/*
 * AMD 76x Memory Controller kernel module
 * (C) 2003 Linux Networx (http://lnxi.com)
 * This file may be distributed under the terms of the
 * GNU General Public License.
 *
 * Written by Thayne Harbaugh
 * Based on work by Dan Hollis <goemon at anime dot net> and others.
 *      http://www.anime.net/~goemon/linux-ecc/
 *
 * $Id: edac_amd76x.c,v 1.4.2.5 2005/10/05 00:43:44 dsp_llnl Exp $
 *
 */

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

#define EDAC_MOD_STR    "amd76x_edac"

#define amd76x_printk(level, fmt, arg...) \
        edac_printk(level, "amd76x", fmt, ##arg)

#define amd76x_mc_printk(mci, level, fmt, arg...) \
        edac_mc_chipset_printk(mci, level, "amd76x", fmt, ##arg)

#define AMD76X_NR_CSROWS 8
#define AMD76X_NR_DIMMS  4

/* AMD 76x register addresses - device 0 function 0 - PCI bridge */

#define AMD76X_ECC_MODE_STATUS  0x48    /* Mode and status of ECC (32b)
                                         *
                                         * 31:16 reserved
                                         * 15:14 SERR enabled: x1=ue 1x=ce
                                         * 13    reserved
                                         * 12    diag: disabled, enabled
                                         * 11:10 mode: dis, EC, ECC, ECC+scrub
                                         *  9:8  status: x1=ue 1x=ce
                                         *  7:4  UE cs row
                                         *  3:0  CE cs row
                                         */

#define AMD76X_DRAM_MODE_STATUS 0x58    /* DRAM Mode and status (32b)
                                         *
                                         * 31:26 clock disable 5 - 0
                                         * 25    SDRAM init
                                         * 24    reserved
                                         * 23    mode register service
                                         * 22:21 suspend to RAM
                                         * 20    burst refresh enable
                                         * 19    refresh disable
                                         * 18    reserved
                                         * 17:16 cycles-per-refresh
                                         * 15:8  reserved
                                         *  7:0  x4 mode enable 7 - 0
                                         */

#define AMD76X_MEM_BASE_ADDR    0xC0    /* Memory base address (8 x 32b)
                                         *
                                         * 31:23 chip-select base
                                         * 22:16 reserved
                                         * 15:7  chip-select mask
                                         *  6:3  reserved
                                         *  2:1  address mode
                                         *  0    chip-select enable
                                         */

struct amd76x_error_info {
        u32 ecc_mode_status;
};

enum amd76x_chips {
        AMD761 = 0,
        AMD762
};

struct amd76x_dev_info {
        const char *ctl_name;
};

static const struct amd76x_dev_info amd76x_devs[] = {
        [AMD761] = {
                .ctl_name = "AMD761"},
        [AMD762] = {
                .ctl_name = "AMD762"},
};

static struct edac_pci_ctl_info *amd76x_pci;

/**
 *      amd76x_get_error_info   -       fetch error information
 *      @mci: Memory controller
 *      @info: Info to fill in
 *
 *      Fetch and store the AMD76x ECC status. Clear pending status
 *      on the chip so that further errors will be reported
 */
static void amd76x_get_error_info(struct mem_ctl_info *mci,
                                struct amd76x_error_info *info)
{
        struct pci_dev *pdev;

        pdev = to_pci_dev(mci->pdev);
        pci_read_config_dword(pdev, AMD76X_ECC_MODE_STATUS,
                        &info->ecc_mode_status);

        if (info->ecc_mode_status & BIT(8))
                pci_write_bits32(pdev, AMD76X_ECC_MODE_STATUS,
                                 (u32) BIT(8), (u32) BIT(8));

        if (info->ecc_mode_status & BIT(9))
                pci_write_bits32(pdev, AMD76X_ECC_MODE_STATUS,
                                 (u32) BIT(9), (u32) BIT(9));
}

/**
 *      amd76x_process_error_info       -       Error check
 *      @mci: Memory controller
 *      @info: Previously fetched information from chip
 *      @handle_errors: 1 if we should do recovery
 *
 *      Process the chip state and decide if an error has occurred.
 *      A return of 1 indicates an error. Also if handle_errors is true
 *      then attempt to handle and clean up after the error
 */
static int amd76x_process_error_info(struct mem_ctl_info *mci,
                                struct amd76x_error_info *info,
                                int handle_errors)
{
        int error_found;
        u32 row;

        error_found = 0;

        /*
         *      Check for an uncorrectable error
         */
        if (info->ecc_mode_status & BIT(8)) {
                error_found = 1;

                if (handle_errors) {
                        row = (info->ecc_mode_status >> 4) & 0xf;
                        edac_mc_handle_error(HW_EVENT_ERR_UNCORRECTED, mci, 1,
                                             mci->csrows[row]->first_page, 0, 0,
                                             row, 0, -1,
                                             mci->ctl_name, "");
                }
        }

        /*
         *      Check for a correctable error
         */
        if (info->ecc_mode_status & BIT(9)) {
                error_found = 1;

                if (handle_errors) {
                        row = info->ecc_mode_status & 0xf;
                        edac_mc_handle_error(HW_EVENT_ERR_CORRECTED, mci, 1,
                                             mci->csrows[row]->first_page, 0, 0,
                                             row, 0, -1,
                                             mci->ctl_name, "");
                }
        }

        return error_found;
}

/**
 *      amd76x_check    -       Poll the controller
 *      @mci: Memory controller
 *
 *      Called by the poll handlers this function reads the status
 *      from the controller and checks for errors.
 */
static void amd76x_check(struct mem_ctl_info *mci)
{
        struct amd76x_error_info info;
        amd76x_get_error_info(mci, &info);
        amd76x_process_error_info(mci, &info, 1);
}

static void amd76x_init_csrows(struct mem_ctl_info *mci, struct pci_dev *pdev,
                        enum edac_type edac_mode)
{
        struct csrow_info *csrow;
        struct dimm_info *dimm;
        u32 mba, mba_base, mba_mask, dms;
        int index;

        for (index = 0; index < mci->nr_csrows; index++) {
                csrow = mci->csrows[index];
                dimm = csrow->channels[0]->dimm;

                /* find the DRAM Chip Select Base address and mask */
                pci_read_config_dword(pdev,
                                AMD76X_MEM_BASE_ADDR + (index * 4), &mba);

                if (!(mba & BIT(0)))
                        continue;

                mba_base = mba & 0xff800000UL;
                mba_mask = ((mba & 0xff80) << 16) | 0x7fffffUL;
                pci_read_config_dword(pdev, AMD76X_DRAM_MODE_STATUS, &dms);
                csrow->first_page = mba_base >> PAGE_SHIFT;
                dimm->nr_pages = (mba_mask + 1) >> PAGE_SHIFT;
                csrow->last_page = csrow->first_page + dimm->nr_pages - 1;
                csrow->page_mask = mba_mask >> PAGE_SHIFT;
                dimm->grain = dimm->nr_pages << PAGE_SHIFT;
                dimm->mtype = MEM_RDDR;
                dimm->dtype = ((dms >> index) & 0x1) ? DEV_X4 : DEV_UNKNOWN;
                dimm->edac_mode = edac_mode;
        }
}

/**
 *      amd76x_probe1   -       Perform set up for detected device
 *      @pdev; PCI device detected
 *      @dev_idx: Device type index
 *
 *      We have found an AMD76x and now need to set up the memory
 *      controller status reporting. We configure and set up the
 *      memory controller reporting and claim the device.
 */
static int amd76x_probe1(struct pci_dev *pdev, int dev_idx)
{
        static const enum edac_type ems_modes[] = {
                EDAC_NONE,
                EDAC_EC,
                EDAC_SECDED,
                EDAC_SECDED
        };
        struct mem_ctl_info *mci;
        struct edac_mc_layer layers[2];
        u32 ems;
        u32 ems_mode;
        struct amd76x_error_info discard;

        edac_dbg(0, "\n");
        pci_read_config_dword(pdev, AMD76X_ECC_MODE_STATUS, &ems);
        ems_mode = (ems >> 10) & 0x3;

        layers[0].type = EDAC_MC_LAYER_CHIP_SELECT;
        layers[0].size = AMD76X_NR_CSROWS;
        layers[0].is_virt_csrow = true;
        layers[1].type = EDAC_MC_LAYER_CHANNEL;
        layers[1].size = 1;
        layers[1].is_virt_csrow = false;
        mci = edac_mc_alloc(0, ARRAY_SIZE(layers), layers, 0);

        if (mci == NULL)
                return -ENOMEM;

        edac_dbg(0, "mci = %p\n", mci);
        mci->pdev = &pdev->dev;
        mci->mtype_cap = MEM_FLAG_RDDR;
        mci->edac_ctl_cap = EDAC_FLAG_NONE | EDAC_FLAG_EC | EDAC_FLAG_SECDED;
        mci->edac_cap = ems_mode ?
                (EDAC_FLAG_EC | EDAC_FLAG_SECDED) : EDAC_FLAG_NONE;
        mci->mod_name = EDAC_MOD_STR;
        mci->ctl_name = amd76x_devs[dev_idx].ctl_name;
        mci->dev_name = pci_name(pdev);
        mci->edac_check = amd76x_check;
        mci->ctl_page_to_phys = NULL;

        amd76x_init_csrows(mci, pdev, ems_modes[ems_mode]);
        amd76x_get_error_info(mci, &discard);   /* clear counters */

        /* Here we assume that we will never see multiple instances of this
         * type of memory controller.  The ID is therefore hardcoded to 0.
         */
        if (edac_mc_add_mc(mci)) {
                edac_dbg(3, "failed edac_mc_add_mc()\n");
                goto fail;
        }

        /* allocating generic PCI control info */
        amd76x_pci = edac_pci_create_generic_ctl(&pdev->dev, EDAC_MOD_STR);
        if (!amd76x_pci) {
                printk(KERN_WARNING
                        "%s(): Unable to create PCI control\n",
                        __func__);
                printk(KERN_WARNING
                        "%s(): PCI error report via EDAC not setup\n",
                        __func__);
        }

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

fail:
        edac_mc_free(mci);
        return -ENODEV;
}

/* returns count (>= 0), or negative on error */
static int amd76x_init_one(struct pci_dev *pdev,
                           const struct pci_device_id *ent)
{
        edac_dbg(0, "\n");

        /* don't need to call pci_enable_device() */
        return amd76x_probe1(pdev, ent->driver_data);
}

/**
 *      amd76x_remove_one       -       driver shutdown
 *      @pdev: PCI device being handed back
 *
 *      Called when the driver is unloaded. Find the matching mci
 *      structure for the device then delete the mci and free the
 *      resources.
 */
static void amd76x_remove_one(struct pci_dev *pdev)
{
        struct mem_ctl_info *mci;

        edac_dbg(0, "\n");

        if (amd76x_pci)
                edac_pci_release_generic_ctl(amd76x_pci);

        if ((mci = edac_mc_del_mc(&pdev->dev)) == NULL)
                return;

        edac_mc_free(mci);
}

static const struct pci_device_id amd76x_pci_tbl[] = {
        {
         PCI_VEND_DEV(AMD, FE_GATE_700C), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
         AMD762},
        {
         PCI_VEND_DEV(AMD, FE_GATE_700E), PCI_ANY_ID, PCI_ANY_ID, 0, 0,
         AMD761},
        {
         0,
         }                      /* 0 terminated list. */
};

MODULE_DEVICE_TABLE(pci, amd76x_pci_tbl);

static struct pci_driver amd76x_driver = {
        .name = EDAC_MOD_STR,
        .probe = amd76x_init_one,
        .remove = amd76x_remove_one,
        .id_table = amd76x_pci_tbl,
};

static int __init amd76x_init(void)
{
       /* Ensure that the OPSTATE is set correctly for POLL or NMI */
       opstate_init();

        return pci_register_driver(&amd76x_driver);
}

static void __exit amd76x_exit(void)
{
        pci_unregister_driver(&amd76x_driver);
}

module_init(amd76x_init);
module_exit(amd76x_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Linux Networx (http://lnxi.com) Thayne Harbaugh");
MODULE_DESCRIPTION("MC support for AMD 76x memory controllers");

module_param(edac_op_state, int, 0444);
MODULE_PARM_DESC(edac_op_state, "EDAC Error Reporting state: 0=Poll,1=NMI");