/*
 * Copyright(c) 2015, 2016 Intel Corporation.
 *
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License 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.
 *
 * BSD LICENSE
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *  - Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *  - Neither the name of Intel Corporation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include <linux/delay.h>
#include "hfi.h"
#include "common.h"
#include "eprom.h"

/*
 * The EPROM is logically divided into three partitions:
 *      partition 0: the first 128K, visible from PCI ROM BAR
 *      partition 1: 4K config file (sector size)
 *      partition 2: the rest
 */
#define P0_SIZE (128 * 1024)
#define P1_SIZE   (4 * 1024)
#define P1_START P0_SIZE
#define P2_START (P0_SIZE + P1_SIZE)

/* controller page size, in bytes */
#define EP_PAGE_SIZE 256
#define EP_PAGE_MASK (EP_PAGE_SIZE - 1)
#define EP_PAGE_DWORDS (EP_PAGE_SIZE / sizeof(u32))

/* controller commands */
#define CMD_SHIFT 24
#define CMD_NOP                     (0)
#define CMD_READ_DATA(addr)         ((0x03 << CMD_SHIFT) | addr)
#define CMD_RELEASE_POWERDOWN_NOID  ((0xab << CMD_SHIFT))

/* controller interface speeds */
#define EP_SPEED_FULL 0x2       /* full speed */

/*
 * How long to wait for the EPROM to become available, in ms.
 * The spec 32 Mb EPROM takes around 40s to erase then write.
 * Double it for safety.
 */
#define EPROM_TIMEOUT 80000 /* ms */

/*
 * Read a 256 byte (64 dword) EPROM page.
 * All callers have verified the offset is at a page boundary.
 */
static void read_page(struct hfi1_devdata *dd, u32 offset, u32 *result)
{
        int i;

        write_csr(dd, ASIC_EEP_ADDR_CMD, CMD_READ_DATA(offset));
        for (i = 0; i < EP_PAGE_DWORDS; i++)
                result[i] = (u32)read_csr(dd, ASIC_EEP_DATA);
        write_csr(dd, ASIC_EEP_ADDR_CMD, CMD_NOP); /* close open page */
}

/*
 * Read length bytes starting at offset from the start of the EPROM.
 */
static int read_length(struct hfi1_devdata *dd, u32 start, u32 len, void *dest)
{
        u32 buffer[EP_PAGE_DWORDS];
        u32 end;
        u32 start_offset;
        u32 read_start;
        u32 bytes;

        if (len == 0)
                return 0;

        end = start + len;

        /*
         * Make sure the read range is not outside of the controller read
         * command address range.  Note that '>' is correct below - the end
         * of the range is OK if it stops at the limit, but no higher.
         */
        if (end > (1 << CMD_SHIFT))
                return -EINVAL;

        /* read the first partial page */
        start_offset = start & EP_PAGE_MASK;
        if (start_offset) {
                /* partial starting page */

                /* align and read the page that contains the start */
                read_start = start & ~EP_PAGE_MASK;
                read_page(dd, read_start, buffer);

                /* the rest of the page is available data */
                bytes = EP_PAGE_SIZE - start_offset;

                if (len <= bytes) {
                        /* end is within this page */
                        memcpy(dest, (u8 *)buffer + start_offset, len);
                        return 0;
                }

                memcpy(dest, (u8 *)buffer + start_offset, bytes);

                start += bytes;
                len -= bytes;
                dest += bytes;
        }
        /* start is now page aligned */

        /* read whole pages */
        while (len >= EP_PAGE_SIZE) {
                read_page(dd, start, buffer);
                memcpy(dest, buffer, EP_PAGE_SIZE);

                start += EP_PAGE_SIZE;
                len -= EP_PAGE_SIZE;
                dest += EP_PAGE_SIZE;
        }

        /* read the last partial page */
        if (len) {
                read_page(dd, start, buffer);
                memcpy(dest, buffer, len);
        }

        return 0;
}

/*
 * Initialize the EPROM handler.
 */
int eprom_init(struct hfi1_devdata *dd)
{
        int ret = 0;

        /* only the discrete chip has an EPROM */
        if (dd->pcidev->device != PCI_DEVICE_ID_INTEL0)
                return 0;

        /*
         * It is OK if both HFIs reset the EPROM as long as they don't
         * do it at the same time.
         */
        ret = acquire_chip_resource(dd, CR_EPROM, EPROM_TIMEOUT);
        if (ret) {
                dd_dev_err(dd,
                           "%s: unable to acquire EPROM resource, no EPROM support\n",
                           __func__);
                goto done_asic;
        }

        /* reset EPROM to be sure it is in a good state */

        /* set reset */
        write_csr(dd, ASIC_EEP_CTL_STAT, ASIC_EEP_CTL_STAT_EP_RESET_SMASK);
        /* clear reset, set speed */
        write_csr(dd, ASIC_EEP_CTL_STAT,
                  EP_SPEED_FULL << ASIC_EEP_CTL_STAT_RATE_SPI_SHIFT);

        /* wake the device with command "release powerdown NoID" */
        write_csr(dd, ASIC_EEP_ADDR_CMD, CMD_RELEASE_POWERDOWN_NOID);

        dd->eprom_available = true;
        release_chip_resource(dd, CR_EPROM);
done_asic:
        return ret;
}

/* magic character sequence that trails an image */
#define IMAGE_TRAIL_MAGIC "egamiAPO"

/*
 * Read all of partition 1.  The actual file is at the front.  Adjust
 * the returned size if a trailing image magic is found.
 */
static int read_partition_platform_config(struct hfi1_devdata *dd, void **data,
                                          u32 *size)
{
        void *buffer;
        void *p;
        u32 length;
        int ret;

        buffer = kmalloc(P1_SIZE, GFP_KERNEL);
        if (!buffer)
                return -ENOMEM;

        ret = read_length(dd, P1_START, P1_SIZE, buffer);
        if (ret) {
                kfree(buffer);
                return ret;
        }

        /* scan for image magic that may trail the actual data */
        p = strnstr(buffer, IMAGE_TRAIL_MAGIC, P1_SIZE);
        if (p)
                length = p - buffer;
        else
                length = P1_SIZE;

        *data = buffer;
        *size = length;
        return 0;
}

/*
 * Read the platform configuration file from the EPROM.
 *
 * On success, an allocated buffer containing the data and its size are
 * returned.  It is up to the caller to free this buffer.
 *
 * Return value:
 *   0        - success
 *   -ENXIO   - no EPROM is available
 *   -EBUSY   - not able to acquire access to the EPROM
 *   -ENOENT  - no recognizable file written
 *   -ENOMEM  - buffer could not be allocated
 */
int eprom_read_platform_config(struct hfi1_devdata *dd, void **data, u32 *size)
{
        u32 directory[EP_PAGE_DWORDS]; /* aligned buffer */
        int ret;

        if (!dd->eprom_available)
                return -ENXIO;

        ret = acquire_chip_resource(dd, CR_EPROM, EPROM_TIMEOUT);
        if (ret)
                return -EBUSY;

        /* read the last page of P0 for the EPROM format magic */
        ret = read_length(dd, P1_START - EP_PAGE_SIZE, EP_PAGE_SIZE, directory);
        if (ret)
                goto done;

        /* last dword of P0 contains a magic indicator */
        if (directory[EP_PAGE_DWORDS - 1] == 0) {
                /* partition format */
                ret = read_partition_platform_config(dd, data, size);
                goto done;
        }

        /* nothing recognized */
        ret = -ENOENT;

done:
        release_chip_resource(dd, CR_EPROM);
        return ret;
}