/**
 * IBM Accelerator Family 'GenWQE'
 *
 * (C) Copyright IBM Corp. 2013
 *
 * Author: Frank Haverkamp <haver@linux.vnet.ibm.com>
 * Author: Joerg-Stephan Vogt <jsvogt@de.ibm.com>
 * Author: Michael Jung <mijung@gmx.net>
 * Author: Michael Ruettger <michael@ibmra.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License (version 2 only)
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 */

/*
 * Miscelanous functionality used in the other GenWQE driver parts.
 */

#include <linux/kernel.h>
#include <linux/dma-mapping.h>
#include <linux/sched.h>
#include <linux/vmalloc.h>
#include <linux/page-flags.h>
#include <linux/scatterlist.h>
#include <linux/hugetlb.h>
#include <linux/iommu.h>
#include <linux/delay.h>
#include <linux/pci.h>
#include <linux/dma-mapping.h>
#include <linux/ctype.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <asm/pgtable.h>

#include "genwqe_driver.h"
#include "card_base.h"
#include "card_ddcb.h"

/**
 * __genwqe_writeq() - Write 64-bit register
 * @cd:         genwqe device descriptor
 * @byte_offs:  byte offset within BAR
 * @val:        64-bit value
 *
 * Return: 0 if success; < 0 if error
 */
int __genwqe_writeq(struct genwqe_dev *cd, u64 byte_offs, u64 val)
{
        struct pci_dev *pci_dev = cd->pci_dev;

        if (cd->err_inject & GENWQE_INJECT_HARDWARE_FAILURE)
                return -EIO;

        if (cd->mmio == NULL)
                return -EIO;

        if (pci_channel_offline(pci_dev))
                return -EIO;

        __raw_writeq((__force u64)cpu_to_be64(val), cd->mmio + byte_offs);
        return 0;
}

/**
 * __genwqe_readq() - Read 64-bit register
 * @cd:         genwqe device descriptor
 * @byte_offs:  offset within BAR
 *
 * Return: value from register
 */
u64 __genwqe_readq(struct genwqe_dev *cd, u64 byte_offs)
{
        if (cd->err_inject & GENWQE_INJECT_HARDWARE_FAILURE)
                return 0xffffffffffffffffull;

        if ((cd->err_inject & GENWQE_INJECT_GFIR_FATAL) &&
            (byte_offs == IO_SLC_CFGREG_GFIR))
                return 0x000000000000ffffull;

        if ((cd->err_inject & GENWQE_INJECT_GFIR_INFO) &&
            (byte_offs == IO_SLC_CFGREG_GFIR))
                return 0x00000000ffff0000ull;

        if (cd->mmio == NULL)
                return 0xffffffffffffffffull;

        return be64_to_cpu((__force __be64)__raw_readq(cd->mmio + byte_offs));
}

/**
 * __genwqe_writel() - Write 32-bit register
 * @cd:         genwqe device descriptor
 * @byte_offs:  byte offset within BAR
 * @val:        32-bit value
 *
 * Return: 0 if success; < 0 if error
 */
int __genwqe_writel(struct genwqe_dev *cd, u64 byte_offs, u32 val)
{
        struct pci_dev *pci_dev = cd->pci_dev;

        if (cd->err_inject & GENWQE_INJECT_HARDWARE_FAILURE)
                return -EIO;

        if (cd->mmio == NULL)
                return -EIO;

        if (pci_channel_offline(pci_dev))
                return -EIO;

        __raw_writel((__force u32)cpu_to_be32(val), cd->mmio + byte_offs);
        return 0;
}

/**
 * __genwqe_readl() - Read 32-bit register
 * @cd:         genwqe device descriptor
 * @byte_offs:  offset within BAR
 *
 * Return: Value from register
 */
u32 __genwqe_readl(struct genwqe_dev *cd, u64 byte_offs)
{
        if (cd->err_inject & GENWQE_INJECT_HARDWARE_FAILURE)
                return 0xffffffff;

        if (cd->mmio == NULL)
                return 0xffffffff;

        return be32_to_cpu((__force __be32)__raw_readl(cd->mmio + byte_offs));
}

/**
 * genwqe_read_app_id() - Extract app_id
 *
 * app_unitcfg need to be filled with valid data first
 */
int genwqe_read_app_id(struct genwqe_dev *cd, char *app_name, int len)
{
        int i, j;
        u32 app_id = (u32)cd->app_unitcfg;

        memset(app_name, 0, len);
        for (i = 0, j = 0; j < min(len, 4); j++) {
                char ch = (char)((app_id >> (24 - j*8)) & 0xff);

                if (ch == ' ')
                        continue;
                app_name[i++] = isprint(ch) ? ch : 'X';
        }
        return i;
}

/**
 * genwqe_init_crc32() - Prepare a lookup table for fast crc32 calculations
 *
 * Existing kernel functions seem to use a different polynom,
 * therefore we could not use them here.
 *
 * Genwqe's Polynomial = 0x20044009
 */
#define CRC32_POLYNOMIAL        0x20044009
static u32 crc32_tab[256];      /* crc32 lookup table */

void genwqe_init_crc32(void)
{
        int i, j;
        u32 crc;

        for (i = 0;  i < 256;  i++) {
                crc = i << 24;
                for (j = 0;  j < 8;  j++) {
                        if (crc & 0x80000000)
                                crc = (crc << 1) ^ CRC32_POLYNOMIAL;
                        else
                                crc = (crc << 1);
                }
                crc32_tab[i] = crc;
        }
}

/**
 * genwqe_crc32() - Generate 32-bit crc as required for DDCBs
 * @buff:       pointer to data buffer
 * @len:        length of data for calculation
 * @init:       initial crc (0xffffffff at start)
 *
 * polynomial = x^32 * + x^29 + x^18 + x^14 + x^3 + 1 (0x20044009)

 * Example: 4 bytes 0x01 0x02 0x03 0x04 with init=0xffffffff should
 * result in a crc32 of 0xf33cb7d3.
 *
 * The existing kernel crc functions did not cover this polynom yet.
 *
 * Return: crc32 checksum.
 */
u32 genwqe_crc32(u8 *buff, size_t len, u32 init)
{
        int i;
        u32 crc;

        crc = init;
        while (len--) {
                i = ((crc >> 24) ^ *buff++) & 0xFF;
                crc = (crc << 8) ^ crc32_tab[i];
        }
        return crc;
}

void *__genwqe_alloc_consistent(struct genwqe_dev *cd, size_t size,
                               dma_addr_t *dma_handle)
{
        if (get_order(size) > MAX_ORDER)
                return NULL;

        return pci_alloc_consistent(cd->pci_dev, size, dma_handle);
}

void __genwqe_free_consistent(struct genwqe_dev *cd, size_t size,
                             void *vaddr, dma_addr_t dma_handle)
{
        if (vaddr == NULL)
                return;

        pci_free_consistent(cd->pci_dev, size, vaddr, dma_handle);
}

static void genwqe_unmap_pages(struct genwqe_dev *cd, dma_addr_t *dma_list,
                              int num_pages)
{
        int i;
        struct pci_dev *pci_dev = cd->pci_dev;

        for (i = 0; (i < num_pages) && (dma_list[i] != 0x0); i++) {
                pci_unmap_page(pci_dev, dma_list[i],
                               PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
                dma_list[i] = 0x0;
        }
}

static int genwqe_map_pages(struct genwqe_dev *cd,
                           struct page **page_list, int num_pages,
                           dma_addr_t *dma_list)
{
        int i;
        struct pci_dev *pci_dev = cd->pci_dev;

        /* establish DMA mapping for requested pages */
        for (i = 0; i < num_pages; i++) {
                dma_addr_t daddr;

                dma_list[i] = 0x0;
                daddr = pci_map_page(pci_dev, page_list[i],
                                     0,  /* map_offs */
                                     PAGE_SIZE,
                                     PCI_DMA_BIDIRECTIONAL);  /* FIXME rd/rw */

                if (pci_dma_mapping_error(pci_dev, daddr)) {
                        dev_err(&pci_dev->dev,
                                "[%s] err: no dma addr daddr=%016llx!\n",
                                __func__, (long long)daddr);
                        goto err;
                }

                dma_list[i] = daddr;
        }
        return 0;

 err:
        genwqe_unmap_pages(cd, dma_list, num_pages);
        return -EIO;
}

static int genwqe_sgl_size(int num_pages)
{
        int len, num_tlb = num_pages / 7;

        len = sizeof(struct sg_entry) * (num_pages+num_tlb + 1);
        return roundup(len, PAGE_SIZE);
}

/**
 * genwqe_alloc_sync_sgl() - Allocate memory for sgl and overlapping pages
 *
 * Allocates memory for sgl and overlapping pages. Pages which might
 * overlap other user-space memory blocks are being cached for DMAs,
 * such that we do not run into syncronization issues. Data is copied
 * from user-space into the cached pages.
 */
int genwqe_alloc_sync_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl,
                          void __user *user_addr, size_t user_size)
{
        int rc;
        struct pci_dev *pci_dev = cd->pci_dev;

        sgl->fpage_offs = offset_in_page((unsigned long)user_addr);
        sgl->fpage_size = min_t(size_t, PAGE_SIZE-sgl->fpage_offs, user_size);
        sgl->nr_pages = DIV_ROUND_UP(sgl->fpage_offs + user_size, PAGE_SIZE);
        sgl->lpage_size = (user_size - sgl->fpage_size) % PAGE_SIZE;

        dev_dbg(&pci_dev->dev, "[%s] uaddr=%p usize=%8ld nr_pages=%ld fpage_offs=%lx fpage_size=%ld lpage_size=%ld\n",
                __func__, user_addr, user_size, sgl->nr_pages,
                sgl->fpage_offs, sgl->fpage_size, sgl->lpage_size);

        sgl->user_addr = user_addr;
        sgl->user_size = user_size;
        sgl->sgl_size = genwqe_sgl_size(sgl->nr_pages);

        if (get_order(sgl->sgl_size) > MAX_ORDER) {
                dev_err(&pci_dev->dev,
                        "[%s] err: too much memory requested!\n", __func__);
                return -ENOMEM;
        }

        sgl->sgl = __genwqe_alloc_consistent(cd, sgl->sgl_size,
                                             &sgl->sgl_dma_addr);
        if (sgl->sgl == NULL) {
                dev_err(&pci_dev->dev,
                        "[%s] err: no memory available!\n", __func__);
                return -ENOMEM;
        }

        /* Only use buffering on incomplete pages */
        if ((sgl->fpage_size != 0) && (sgl->fpage_size != PAGE_SIZE)) {
                sgl->fpage = __genwqe_alloc_consistent(cd, PAGE_SIZE,
                                                       &sgl->fpage_dma_addr);
                if (sgl->fpage == NULL)
                        goto err_out;

                /* Sync with user memory */
                if (copy_from_user(sgl->fpage + sgl->fpage_offs,
                                   user_addr, sgl->fpage_size)) {
                        rc = -EFAULT;
                        goto err_out;
                }
        }
        if (sgl->lpage_size != 0) {
                sgl->lpage = __genwqe_alloc_consistent(cd, PAGE_SIZE,
                                                       &sgl->lpage_dma_addr);
                if (sgl->lpage == NULL)
                        goto err_out1;

                /* Sync with user memory */
                if (copy_from_user(sgl->lpage, user_addr + user_size -
                                   sgl->lpage_size, sgl->lpage_size)) {
                        rc = -EFAULT;
                        goto err_out1;
                }
        }
        return 0;

 err_out1:
        __genwqe_free_consistent(cd, PAGE_SIZE, sgl->fpage,
                                 sgl->fpage_dma_addr);
 err_out:
        __genwqe_free_consistent(cd, sgl->sgl_size, sgl->sgl,
                                 sgl->sgl_dma_addr);
        return -ENOMEM;
}

int genwqe_setup_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl,
                     dma_addr_t *dma_list)
{
        int i = 0, j = 0, p;
        unsigned long dma_offs, map_offs;
        dma_addr_t prev_daddr = 0;
        struct sg_entry *s, *last_s = NULL;
        size_t size = sgl->user_size;

        dma_offs = 128;         /* next block if needed/dma_offset */
        map_offs = sgl->fpage_offs; /* offset in first page */

        s = &sgl->sgl[0];       /* first set of 8 entries */
        p = 0;                  /* page */
        while (p < sgl->nr_pages) {
                dma_addr_t daddr;
                unsigned int size_to_map;

                /* always write the chaining entry, cleanup is done later */
                j = 0;
                s[j].target_addr = cpu_to_be64(sgl->sgl_dma_addr + dma_offs);
                s[j].len         = cpu_to_be32(128);
                s[j].flags       = cpu_to_be32(SG_CHAINED);
                j++;

                while (j < 8) {
                        /* DMA mapping for requested page, offs, size */
                        size_to_map = min(size, PAGE_SIZE - map_offs);

                        if ((p == 0) && (sgl->fpage != NULL)) {
                                daddr = sgl->fpage_dma_addr + map_offs;

                        } else if ((p == sgl->nr_pages - 1) &&
                                   (sgl->lpage != NULL)) {
                                daddr = sgl->lpage_dma_addr;
                        } else {
                                daddr = dma_list[p] + map_offs;
                        }

                        size -= size_to_map;
                        map_offs = 0;

                        if (prev_daddr == daddr) {
                                u32 prev_len = be32_to_cpu(last_s->len);

                                /* pr_info("daddr combining: "
                                        "%016llx/%08x -> %016llx\n",
                                        prev_daddr, prev_len, daddr); */

                                last_s->len = cpu_to_be32(prev_len +
                                                          size_to_map);

                                p++; /* process next page */
                                if (p == sgl->nr_pages)
                                        goto fixup;  /* nothing to do */

                                prev_daddr = daddr + size_to_map;
                                continue;
                        }

                        /* start new entry */
                        s[j].target_addr = cpu_to_be64(daddr);
                        s[j].len         = cpu_to_be32(size_to_map);
                        s[j].flags       = cpu_to_be32(SG_DATA);
                        prev_daddr = daddr + size_to_map;
                        last_s = &s[j];
                        j++;

                        p++;    /* process next page */
                        if (p == sgl->nr_pages)
                                goto fixup;  /* nothing to do */
                }
                dma_offs += 128;
                s += 8;         /* continue 8 elements further */
        }
 fixup:
        if (j == 1) {           /* combining happend on last entry! */
                s -= 8;         /* full shift needed on previous sgl block */
                j =  7;         /* shift all elements */
        }

        for (i = 0; i < j; i++) /* move elements 1 up */
                s[i] = s[i + 1];

        s[i].target_addr = cpu_to_be64(0);
        s[i].len         = cpu_to_be32(0);
        s[i].flags       = cpu_to_be32(SG_END_LIST);
        return 0;
}

/**
 * genwqe_free_sync_sgl() - Free memory for sgl and overlapping pages
 *
 * After the DMA transfer has been completed we free the memory for
 * the sgl and the cached pages. Data is being transfered from cached
 * pages into user-space buffers.
 */
int genwqe_free_sync_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl)
{
        int rc = 0;
        struct pci_dev *pci_dev = cd->pci_dev;

        if (sgl->fpage) {
                if (copy_to_user(sgl->user_addr, sgl->fpage + sgl->fpage_offs,
                                 sgl->fpage_size)) {
                        dev_err(&pci_dev->dev, "[%s] err: copying fpage!\n",
                                __func__);
                        rc = -EFAULT;
                }
                __genwqe_free_consistent(cd, PAGE_SIZE, sgl->fpage,
                                         sgl->fpage_dma_addr);
                sgl->fpage = NULL;
                sgl->fpage_dma_addr = 0;
        }
        if (sgl->lpage) {
                if (copy_to_user(sgl->user_addr + sgl->user_size -
                                 sgl->lpage_size, sgl->lpage,
                                 sgl->lpage_size)) {
                        dev_err(&pci_dev->dev, "[%s] err: copying lpage!\n",
                                __func__);
                        rc = -EFAULT;
                }
                __genwqe_free_consistent(cd, PAGE_SIZE, sgl->lpage,
                                         sgl->lpage_dma_addr);
                sgl->lpage = NULL;
                sgl->lpage_dma_addr = 0;
        }
        __genwqe_free_consistent(cd, sgl->sgl_size, sgl->sgl,
                                 sgl->sgl_dma_addr);

        sgl->sgl = NULL;
        sgl->sgl_dma_addr = 0x0;
        sgl->sgl_size = 0;
        return rc;
}

/**
 * free_user_pages() - Give pinned pages back
 *
 * Documentation of get_user_pages is in mm/memory.c:
 *
 * If the page is written to, set_page_dirty (or set_page_dirty_lock,
 * as appropriate) must be called after the page is finished with, and
 * before put_page is called.
 *
 * FIXME Could be of use to others and might belong in the generic
 * code, if others agree. E.g.
 *    ll_free_user_pages in drivers/staging/lustre/lustre/llite/rw26.c
 *    ceph_put_page_vector in net/ceph/pagevec.c
 *    maybe more?
 */
static int free_user_pages(struct page **page_list, unsigned int nr_pages,
                           int dirty)
{
        unsigned int i;

        for (i = 0; i < nr_pages; i++) {
                if (page_list[i] != NULL) {
                        if (dirty)
                                set_page_dirty_lock(page_list[i]);
                        put_page(page_list[i]);
                }
        }
        return 0;
}

/**
 * genwqe_user_vmap() - Map user-space memory to virtual kernel memory
 * @cd:         pointer to genwqe device
 * @m:          mapping params
 * @uaddr:      user virtual address
 * @size:       size of memory to be mapped
 *
 * We need to think about how we could speed this up. Of course it is
 * not a good idea to do this over and over again, like we are
 * currently doing it. Nevertheless, I am curious where on the path
 * the performance is spend. Most probably within the memory
 * allocation functions, but maybe also in the DMA mapping code.
 *
 * Restrictions: The maximum size of the possible mapping currently depends
 *               on the amount of memory we can get using kzalloc() for the
 *               page_list and pci_alloc_consistent for the sg_list.
 *               The sg_list is currently itself not scattered, which could
 *               be fixed with some effort. The page_list must be split into
 *               PAGE_SIZE chunks too. All that will make the complicated
 *               code more complicated.
 *
 * Return: 0 if success
 */
int genwqe_user_vmap(struct genwqe_dev *cd, struct dma_mapping *m, void *uaddr,
                     unsigned long size, struct ddcb_requ *req)
{
        int rc = -EINVAL;
        unsigned long data, offs;
        struct pci_dev *pci_dev = cd->pci_dev;

        if ((uaddr == NULL) || (size == 0)) {
                m->size = 0;    /* mark unused and not added */
                return -EINVAL;
        }
        m->u_vaddr = uaddr;
        m->size    = size;

        /* determine space needed for page_list. */
        data = (unsigned long)uaddr;
        offs = offset_in_page(data);
        m->nr_pages = DIV_ROUND_UP(offs + size, PAGE_SIZE);

        m->page_list = kcalloc(m->nr_pages,
                               sizeof(struct page *) + sizeof(dma_addr_t),
                               GFP_KERNEL);
        if (!m->page_list) {
                dev_err(&pci_dev->dev, "err: alloc page_list failed\n");
                m->nr_pages = 0;
                m->u_vaddr = NULL;
                m->size = 0;    /* mark unused and not added */
                return -ENOMEM;
        }
        m->dma_list = (dma_addr_t *)(m->page_list + m->nr_pages);

        /* pin user pages in memory */
        rc = get_user_pages_fast(data & PAGE_MASK, /* page aligned addr */
                                 m->nr_pages,
                                 1,             /* write by caller */
                                 m->page_list); /* ptrs to pages */
        if (rc < 0)
                goto fail_get_user_pages;

        /* assumption: get_user_pages can be killed by signals. */
        if (rc < m->nr_pages) {
                free_user_pages(m->page_list, rc, 0);
                rc = -EFAULT;
                goto fail_get_user_pages;
        }

        rc = genwqe_map_pages(cd, m->page_list, m->nr_pages, m->dma_list);
        if (rc != 0)
                goto fail_free_user_pages;

        return 0;

 fail_free_user_pages:
        free_user_pages(m->page_list, m->nr_pages, 0);

 fail_get_user_pages:
        kfree(m->page_list);
        m->page_list = NULL;
        m->dma_list = NULL;
        m->nr_pages = 0;
        m->u_vaddr = NULL;
        m->size = 0;            /* mark unused and not added */
        return rc;
}

/**
 * genwqe_user_vunmap() - Undo mapping of user-space mem to virtual kernel
 *                        memory
 * @cd:         pointer to genwqe device
 * @m:          mapping params
 */
int genwqe_user_vunmap(struct genwqe_dev *cd, struct dma_mapping *m,
                       struct ddcb_requ *req)
{
        struct pci_dev *pci_dev = cd->pci_dev;

        if (!dma_mapping_used(m)) {
                dev_err(&pci_dev->dev, "[%s] err: mapping %p not used!\n",
                        __func__, m);
                return -EINVAL;
        }

        if (m->dma_list)
                genwqe_unmap_pages(cd, m->dma_list, m->nr_pages);

        if (m->page_list) {
                free_user_pages(m->page_list, m->nr_pages, 1);

                kfree(m->page_list);
                m->page_list = NULL;
                m->dma_list = NULL;
                m->nr_pages = 0;
        }

        m->u_vaddr = NULL;
        m->size = 0;            /* mark as unused and not added */
        return 0;
}

/**
 * genwqe_card_type() - Get chip type SLU Configuration Register
 * @cd:         pointer to the genwqe device descriptor
 * Return: 0: Altera Stratix-IV 230
 *         1: Altera Stratix-IV 530
 *         2: Altera Stratix-V A4
 *         3: Altera Stratix-V A7
 */
u8 genwqe_card_type(struct genwqe_dev *cd)
{
        u64 card_type = cd->slu_unitcfg;

        return (u8)((card_type & IO_SLU_UNITCFG_TYPE_MASK) >> 20);
}

/**
 * genwqe_card_reset() - Reset the card
 * @cd:         pointer to the genwqe device descriptor
 */
int genwqe_card_reset(struct genwqe_dev *cd)
{
        u64 softrst;
        struct pci_dev *pci_dev = cd->pci_dev;

        if (!genwqe_is_privileged(cd))
                return -ENODEV;

        /* new SL */
        __genwqe_writeq(cd, IO_SLC_CFGREG_SOFTRESET, 0x1ull);
        msleep(1000);
        __genwqe_readq(cd, IO_HSU_FIR_CLR);
        __genwqe_readq(cd, IO_APP_FIR_CLR);
        __genwqe_readq(cd, IO_SLU_FIR_CLR);

        /*
         * Read-modify-write to preserve the stealth bits
         *
         * For SL >= 039, Stealth WE bit allows removing
         * the read-modify-wrote.
         * r-m-w may require a mask 0x3C to avoid hitting hard
         * reset again for error reset (should be 0, chicken).
         */
        softrst = __genwqe_readq(cd, IO_SLC_CFGREG_SOFTRESET) & 0x3cull;
        __genwqe_writeq(cd, IO_SLC_CFGREG_SOFTRESET, softrst | 0x2ull);

        /* give ERRORRESET some time to finish */
        msleep(50);

        if (genwqe_need_err_masking(cd)) {
                dev_info(&pci_dev->dev,
                         "[%s] masking errors for old bitstreams\n", __func__);
                __genwqe_writeq(cd, IO_SLC_MISC_DEBUG, 0x0aull);
        }
        return 0;
}

int genwqe_read_softreset(struct genwqe_dev *cd)
{
        u64 bitstream;

        if (!genwqe_is_privileged(cd))
                return -ENODEV;

        bitstream = __genwqe_readq(cd, IO_SLU_BITSTREAM) & 0x1;
        cd->softreset = (bitstream == 0) ? 0x8ull : 0xcull;
        return 0;
}

/**
 * genwqe_set_interrupt_capability() - Configure MSI capability structure
 * @cd:         pointer to the device
 * Return: 0 if no error
 */
int genwqe_set_interrupt_capability(struct genwqe_dev *cd, int count)
{
        int rc;
        struct pci_dev *pci_dev = cd->pci_dev;

        rc = pci_enable_msi_range(pci_dev, 1, count);
        if (rc < 0)
                return rc;

        cd->flags |= GENWQE_FLAG_MSI_ENABLED;
        return 0;
}

/**
 * genwqe_reset_interrupt_capability() - Undo genwqe_set_interrupt_capability()
 * @cd:         pointer to the device
 */
void genwqe_reset_interrupt_capability(struct genwqe_dev *cd)
{
        struct pci_dev *pci_dev = cd->pci_dev;

        if (cd->flags & GENWQE_FLAG_MSI_ENABLED) {
                pci_disable_msi(pci_dev);
                cd->flags &= ~GENWQE_FLAG_MSI_ENABLED;
        }
}

/**
 * set_reg_idx() - Fill array with data. Ignore illegal offsets.
 * @cd:         card device
 * @r:          debug register array
 * @i:          index to desired entry
 * @m:          maximum possible entries
 * @addr:       addr which is read
 * @index:      index in debug array
 * @val:        read value
 */
static int set_reg_idx(struct genwqe_dev *cd, struct genwqe_reg *r,
                       unsigned int *i, unsigned int m, u32 addr, u32 idx,
                       u64 val)
{
        if (WARN_ON_ONCE(*i >= m))
                return -EFAULT;

        r[*i].addr = addr;
        r[*i].idx = idx;
        r[*i].val = val;
        ++*i;
        return 0;
}

static int set_reg(struct genwqe_dev *cd, struct genwqe_reg *r,
                   unsigned int *i, unsigned int m, u32 addr, u64 val)
{
        return set_reg_idx(cd, r, i, m, addr, 0, val);
}

int genwqe_read_ffdc_regs(struct genwqe_dev *cd, struct genwqe_reg *regs,
                         unsigned int max_regs, int all)
{
        unsigned int i, j, idx = 0;
        u32 ufir_addr, ufec_addr, sfir_addr, sfec_addr;
        u64 gfir, sluid, appid, ufir, ufec, sfir, sfec;

        /* Global FIR */
        gfir = __genwqe_readq(cd, IO_SLC_CFGREG_GFIR);
        set_reg(cd, regs, &idx, max_regs, IO_SLC_CFGREG_GFIR, gfir);

        /* UnitCfg for SLU */
        sluid = __genwqe_readq(cd, IO_SLU_UNITCFG); /* 0x00000000 */
        set_reg(cd, regs, &idx, max_regs, IO_SLU_UNITCFG, sluid);

        /* UnitCfg for APP */
        appid = __genwqe_readq(cd, IO_APP_UNITCFG); /* 0x02000000 */
        set_reg(cd, regs, &idx, max_regs, IO_APP_UNITCFG, appid);

        /* Check all chip Units */
        for (i = 0; i < GENWQE_MAX_UNITS; i++) {

                /* Unit FIR */
                ufir_addr = (i << 24) | 0x008;
                ufir = __genwqe_readq(cd, ufir_addr);
                set_reg(cd, regs, &idx, max_regs, ufir_addr, ufir);

                /* Unit FEC */
                ufec_addr = (i << 24) | 0x018;
                ufec = __genwqe_readq(cd, ufec_addr);
                set_reg(cd, regs, &idx, max_regs, ufec_addr, ufec);

                for (j = 0; j < 64; j++) {
                        /* wherever there is a primary 1, read the 2ndary */
                        if (!all && (!(ufir & (1ull << j))))
                                continue;

                        sfir_addr = (i << 24) | (0x100 + 8 * j);
                        sfir = __genwqe_readq(cd, sfir_addr);
                        set_reg(cd, regs, &idx, max_regs, sfir_addr, sfir);

                        sfec_addr = (i << 24) | (0x300 + 8 * j);
                        sfec = __genwqe_readq(cd, sfec_addr);
                        set_reg(cd, regs, &idx, max_regs, sfec_addr, sfec);
                }
        }

        /* fill with invalid data until end */
        for (i = idx; i < max_regs; i++) {
                regs[i].addr = 0xffffffff;
                regs[i].val = 0xffffffffffffffffull;
        }
        return idx;
}

/**
 * genwqe_ffdc_buff_size() - Calculates the number of dump registers
 */
int genwqe_ffdc_buff_size(struct genwqe_dev *cd, int uid)
{
        int entries = 0, ring, traps, traces, trace_entries;
        u32 eevptr_addr, l_addr, d_len, d_type;
        u64 eevptr, val, addr;

        eevptr_addr = GENWQE_UID_OFFS(uid) | IO_EXTENDED_ERROR_POINTER;
        eevptr = __genwqe_readq(cd, eevptr_addr);

        if ((eevptr != 0x0) && (eevptr != -1ull)) {
                l_addr = GENWQE_UID_OFFS(uid) | eevptr;

                while (1) {
                        val = __genwqe_readq(cd, l_addr);

                        if ((val == 0x0) || (val == -1ull))
                                break;

                        /* 38:24 */
                        d_len  = (val & 0x0000007fff000000ull) >> 24;

                        /* 39 */
                        d_type = (val & 0x0000008000000000ull) >> 36;

                        if (d_type) {   /* repeat */
                                entries += d_len;
                        } else {        /* size in bytes! */
                                entries += d_len >> 3;
                        }

                        l_addr += 8;
                }
        }

        for (ring = 0; ring < 8; ring++) {
                addr = GENWQE_UID_OFFS(uid) | IO_EXTENDED_DIAG_MAP(ring);
                val = __genwqe_readq(cd, addr);

                if ((val == 0x0ull) || (val == -1ull))
                        continue;

                traps = (val >> 24) & 0xff;
                traces = (val >> 16) & 0xff;
                trace_entries = val & 0xffff;

                entries += traps + (traces * trace_entries);
        }
        return entries;
}

/**
 * genwqe_ffdc_buff_read() - Implements LogoutExtendedErrorRegisters procedure
 */
int genwqe_ffdc_buff_read(struct genwqe_dev *cd, int uid,
                          struct genwqe_reg *regs, unsigned int max_regs)
{
        int i, traps, traces, trace, trace_entries, trace_entry, ring;
        unsigned int idx = 0;
        u32 eevptr_addr, l_addr, d_addr, d_len, d_type;
        u64 eevptr, e, val, addr;

        eevptr_addr = GENWQE_UID_OFFS(uid) | IO_EXTENDED_ERROR_POINTER;
        eevptr = __genwqe_readq(cd, eevptr_addr);

        if ((eevptr != 0x0) && (eevptr != 0xffffffffffffffffull)) {
                l_addr = GENWQE_UID_OFFS(uid) | eevptr;
                while (1) {
                        e = __genwqe_readq(cd, l_addr);
                        if ((e == 0x0) || (e == 0xffffffffffffffffull))
                                break;

                        d_addr = (e & 0x0000000000ffffffull);       /* 23:0 */
                        d_len  = (e & 0x0000007fff000000ull) >> 24; /* 38:24 */
                        d_type = (e & 0x0000008000000000ull) >> 36; /* 39 */
                        d_addr |= GENWQE_UID_OFFS(uid);

                        if (d_type) {
                                for (i = 0; i < (int)d_len; i++) {
                                        val = __genwqe_readq(cd, d_addr);
                                        set_reg_idx(cd, regs, &idx, max_regs,
                                                    d_addr, i, val);
                                }
                        } else {
                                d_len >>= 3; /* Size in bytes! */
                                for (i = 0; i < (int)d_len; i++, d_addr += 8) {
                                        val = __genwqe_readq(cd, d_addr);
                                        set_reg_idx(cd, regs, &idx, max_regs,
                                                    d_addr, 0, val);
                                }
                        }
                        l_addr += 8;
                }
        }

        /*
         * To save time, there are only 6 traces poplulated on Uid=2,
         * Ring=1. each with iters=512.
         */
        for (ring = 0; ring < 8; ring++) { /* 0 is fls, 1 is fds,
                                              2...7 are ASI rings */
                addr = GENWQE_UID_OFFS(uid) | IO_EXTENDED_DIAG_MAP(ring);
                val = __genwqe_readq(cd, addr);

                if ((val == 0x0ull) || (val == -1ull))
                        continue;

                traps = (val >> 24) & 0xff;     /* Number of Traps      */
                traces = (val >> 16) & 0xff;    /* Number of Traces     */
                trace_entries = val & 0xffff;   /* Entries per trace    */

                /* Note: This is a combined loop that dumps both the traps */
                /* (for the trace == 0 case) as well as the traces 1 to    */
                /* 'traces'.                                               */
                for (trace = 0; trace <= traces; trace++) {
                        u32 diag_sel =
                                GENWQE_EXTENDED_DIAG_SELECTOR(ring, trace);

                        addr = (GENWQE_UID_OFFS(uid) |
                                IO_EXTENDED_DIAG_SELECTOR);
                        __genwqe_writeq(cd, addr, diag_sel);

                        for (trace_entry = 0;
                             trace_entry < (trace ? trace_entries : traps);
                             trace_entry++) {
                                addr = (GENWQE_UID_OFFS(uid) |
                                        IO_EXTENDED_DIAG_READ_MBX);
                                val = __genwqe_readq(cd, addr);
                                set_reg_idx(cd, regs, &idx, max_regs, addr,
                                            (diag_sel<<16) | trace_entry, val);
                        }
                }
        }
        return 0;
}

/**
 * genwqe_write_vreg() - Write register in virtual window
 *
 * Note, these registers are only accessible to the PF through the
 * VF-window. It is not intended for the VF to access.
 */
int genwqe_write_vreg(struct genwqe_dev *cd, u32 reg, u64 val, int func)
{
        __genwqe_writeq(cd, IO_PF_SLC_VIRTUAL_WINDOW, func & 0xf);
        __genwqe_writeq(cd, reg, val);
        return 0;
}

/**
 * genwqe_read_vreg() - Read register in virtual window
 *
 * Note, these registers are only accessible to the PF through the
 * VF-window. It is not intended for the VF to access.
 */
u64 genwqe_read_vreg(struct genwqe_dev *cd, u32 reg, int func)
{
        __genwqe_writeq(cd, IO_PF_SLC_VIRTUAL_WINDOW, func & 0xf);

        return __genwqe_readq(cd, reg);
}

/**
 * genwqe_base_clock_frequency() - Deteremine base clock frequency of the card
 *
 * Note: From a design perspective it turned out to be a bad idea to
 * use codes here to specifiy the frequency/speed values. An old
 * driver cannot understand new codes and is therefore always a
 * problem. Better is to measure out the value or put the
 * speed/frequency directly into a register which is always a valid
 * value for old as well as for new software.
 *
 * Return: Card clock in MHz
 */
int genwqe_base_clock_frequency(struct genwqe_dev *cd)
{
        u16 speed;              /*         MHz  MHz  MHz  MHz */
        static const int speed_grade[] = { 250, 200, 166, 175 };

        speed = (u16)((cd->slu_unitcfg >> 28) & 0x0full);
        if (speed >= ARRAY_SIZE(speed_grade))
                return 0;       /* illegal value */

        return speed_grade[speed];
}

/**
 * genwqe_stop_traps() - Stop traps
 *
 * Before reading out the analysis data, we need to stop the traps.
 */
void genwqe_stop_traps(struct genwqe_dev *cd)
{
        __genwqe_writeq(cd, IO_SLC_MISC_DEBUG_SET, 0xcull);
}

/**
 * genwqe_start_traps() - Start traps
 *
 * After having read the data, we can/must enable the traps again.
 */
void genwqe_start_traps(struct genwqe_dev *cd)
{
        __genwqe_writeq(cd, IO_SLC_MISC_DEBUG_CLR, 0xcull);

        if (genwqe_need_err_masking(cd))
                __genwqe_writeq(cd, IO_SLC_MISC_DEBUG, 0x0aull);
}