 256MB */
	#define IE31200_PAGES(n, skl) \
	(n << (28 + (2 * skl) - PAGE_SHIFT))

	static int nr_channels;

	struct ie31200_priv {
	void __iomem *window;
	void __iomem *c0errlog;
	void __iomem *c1errlog;
	};

	enum ie31200_chips {
	IE31200 = 0,
	};

	struct ie31200_dev_info {
	const char *ctl_name;
	};

	struct ie31200_error_info {
	u16 errsts;
	u16 errsts2;
	u64 eccerrlog[IE31200_CHANNELS];
	};

	static const struct ie31200_dev_info ie31200_devs[] = {
	[IE31200] = {
	.ctl_name = "IE31200"
	},
	};

	struct dimm_data {
	u8 size; /* in multiples of 256MB, except Skylake is 1GB */
	u8 dual_rank : 1,
	x16_width : 2; /* 0 means x8 width */
	};

	static int how_many_channels(struct pci_dev *pdev)
	{
	int n_channels;
	unsigned char capid0_2b; /* 2nd byte of CAPID0 */

	pci_read_config_byte(pdev, IE31200_CAPID0 + 1, &capid0_2b);

	/* check PDCD: Dual Channel Disable */
	if (capid0_2b & IE31200_CAPID0_PDCD) {
	edac_dbg(0, "In single channel mode\n");
	n_channels = 1;
	} else {
	edac_dbg(0, "In dual channel mode\n");
	n_channels = 2;
	}

	/* check DDPCD - check if both channels are filled */
	if (capid0_2b & IE31200_CAPID0_DDPCD)
	edac_dbg(0, "2 DIMMS per channel disabled\n");
	else
	edac_dbg(0, "2 DIMMS per channel enabled\n");

	return n_channels;
	}

	static bool ecc_capable(struct pci_dev *pdev)
	{
	unsigned char capid0_4b; /* 4th byte of CAPID0 */

	pci_read_config_byte(pdev, IE31200_CAPID0 + 3, &capid0_4b);
	if (capid0_4b & IE31200_CAPID0_ECC)
	return false;
	return true;
	}

	static int eccerrlog_row(u64 log)
	{
	return ((log & IE31200_ECCERRLOG_RANK_BITS) >>
	IE31200_ECCERRLOG_RANK_SHIFT);
	}

	static void ie31200_clear_error_info(struct mem_ctl_info *mci)
	{
	/*
	* Clear any error bits.
	* (Yes, we really clear bits by writing 1 to them.)
	*/
	pci_write_bits16(to_pci_dev(mci->pdev), IE31200_ERRSTS,
	IE31200_ERRSTS_BITS, IE31200_ERRSTS_BITS);
	}

	static void ie31200_get_and_clear_error_info(struct mem_ctl_info *mci,
	struct ie31200_error_info *info)
	{
	struct pci_dev *pdev;
	struct ie31200_priv *priv = mci->pvt_info;

	pdev = to_pci_dev(mci->pdev);

	/*
	* This is a mess because there is no atomic way to read all the
	* registers at once and the registers can transition from CE being
	* overwritten by UE.
	*/
	pci_read_config_word(pdev, IE31200_ERRSTS, &info->errsts);
	if (!(info->errsts & IE31200_ERRSTS_BITS))
	return;

	info->eccerrlog[0] = lo_hi_readq(priv->c0errlog);
	if (nr_channels == 2)
	info->eccerrlog[1] = lo_hi_readq(priv->c1errlog);

	pci_read_config_word(pdev, IE31200_ERRSTS, &info->errsts2);

	/*
	* If the error is the same for both reads then the first set
	* of reads is valid. If there is a change then there is a CE
	* with no info and the second set of reads is valid and
	* should be UE info.
	*/
	if ((info->errsts ^ info->errsts2) & IE31200_ERRSTS_BITS) {
	info->eccerrlog[0] = lo_hi_readq(priv->c0errlog);
	if (nr_channels == 2)
	info->eccerrlog[1] =
	lo_hi_readq(priv->c1errlog);
	}

	ie31200_clear_error_info(mci);
	}

	static void ie31200_process_error_info(struct mem_ctl_info *mci,
	struct ie31200_error_info *info)
	{
	int channel;
	u64 log;

	if (!(info->errsts & IE31200_ERRSTS_BITS))
	return;

	if ((info->errsts ^ info->errsts2) & IE31200_ERRSTS_BITS) {
	edac_mc_handle_error(HW_EVENT_ERR_UNCORRECTED, mci, 1, 0, 0, 0,
	-1, -1, -1, "UE overwrote CE", "");
	info->errsts = info->errsts2;
	}

	for (channel = 0; channel < nr_channels; channel++) {
	log = info->eccerrlog[channel];
	if (log & IE31200_ECCERRLOG_UE) {
	edac_mc_handle_error(HW_EVENT_ERR_UNCORRECTED, mci, 1,
	0, 0, 0,
	eccerrlog_row(log),
	channel, -1,
	"ie31200 UE", "");
	} else if (log & IE31200_ECCERRLOG_CE) {
	edac_mc_handle_error(HW_EVENT_ERR_CORRECTED, mci, 1,
	0, 0,
	IE31200_ECCERRLOG_SYNDROME(log),
	eccerrlog_row(log),
	channel, -1,
	"ie31200 CE", "");
	}
	}
	}

	static void ie31200_check(struct mem_ctl_info *mci)
	{
	struct ie31200_error_info info;

	edac_dbg(1, "MC%d\n", mci->mc_idx);
	ie31200_get_and_clear_error_info(mci, &info);
	ie31200_process_error_info(mci, &info);
	}

	static void __iomem ie31200_map_mchbar(struct pci_dev pdev)
	{
	union {
	u64 mchbar;
	struct {
	u32 mchbar_low;
	u32 mchbar_high;
	};
	} u;
	void __iomem *window;

	pci_read_config_dword(pdev, IE31200_MCHBAR_LOW, &u.mchbar_low);
	pci_read_config_dword(pdev, IE31200_MCHBAR_HIGH, &u.mchbar_high);
	u.mchbar &= IE31200_MCHBAR_MASK;

	if (u.mchbar != (resource_size_t)u.mchbar) {
	ie31200_printk(KERN_ERR, "mmio space beyond accessible range (0x%llx)\n",
	(unsigned long long)u.mchbar);
	return NULL;
	}

	window = ioremap_nocache(u.mchbar, IE31200_MMR_WINDOW_SIZE);
	if (!window)
	ie31200_printk(KERN_ERR, "Cannot map mmio space at 0x%llx\n",
	(unsigned long long)u.mchbar);

	return window;
	}

	static void __skl_populate_dimm_info(struct dimm_data *dd, u32 addr_decode,
	int chan)
	{
	dd->size = (addr_decode >> (chan << 4)) & IE31200_MAD_DIMM_SIZE;
	dd->dual_rank = (addr_decode & (IE31200_MAD_DIMM_A_RANK_SKL << (chan << 4))) ? 1 : 0;
	dd->x16_width = ((addr_decode & (IE31200_MAD_DIMM_A_WIDTH_SKL << (chan << 4))) >>
	(IE31200_MAD_DIMM_A_WIDTH_SKL_SHIFT + (chan << 4)));
	}

	static void __populate_dimm_info(struct dimm_data *dd, u32 addr_decode,
	int chan)
	{
	dd->size = (addr_decode >> (chan << 3)) & IE31200_MAD_DIMM_SIZE;
	dd->dual_rank = (addr_decode & (IE31200_MAD_DIMM_A_RANK << chan)) ? 1 : 0;
	dd->x16_width = (addr_decode & (IE31200_MAD_DIMM_A_WIDTH << chan)) ? 1 : 0;
	}

	static void populate_dimm_info(struct dimm_data *dd, u32 addr_decode, int chan,
	bool skl)
	{
	if (skl)
	__skl_populate_dimm_info(dd, addr_decode, chan);
	else
	__populate_dimm_info(dd, addr_decode, chan);
	}


	static int ie31200_probe1(struct pci_dev *pdev, int dev_idx)
	{
	int i, j, ret;
	struct mem_ctl_info *mci = NULL;
	struct edac_mc_layer layers[2];
	struct dimm_data dimm_info[IE31200_CHANNELS][IE31200_DIMMS_PER_CHANNEL];
	void __iomem *window;
	struct ie31200_priv *priv;
	u32 addr_decode, mad_offset;
	bool skl = (pdev->device == PCI_DEVICE_ID_INTEL_IE31200_HB_8);

	edac_dbg(0, "MC:\n");

	if (!ecc_capable(pdev)) {
	ie31200_printk(KERN_INFO, "No ECC support\n");
	return -ENODEV;
	}

	nr_channels = how_many_channels(pdev);
	layers[0].type = EDAC_MC_LAYER_CHIP_SELECT;
	layers[0].size = IE31200_DIMMS;
	layers[0].is_virt_csrow = true;
	layers[1].type = EDAC_MC_LAYER_CHANNEL;
	layers[1].size = nr_channels;
	layers[1].is_virt_csrow = false;
	mci = edac_mc_alloc(0, ARRAY_SIZE(layers), layers,
	sizeof(struct ie31200_priv));
	if (!mci)
	return -ENOMEM;

	window = ie31200_map_mchbar(pdev);
	if (!window) {
	ret = -ENODEV;
	goto fail_free;
	}

	edac_dbg(3, "MC: init mci\n");
	mci->pdev = &pdev->dev;
	if (skl)
	mci->mtype_cap = MEM_FLAG_DDR4;
	else
	mci->mtype_cap = MEM_FLAG_DDR3;
	mci->edac_ctl_cap = EDAC_FLAG_SECDED;
	mci->edac_cap = EDAC_FLAG_SECDED;
	mci->mod_name = EDAC_MOD_STR;
	mci->mod_ver = IE31200_REVISION;
	mci->ctl_name = ie31200_devs[dev_idx].ctl_name;
	mci->dev_name = pci_name(pdev);
	mci->edac_check = ie31200_check;
	mci->ctl_page_to_phys = NULL;
	priv = mci->pvt_info;
	priv->window = window;
	if (skl) {
	priv->c0errlog = window + IE31200_C0ECCERRLOG_SKL;
	priv->c1errlog = window + IE31200_C1ECCERRLOG_SKL;
	mad_offset = IE31200_MAD_DIMM_0_OFFSET_SKL;
	} else {
	priv->c0errlog = window + IE31200_C0ECCERRLOG;
	priv->c1errlog = window + IE31200_C1ECCERRLOG;
	mad_offset = IE31200_MAD_DIMM_0_OFFSET;
	}

	/* populate DIMM info */
	for (i = 0; i < IE31200_CHANNELS; i++) {
	addr_decode = readl(window + mad_offset +
	(i * 4));
	edac_dbg(0, "addr_decode: 0x%x\n", addr_decode);
	for (j = 0; j < IE31200_DIMMS_PER_CHANNEL; j++) {
	populate_dimm_info(&dimm_info[i][j], addr_decode, j,
	skl);
	edac_dbg(0, "size: 0x%x, rank: %d, width: %d\n",
	dimm_info[i][j].size,
	dimm_info[i][j].dual_rank,
	dimm_info[i][j].x16_width);
	}
	}

	/*
	* The dram rank boundary (DRB) reg values are boundary addresses
	* for each DRAM rank with a granularity of 64MB. DRB regs are
	* cumulative; the last one will contain the total memory
	* contained in all ranks.
	*/
	for (i = 0; i < IE31200_DIMMS_PER_CHANNEL; i++) {
	for (j = 0; j < IE31200_CHANNELS; j++) {
	struct dimm_info *dimm;
	unsigned long nr_pages;

	nr_pages = IE31200_PAGES(dimm_info[j][i].size, skl);
	if (nr_pages == 0)
	continue;

	if (dimm_info[j][i].dual_rank) {
	nr_pages = nr_pages / 2;
	dimm = EDAC_DIMM_PTR(mci->layers, mci->dimms,
	mci->n_layers, (i * 2) + 1,
	j, 0);
	dimm->nr_pages = nr_pages;
	edac_dbg(0, "set nr pages: 0x%lx\n", nr_pages);
	dimm->grain = 8; /* just a guess */
	if (skl)
	dimm->mtype = MEM_DDR4;
	else
	dimm->mtype = MEM_DDR3;
	dimm->dtype = DEV_UNKNOWN;
	dimm->edac_mode = EDAC_UNKNOWN;
	}
	dimm = EDAC_DIMM_PTR(mci->layers, mci->dimms,
	mci->n_layers, i * 2, j, 0);
	dimm->nr_pages = nr_pages;
	edac_dbg(0, "set nr pages: 0x%lx\n", nr_pages);
	dimm->grain = 8; /* same guess */
	if (skl)
	dimm->mtype = MEM_DDR4;
	else
	dimm->mtype = MEM_DDR3;
	dimm->dtype = DEV_UNKNOWN;
	dimm->edac_mode = EDAC_UNKNOWN;
	}
	}

	ie31200_clear_error_info(mci);

	if (edac_mc_add_mc(mci)) {
	edac_dbg(3, "MC: failed edac_mc_add_mc()\n");
	ret = -ENODEV;
	goto fail_unmap;
	}

	/* get this far and it's successful */
	edac_dbg(3, "MC: success\n");
	return 0;

	fail_unmap:
	iounmap(window);

	fail_free:
	edac_mc_free(mci);

	return ret;
	}

	static int ie31200_init_one(struct pci_dev *pdev,
	const struct pci_device_id *ent)
	{
	edac_dbg(0, "MC:\n");

	if (pci_enable_device(pdev) < 0)
	return -EIO;

	return ie31200_probe1(pdev, ent->driver_data);
	}

	static void ie31200_remove_one(struct pci_dev *pdev)
	{
	struct mem_ctl_info *mci;
	struct ie31200_priv *priv;

	edac_dbg(0, "\n");
	mci = edac_mc_del_mc(&pdev->dev);
	if (!mci)
	return;
	priv = mci->pvt_info;
	iounmap(priv->window);
	edac_mc_free(mci);
	}

	static const struct pci_device_id ie31200_pci_tbl[] = {
	{
	PCI_VEND_DEV(INTEL, IE31200_HB_1), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
	IE31200},
	{
	PCI_VEND_DEV(INTEL, IE31200_HB_2), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
	IE31200},
	{
	PCI_VEND_DEV(INTEL, IE31200_HB_3), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
	IE31200},
	{
	PCI_VEND_DEV(INTEL, IE31200_HB_4), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
	IE31200},
	{
	PCI_VEND_DEV(INTEL, IE31200_HB_5), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
	IE31200},
	{
	PCI_VEND_DEV(INTEL, IE31200_HB_6), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
	IE31200},
	{
	PCI_VEND_DEV(INTEL, IE31200_HB_7), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
	IE31200},
	{
	PCI_VEND_DEV(INTEL, IE31200_HB_8), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
	IE31200},
	{
	0,
	} /* 0 terminated list. */
	};
	MODULE_DEVICE_TABLE(pci, ie31200_pci_tbl);

	static struct pci_driver ie31200_driver = {
	.name = EDAC_MOD_STR,
	.probe = ie31200_init_one,
	.remove = ie31200_remove_one,
	.id_table = ie31200_pci_tbl,
	};

	static int __init ie31200_init(void)
	{
	edac_dbg(3, "MC:\n");
	/* Ensure that the OPSTATE is set correctly for POLL or NMI */
	opstate_init();

	return pci_register_driver(&ie31200_driver);
	}

	static void __exit ie31200_exit(void)
	{
	edac_dbg(3, "MC:\n");
	pci_unregister_driver(&ie31200_driver);
	}

	module_init(ie31200_init);
	module_exit(ie31200_exit);

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Jason Baron <[email protected]>");
	MODULE_DESCRIPTION("MC support for Intel Processor E31200 memory hub controllers");