Date:	Wed, 5 Nov 2008 22:29:11 +0000
From:	Hitoshi Mitake <mitake@...stcom.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	dougthompson@...ssion.com, linux-kernel@...r.kernel.org,
	ktaka@...stcom.com
Subject: Re: [PATCH 1/1] edac x38: new MC driver module

On Mon, 20 Oct 2008 16:32:28 -0700
Andrew Morton <akpm@...ux-foundation.org> wrote:

> On Fri, 17 Oct 2008 15:39:45 -0600
> dougthompson@...ssion.com wrote:
> 
> > From: Hitoshi Mitake <mitake@...stcom.com>
> > 
> > I wrote a new module for Intel X38 chipset.
> > This chipset is very similar to Intel 3200 chipset,
> > but there are some different points,
> > so I copyed i3200_edac.c and modified.
> > 
> > This is a Intel's web page describing this chipset.
> > http://www.intel.com/Products/Desktop/Chipsets/X38/X38-overview.htm
> > 
> > I've tested this new module with broken memory,
> > and it seems working well.
> > 
> > This is a patch, please use.
> > Hitoshi
> > 
> > Signed-off-by: Hitoshi Mitake <mitake@...stcom.com>
> > Signed-off-by: Doug Thompson <dougthompson@...ssion.com>
> > ---
> > 
> > Index: linux-2.6.27/drivers/edac/Kconfig
> > ===================================================================
> > --- linux-2.6.27.orig/drivers/edac/Kconfig
> > +++ linux-2.6.27/drivers/edac/Kconfig
> > @@ -102,6 +102,13 @@ config EDAC_I3000
> >  	  Support for error detection and correction on the Intel
> >  	  3000 and 3010 server chipsets.
> >  
> > +config EDAC_X38
> > +	tristate "Intel X38"
> > +	depends on EDAC_MM_EDAC && PCI && X86
> > +	help
> > +	  Support for error detection and correction on the Intel
> > +	  X38 server chipsets.
> 
> Is this truly X86, or will this driver only ever be used on x86_64 kernels?

I didn't know readq() of x86_64, and missed the case
to use this driver on x86_64. Thank you.

I wrote new version of this driver and tested. It works well.
This is replacement for old version.
Or should I send diff of two versions?


Signed-off-by: Hitoshi Mitake <mitake@...stcom.com>
Signed-off-by: Doug Thompson <dougthompson@...ssion.com>
---

Index: linux-2.6.27/drivers/edac/Kconfig
===================================================================
--- linux-2.6.27.orig/drivers/edac/Kconfig	2008-10-31 01:37:28.000000000 +0900
+++ linux-2.6.27/drivers/edac/Kconfig	2008-10-31 01:37:46.000000000 +0900
@@ -102,6 +102,13 @@
 	  Support for error detection and correction on the Intel
 	  3000 and 3010 server chipsets.
 
+config EDAC_X38
+	tristate "Intel X38"
+	depends on EDAC_MM_EDAC && PCI && (X86 || X86_64)
+	help
+	  Support for error detection and correction on the Intel
+	  X38 server chipsets.
+
 config EDAC_I82860
 	tristate "Intel 82860"
 	depends on EDAC_MM_EDAC && PCI && X86_32
Index: linux-2.6.27/drivers/edac/Makefile
===================================================================
--- linux-2.6.27.orig/drivers/edac/Makefile	2008-10-31 01:37:31.000000000 +0900
+++ linux-2.6.27/drivers/edac/Makefile	2008-10-31 01:37:46.000000000 +0900
@@ -26,6 +26,7 @@
 obj-$(CONFIG_EDAC_I82875P)		+= i82875p_edac.o
 obj-$(CONFIG_EDAC_I82975X)		+= i82975x_edac.o
 obj-$(CONFIG_EDAC_I3000)		+= i3000_edac.o
+obj-$(CONFIG_EDAC_X38)			+= x38_edac.o
 obj-$(CONFIG_EDAC_I82860)		+= i82860_edac.o
 obj-$(CONFIG_EDAC_R82600)		+= r82600_edac.o
 obj-$(CONFIG_EDAC_PASEMI)		+= pasemi_edac.o
Index: linux-2.6.27/drivers/edac/x38_edac.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.27/drivers/edac/x38_edac.c	2008-10-31 01:37:46.000000000 +0900
@@ -0,0 +1,526 @@
+/*
+ * Intel X38 Memory Controller kernel module
+ * Copyright (C) 2008 Cluster Computing, Inc.
+ *
+ * This file may be distributed under the terms of the
+ * GNU General Public License.
+ *
+ * This file is based on i3200_edac.c
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/pci_ids.h>
+#include <linux/slab.h>
+#include <linux/edac.h>
+#include "edac_core.h"
+
+#define X38_REVISION		"1.1"
+
+#define EDAC_MOD_STR		"x38_edac"
+
+#define PCI_DEVICE_ID_INTEL_X38_HB	0x29e0
+
+#define X38_RANKS		8
+#define X38_RANKS_PER_CHANNEL	4
+#define X38_CHANNELS		2
+
+/* Intel X38 register addresses - device 0 function 0 - DRAM Controller */
+
+#define X38_MCHBAR_LOW	0x48	/* MCH Memory Mapped Register BAR */
+#define X38_MCHBAR_HIGH	0x4b
+#define X38_MCHBAR_MASK	0xfffffc000ULL	/* bits 35:14 */
+#define X38_MMR_WINDOW_SIZE	16384
+
+#define X38_TOM	0xa0	/* Top of Memory (16b)
+				 *
+				 * 15:10 reserved
+				 *  9:0  total populated physical memory
+				 */
+#define X38_TOM_MASK	0x3ff	/* bits 9:0 */
+#define X38_TOM_SHIFT 26	/* 64MiB grain */
+
+#define X38_ERRSTS	0xc8	/* 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 X38_ERRSTS_UE		0x0002
+#define X38_ERRSTS_CE		0x0001
+#define X38_ERRSTS_BITS	(X38_ERRSTS_UE | X38_ERRSTS_CE)
+
+
+/* Intel  MMIO register space - device 0 function 0 - MMR space */
+
+#define X38_C0DRB	0x200	/* Channel 0 DRAM Rank Boundary (16b x 4)
+				 *
+				 * 15:10 reserved
+				 *  9:0  Channel 0 DRAM Rank Boundary Address
+				 */
+#define X38_C1DRB	0x600	/* Channel 1 DRAM Rank Boundary (16b x 4) */
+#define X38_DRB_MASK	0x3ff	/* bits 9:0 */
+#define X38_DRB_SHIFT 26	/* 64MiB grain */
+
+#define X38_C0ECCERRLOG 0x280	/* 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 X38_C1ECCERRLOG 0x680	/* Channel 1 ECC Error Log (64b) */
+#define X38_ECCERRLOG_CE	0x1
+#define X38_ECCERRLOG_UE	0x2
+#define X38_ECCERRLOG_RANK_BITS	0x18000000
+#define X38_ECCERRLOG_SYNDROME_BITS	0xff0000
+
+#define X38_CAPID0 0xe0	/* see P.94 of spec for details */
+
+static int x38_channel_num;
+
+static int how_many_channel(struct pci_dev *pdev)
+{
+	unsigned char capid0_8b; /* 8th byte of CAPID0 */
+
+	pci_read_config_byte(pdev, X38_CAPID0 + 8, &capid0_8b);
+	if (capid0_8b & 0x20) {	/* check DCD: Dual Channel Disable */
+		debugf0("In single channel mode.\n");
+		x38_channel_num = 1;
+	} else {
+		debugf0("In dual channel mode.\n");
+		x38_channel_num = 2;
+	}
+
+	return x38_channel_num;
+}
+
+static unsigned long eccerrlog_syndrome(u64 log)
+{
+	return (log & X38_ECCERRLOG_SYNDROME_BITS) >> 16;
+}
+
+static int eccerrlog_row(int channel, u64 log)
+{
+	return ((log & X38_ECCERRLOG_RANK_BITS) >> 27) |
+		(channel * X38_RANKS_PER_CHANNEL);
+}
+
+enum x38_chips {
+	X38 = 0,
+};
+
+struct x38_dev_info {
+	const char *ctl_name;
+};
+
+struct x38_error_info {
+	u16 errsts;
+	u16 errsts2;
+	u64 eccerrlog[X38_CHANNELS];
+};
+
+static const struct x38_dev_info x38_devs[] = {
+	[X38] = {
+		.ctl_name = "x38"},
+};
+
+static struct pci_dev *mci_pdev;
+static int x38_registered = 1;
+
+
+static void x38_clear_error_info(struct mem_ctl_info *mci)
+{
+	struct pci_dev *pdev;
+
+	pdev = to_pci_dev(mci->dev);
+
+	/*
+	 * Clear any error bits.
+	 * (Yes, we really clear bits by writing 1 to them.)
+	 */
+	pci_write_bits16(pdev, X38_ERRSTS, X38_ERRSTS_BITS,
+			 X38_ERRSTS_BITS);
+}
+
+#ifndef CONFIG_X86_64
+static u64 readq(const void __iomem *addr)
+{
+	return readl(addr) | (((u64)readl(addr + 4)) << 32);
+}
+#endif	/* CONFIG_X86_64 */
+
+static void x38_get_and_clear_error_info(struct mem_ctl_info *mci,
+				 struct x38_error_info *info)
+{
+	struct pci_dev *pdev;
+	void __iomem *window = mci->pvt_info;
+
+	pdev = to_pci_dev(mci->dev);
+
+	/*
+	 * 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, X38_ERRSTS, &info->errsts);
+	if (!(info->errsts & X38_ERRSTS_BITS))
+		return;
+
+	info->eccerrlog[0] = readq(window + X38_C0ECCERRLOG);
+	if (x38_channel_num == 2)
+		info->eccerrlog[1] = readq(window + X38_C1ECCERRLOG);
+
+	pci_read_config_word(pdev, X38_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) & X38_ERRSTS_BITS) {
+		info->eccerrlog[0] = readq(window + X38_C0ECCERRLOG);
+		if (x38_channel_num == 2)
+			info->eccerrlog[1] =
+				readq(window + X38_C1ECCERRLOG);
+	}
+
+	x38_clear_error_info(mci);
+}
+
+static void x38_process_error_info(struct mem_ctl_info *mci,
+				struct x38_error_info *info)
+{
+	int channel;
+	u64 log;
+
+	if (!(info->errsts & X38_ERRSTS_BITS))
+		return;
+
+	if ((info->errsts ^ info->errsts2) & X38_ERRSTS_BITS) {
+		edac_mc_handle_ce_no_info(mci, "UE overwrote CE");
+		info->errsts = info->errsts2;
+	}
+
+	for (channel = 0; channel < x38_channel_num; channel++) {
+		log = info->eccerrlog[channel];
+		if (log & X38_ECCERRLOG_UE) {
+			edac_mc_handle_ue(mci, 0, 0,
+				eccerrlog_row(channel, log), "x38 UE");
+		} else if (log & X38_ECCERRLOG_CE) {
+			edac_mc_handle_ce(mci, 0, 0,
+				eccerrlog_syndrome(log),
+				eccerrlog_row(channel, log), 0, "x38 CE");
+		}
+	}
+}
+
+static void x38_check(struct mem_ctl_info *mci)
+{
+	struct x38_error_info info;
+
+	debugf1("MC%d: %s()\n", mci->mc_idx, __func__);
+	x38_get_and_clear_error_info(mci, &info);
+	x38_process_error_info(mci, &info);
+}
+
+
+void __iomem *x38_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, X38_MCHBAR_LOW, &u.mchbar_low);
+	pci_write_config_dword(pdev, X38_MCHBAR_LOW, u.mchbar_low | 0x1);
+	pci_read_config_dword(pdev, X38_MCHBAR_HIGH, &u.mchbar_high);
+	u.mchbar &= X38_MCHBAR_MASK;
+
+	if (u.mchbar != (resource_size_t)u.mchbar) {
+		printk(KERN_ERR
+			"x38: mmio space beyond accessible range (0x%llx)\n",
+			(unsigned long long)u.mchbar);
+		return NULL;
+	}
+
+	window = ioremap_nocache(u.mchbar, X38_MMR_WINDOW_SIZE);
+	if (!window)
+		printk(KERN_ERR "x38: cannot map mmio space at 0x%llx\n",
+			(unsigned long long)u.mchbar);
+
+	return window;
+}
+
+
+static void x38_get_drbs(void __iomem *window,
+			u16 drbs[X38_CHANNELS][X38_RANKS_PER_CHANNEL])
+{
+	int i;
+
+	for (i = 0; i < X38_RANKS_PER_CHANNEL; i++) {
+		drbs[0][i] = readw(window + X38_C0DRB + 2*i) & X38_DRB_MASK;
+		drbs[1][i] = readw(window + X38_C1DRB + 2*i) & X38_DRB_MASK;
+	}
+}
+
+static bool x38_is_stacked(struct pci_dev *pdev,
+			u16 drbs[X38_CHANNELS][X38_RANKS_PER_CHANNEL])
+{
+	u16 tom;
+
+	pci_read_config_word(pdev, X38_TOM, &tom);
+	tom &= X38_TOM_MASK;
+
+	return drbs[X38_CHANNELS - 1][X38_RANKS_PER_CHANNEL - 1] == tom;
+}
+
+static unsigned long drb_to_nr_pages(
+			u16 drbs[X38_CHANNELS][X38_RANKS_PER_CHANNEL],
+			bool stacked, int channel, int rank)
+{
+	int n;
+
+	n = drbs[channel][rank];
+	if (rank > 0)
+		n -= drbs[channel][rank - 1];
+	if (stacked && (channel == 1) && drbs[channel][rank] ==
+				drbs[channel][X38_RANKS_PER_CHANNEL - 1]) {
+		n -= drbs[0][X38_RANKS_PER_CHANNEL - 1];
+	}
+
+	n <<= (X38_DRB_SHIFT - PAGE_SHIFT);
+	return n;
+}
+
+static int x38_probe1(struct pci_dev *pdev, int dev_idx)
+{
+	int rc;
+	int i;
+	struct mem_ctl_info *mci = NULL;
+	unsigned long last_page;
+	u16 drbs[X38_CHANNELS][X38_RANKS_PER_CHANNEL];
+	bool stacked;
+	void __iomem *window;
+
+	debugf0("MC: %s()\n", __func__);
+
+	window = x38_map_mchbar(pdev);
+	if (!window)
+		return -ENODEV;
+
+	x38_get_drbs(window, drbs);
+
+	how_many_channel(pdev);
+
+	/* FIXME: unconventional pvt_info usage */
+	mci = edac_mc_alloc(0, X38_RANKS, x38_channel_num, 0);
+	if (!mci)
+		return -ENOMEM;
+
+	debugf3("MC: %s(): init mci\n", __func__);
+
+	mci->dev = &pdev->dev;
+	mci->mtype_cap = MEM_FLAG_DDR2;
+
+	mci->edac_ctl_cap = EDAC_FLAG_SECDED;
+	mci->edac_cap = EDAC_FLAG_SECDED;
+
+	mci->mod_name = EDAC_MOD_STR;
+	mci->mod_ver = X38_REVISION;
+	mci->ctl_name = x38_devs[dev_idx].ctl_name;
+	mci->dev_name = pci_name(pdev);
+	mci->edac_check = x38_check;
+	mci->ctl_page_to_phys = NULL;
+	mci->pvt_info = window;
+
+	stacked = x38_is_stacked(pdev, drbs);
+
+	/*
+	 * 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.
+	 */
+	last_page = -1UL;
+	for (i = 0; i < mci->nr_csrows; i++) {
+		unsigned long nr_pages;
+		struct csrow_info *csrow = &mci->csrows[i];
+
+		nr_pages = drb_to_nr_pages(drbs, stacked,
+			i / X38_RANKS_PER_CHANNEL,
+			i % X38_RANKS_PER_CHANNEL);
+
+		if (nr_pages == 0) {
+			csrow->mtype = MEM_EMPTY;
+			continue;
+		}
+
+		csrow->first_page = last_page + 1;
+		last_page += nr_pages;
+		csrow->last_page = last_page;
+		csrow->nr_pages = nr_pages;
+
+		csrow->grain = nr_pages << PAGE_SHIFT;
+		csrow->mtype = MEM_DDR2;
+		csrow->dtype = DEV_UNKNOWN;
+		csrow->edac_mode = EDAC_UNKNOWN;
+	}
+
+	x38_clear_error_info(mci);
+
+	rc = -ENODEV;
+	if (edac_mc_add_mc(mci)) {
+		debugf3("MC: %s(): failed edac_mc_add_mc()\n", __func__);
+		goto fail;
+	}
+
+	/* get this far and it's successful */
+	debugf3("MC: %s(): success\n", __func__);
+	return 0;
+
+fail:
+	iounmap(window);
+	if (mci)
+		edac_mc_free(mci);
+
+	return rc;
+}
+
+static int __devinit x38_init_one(struct pci_dev *pdev,
+				const struct pci_device_id *ent)
+{
+	int rc;
+
+	debugf0("MC: %s()\n", __func__);
+
+	if (pci_enable_device(pdev) < 0)
+		return -EIO;
+
+	rc = x38_probe1(pdev, ent->driver_data);
+	if (!mci_pdev)
+		mci_pdev = pci_dev_get(pdev);
+
+	return rc;
+}
+
+static void __devexit x38_remove_one(struct pci_dev *pdev)
+{
+	struct mem_ctl_info *mci;
+
+	debugf0("%s()\n", __func__);
+
+	mci = edac_mc_del_mc(&pdev->dev);
+	if (!mci)
+		return;
+
+	iounmap(mci->pvt_info);
+
+	edac_mc_free(mci);
+}
+
+static const struct pci_device_id x38_pci_tbl[] __devinitdata = {
+	{
+	 PCI_VEND_DEV(INTEL, X38_HB), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
+	 X38},
+	{
+	 0,
+	 }			/* 0 terminated list. */
+};
+
+MODULE_DEVICE_TABLE(pci, x38_pci_tbl);
+
+static struct pci_driver x38_driver = {
+	.name = EDAC_MOD_STR,
+	.probe = x38_init_one,
+	.remove = __devexit_p(x38_remove_one),
+	.id_table = x38_pci_tbl,
+};
+
+static int __init x38_init(void)
+{
+	int pci_rc;
+
+	debugf3("MC: %s()\n", __func__);
+
+	/* Ensure that the OPSTATE is set correctly for POLL or NMI */
+	opstate_init();
+
+	pci_rc = pci_register_driver(&x38_driver);
+	if (pci_rc < 0)
+		goto fail0;
+
+	if (!mci_pdev) {
+		x38_registered = 0;
+		mci_pdev = pci_get_device(PCI_VENDOR_ID_INTEL,
+					PCI_DEVICE_ID_INTEL_X38_HB, NULL);
+		if (!mci_pdev) {
+			debugf0("x38 pci_get_device fail\n");
+			pci_rc = -ENODEV;
+			goto fail1;
+		}
+
+		pci_rc = x38_init_one(mci_pdev, x38_pci_tbl);
+		if (pci_rc < 0) {
+			debugf0("x38 init fail\n");
+			pci_rc = -ENODEV;
+			goto fail1;
+		}
+	}
+
+	return 0;
+
+fail1:
+	pci_unregister_driver(&x38_driver);
+
+fail0:
+	if (mci_pdev)
+		pci_dev_put(mci_pdev);
+
+	return pci_rc;
+}
+
+static void __exit x38_exit(void)
+{
+	debugf3("MC: %s()\n", __func__);
+
+	pci_unregister_driver(&x38_driver);
+	if (!x38_registered) {
+		x38_remove_one(mci_pdev);
+		pci_dev_put(mci_pdev);
+	}
+}
+
+module_init(x38_init);
+module_exit(x38_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Cluster Computing, Inc. Hitoshi Mitake");
+MODULE_DESCRIPTION("MC support for Intel X38 memory hub controllers");
+
+module_param(edac_op_state, int, 0444);
+MODULE_PARM_DESC(edac_op_state, "EDAC Error Reporting state: 0=Poll,1=NMI");
--
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