/*
 * Copyright (c) 2012-2015,2017 Qualcomm Atheros, Inc.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include "wmi.h"
#include "wil6210.h"
#include "txrx.h"
#include "pmc.h"

struct desc_alloc_info {
        dma_addr_t pa;
        void      *va;
};

static int wil_is_pmc_allocated(struct pmc_ctx *pmc)
{
        return !!pmc->pring_va;
}

void wil_pmc_init(struct wil6210_priv *wil)
{
        memset(&wil->pmc, 0, sizeof(struct pmc_ctx));
        mutex_init(&wil->pmc.lock);
}

/**
 * Allocate the physical ring (p-ring) and the required
 * number of descriptors of required size.
 * Initialize the descriptors as required by pmc dma.
 * The descriptors' buffers dwords are initialized to hold
 * dword's serial number in the lsw and reserved value
 * PCM_DATA_INVALID_DW_VAL in the msw.
 */
void wil_pmc_alloc(struct wil6210_priv *wil,
                   int num_descriptors,
                   int descriptor_size)
{
        u32 i;
        struct pmc_ctx *pmc = &wil->pmc;
        struct device *dev = wil_to_dev(wil);
        struct wmi_pmc_cmd pmc_cmd = {0};
        int last_cmd_err = -ENOMEM;

        mutex_lock(&pmc->lock);

        if (wil_is_pmc_allocated(pmc)) {
                /* sanity check */
                wil_err(wil, "ERROR pmc is already allocated\n");
                goto no_release_err;
        }
        if ((num_descriptors <= 0) || (descriptor_size <= 0)) {
                wil_err(wil,
                        "Invalid params num_descriptors(%d), descriptor_size(%d)\n",
                        num_descriptors, descriptor_size);
                last_cmd_err = -EINVAL;
                goto no_release_err;
        }

        if (num_descriptors > (1 << WIL_RING_SIZE_ORDER_MAX)) {
                wil_err(wil,
                        "num_descriptors(%d) exceeds max ring size %d\n",
                        num_descriptors, 1 << WIL_RING_SIZE_ORDER_MAX);
                last_cmd_err = -EINVAL;
                goto no_release_err;
        }

        if (num_descriptors > INT_MAX / descriptor_size) {
                wil_err(wil,
                        "Overflow in num_descriptors(%d)*descriptor_size(%d)\n",
                        num_descriptors, descriptor_size);
                last_cmd_err = -EINVAL;
                goto no_release_err;
        }

        pmc->num_descriptors = num_descriptors;
        pmc->descriptor_size = descriptor_size;

        wil_dbg_misc(wil, "pmc_alloc: %d descriptors x %d bytes each\n",
                     num_descriptors, descriptor_size);

        /* allocate descriptors info list in pmc context*/
        pmc->descriptors = kcalloc(num_descriptors,
                                  sizeof(struct desc_alloc_info),
                                  GFP_KERNEL);
        if (!pmc->descriptors) {
                wil_err(wil, "ERROR allocating pmc skb list\n");
                goto no_release_err;
        }

        wil_dbg_misc(wil, "pmc_alloc: allocated descriptors info list %p\n",
                     pmc->descriptors);

        /* Allocate pring buffer and descriptors.
         * vring->va should be aligned on its size rounded up to power of 2
         * This is granted by the dma_alloc_coherent.
         *
         * HW has limitation that all vrings addresses must share the same
         * upper 16 msb bits part of 48 bits address. To workaround that,
         * if we are using 48 bit addresses switch to 32 bit allocation
         * before allocating vring memory.
         *
         * There's no check for the return value of dma_set_mask_and_coherent,
         * since we assume if we were able to set the mask during
         * initialization in this system it will not fail if we set it again
         */
        if (wil->use_extended_dma_addr)
                dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));

        pmc->pring_va = dma_alloc_coherent(dev,
                        sizeof(struct vring_tx_desc) * num_descriptors,
                        &pmc->pring_pa,
                        GFP_KERNEL);

        if (wil->use_extended_dma_addr)
                dma_set_mask_and_coherent(dev, DMA_BIT_MASK(48));

        wil_dbg_misc(wil,
                     "pmc_alloc: allocated pring %p => %pad. %zd x %d = total %zd bytes\n",
                     pmc->pring_va, &pmc->pring_pa,
                     sizeof(struct vring_tx_desc),
                     num_descriptors,
                     sizeof(struct vring_tx_desc) * num_descriptors);

        if (!pmc->pring_va) {
                wil_err(wil, "ERROR allocating pmc pring\n");
                goto release_pmc_skb_list;
        }

        /* initially, all descriptors are SW owned
         * For Tx, Rx, and PMC, ownership bit is at the same location, thus
         * we can use any
         */
        for (i = 0; i < num_descriptors; i++) {
                struct vring_tx_desc *_d = &pmc->pring_va[i];
                struct vring_tx_desc dd = {}, *d = &dd;
                int j = 0;

                pmc->descriptors[i].va = dma_alloc_coherent(dev,
                        descriptor_size,
                        &pmc->descriptors[i].pa,
                        GFP_KERNEL);

                if (unlikely(!pmc->descriptors[i].va)) {
                        wil_err(wil, "ERROR allocating pmc descriptor %d", i);
                        goto release_pmc_skbs;
                }

                for (j = 0; j < descriptor_size / sizeof(u32); j++) {
                        u32 *p = (u32 *)pmc->descriptors[i].va + j;
                        *p = PCM_DATA_INVALID_DW_VAL | j;
                }

                /* configure dma descriptor */
                d->dma.addr.addr_low =
                        cpu_to_le32(lower_32_bits(pmc->descriptors[i].pa));
                d->dma.addr.addr_high =
                        cpu_to_le16((u16)upper_32_bits(pmc->descriptors[i].pa));
                d->dma.status = 0; /* 0 = HW_OWNED */
                d->dma.length = cpu_to_le16(descriptor_size);
                d->dma.d0 = BIT(9) | RX_DMA_D0_CMD_DMA_IT;
                *_d = *d;
        }

        wil_dbg_misc(wil, "pmc_alloc: allocated successfully\n");

        pmc_cmd.op = WMI_PMC_ALLOCATE;
        pmc_cmd.ring_size = cpu_to_le16(pmc->num_descriptors);
        pmc_cmd.mem_base = cpu_to_le64(pmc->pring_pa);

        wil_dbg_misc(wil, "pmc_alloc: send WMI_PMC_CMD with ALLOCATE op\n");
        pmc->last_cmd_status = wmi_send(wil,
                                        WMI_PMC_CMDID,
                                        &pmc_cmd,
                                        sizeof(pmc_cmd));
        if (pmc->last_cmd_status) {
                wil_err(wil,
                        "WMI_PMC_CMD with ALLOCATE op failed with status %d",
                        pmc->last_cmd_status);
                goto release_pmc_skbs;
        }

        mutex_unlock(&pmc->lock);

        return;

release_pmc_skbs:
        wil_err(wil, "exit on error: Releasing skbs...\n");
        for (i = 0; i < num_descriptors && pmc->descriptors[i].va; i++) {
                dma_free_coherent(dev,
                                  descriptor_size,
                                  pmc->descriptors[i].va,
                                  pmc->descriptors[i].pa);

                pmc->descriptors[i].va = NULL;
        }
        wil_err(wil, "exit on error: Releasing pring...\n");

        dma_free_coherent(dev,
                          sizeof(struct vring_tx_desc) * num_descriptors,
                          pmc->pring_va,
                          pmc->pring_pa);

        pmc->pring_va = NULL;

release_pmc_skb_list:
        wil_err(wil, "exit on error: Releasing descriptors info list...\n");
        kfree(pmc->descriptors);
        pmc->descriptors = NULL;

no_release_err:
        pmc->last_cmd_status = last_cmd_err;
        mutex_unlock(&pmc->lock);
}

/**
 * Traverse the p-ring and release all buffers.
 * At the end release the p-ring memory
 */
void wil_pmc_free(struct wil6210_priv *wil, int send_pmc_cmd)
{
        struct pmc_ctx *pmc = &wil->pmc;
        struct device *dev = wil_to_dev(wil);
        struct wmi_pmc_cmd pmc_cmd = {0};

        mutex_lock(&pmc->lock);

        pmc->last_cmd_status = 0;

        if (!wil_is_pmc_allocated(pmc)) {
                wil_dbg_misc(wil,
                             "pmc_free: Error, can't free - not allocated\n");
                pmc->last_cmd_status = -EPERM;
                mutex_unlock(&pmc->lock);
                return;
        }

        if (send_pmc_cmd) {
                wil_dbg_misc(wil, "send WMI_PMC_CMD with RELEASE op\n");
                pmc_cmd.op = WMI_PMC_RELEASE;
                pmc->last_cmd_status =
                                wmi_send(wil, WMI_PMC_CMDID, &pmc_cmd,
                                         sizeof(pmc_cmd));
                if (pmc->last_cmd_status) {
                        wil_err(wil,
                                "WMI_PMC_CMD with RELEASE op failed, status %d",
                                pmc->last_cmd_status);
                        /* There's nothing we can do with this error.
                         * Normally, it should never occur.
                         * Continue to freeing all memory allocated for pmc.
                         */
                }
        }

        if (pmc->pring_va) {
                size_t buf_size = sizeof(struct vring_tx_desc) *
                                  pmc->num_descriptors;

                wil_dbg_misc(wil, "pmc_free: free pring va %p\n",
                             pmc->pring_va);
                dma_free_coherent(dev, buf_size, pmc->pring_va, pmc->pring_pa);

                pmc->pring_va = NULL;
        } else {
                pmc->last_cmd_status = -ENOENT;
        }

        if (pmc->descriptors) {
                int i;

                for (i = 0;
                     i < pmc->num_descriptors && pmc->descriptors[i].va; i++) {
                        dma_free_coherent(dev,
                                          pmc->descriptor_size,
                                          pmc->descriptors[i].va,
                                          pmc->descriptors[i].pa);
                        pmc->descriptors[i].va = NULL;
                }
                wil_dbg_misc(wil, "pmc_free: free descriptor info %d/%d\n", i,
                             pmc->num_descriptors);
                wil_dbg_misc(wil,
                             "pmc_free: free pmc descriptors info list %p\n",
                             pmc->descriptors);
                kfree(pmc->descriptors);
                pmc->descriptors = NULL;
        } else {
                pmc->last_cmd_status = -ENOENT;
        }

        mutex_unlock(&pmc->lock);
}

/**
 * Status of the last operation requested via debugfs: alloc/free/read.
 * 0 - success or negative errno
 */
int wil_pmc_last_cmd_status(struct wil6210_priv *wil)
{
        wil_dbg_misc(wil, "pmc_last_cmd_status: status %d\n",
                     wil->pmc.last_cmd_status);

        return wil->pmc.last_cmd_status;
}

/**
 * Read from required position up to the end of current descriptor,
 * depends on descriptor size configured during alloc request.
 */
ssize_t wil_pmc_read(struct file *filp, char __user *buf, size_t count,
                     loff_t *f_pos)
{
        struct wil6210_priv *wil = filp->private_data;
        struct pmc_ctx *pmc = &wil->pmc;
        size_t retval = 0;
        unsigned long long idx;
        loff_t offset;
        size_t pmc_size;

        mutex_lock(&pmc->lock);

        if (!wil_is_pmc_allocated(pmc)) {
                wil_err(wil, "error, pmc is not allocated!\n");
                pmc->last_cmd_status = -EPERM;
                mutex_unlock(&pmc->lock);
                return -EPERM;
        }

        pmc_size = pmc->descriptor_size * pmc->num_descriptors;

        wil_dbg_misc(wil,
                     "pmc_read: size %u, pos %lld\n",
                     (u32)count, *f_pos);

        pmc->last_cmd_status = 0;

        idx = *f_pos;
        do_div(idx, pmc->descriptor_size);
        offset = *f_pos - (idx * pmc->descriptor_size);

        if (*f_pos >= pmc_size) {
                wil_dbg_misc(wil,
                             "pmc_read: reached end of pmc buf: %lld >= %u\n",
                             *f_pos, (u32)pmc_size);
                pmc->last_cmd_status = -ERANGE;
                goto out;
        }

        wil_dbg_misc(wil,
                     "pmc_read: read from pos %lld (descriptor %llu, offset %llu) %zu bytes\n",
                     *f_pos, idx, offset, count);

        /* if no errors, return the copied byte count */
        retval = simple_read_from_buffer(buf,
                                         count,
                                         &offset,
                                         pmc->descriptors[idx].va,
                                         pmc->descriptor_size);
        *f_pos += retval;
out:
        mutex_unlock(&pmc->lock);

        return retval;
}

loff_t wil_pmc_llseek(struct file *filp, loff_t off, int whence)
{
        loff_t newpos;
        struct wil6210_priv *wil = filp->private_data;
        struct pmc_ctx *pmc = &wil->pmc;
        size_t pmc_size;

        mutex_lock(&pmc->lock);

        if (!wil_is_pmc_allocated(pmc)) {
                wil_err(wil, "error, pmc is not allocated!\n");
                pmc->last_cmd_status = -EPERM;
                mutex_unlock(&pmc->lock);
                return -EPERM;
        }

        pmc_size = pmc->descriptor_size * pmc->num_descriptors;

        switch (whence) {
        case 0: /* SEEK_SET */
                newpos = off;
                break;

        case 1: /* SEEK_CUR */
                newpos = filp->f_pos + off;
                break;

        case 2: /* SEEK_END */
                newpos = pmc_size;
                break;

        default: /* can't happen */
                newpos = -EINVAL;
                goto out;
        }

        if (newpos < 0) {
                newpos = -EINVAL;
                goto out;
        }
        if (newpos > pmc_size)
                newpos = pmc_size;

        filp->f_pos = newpos;

out:
        mutex_unlock(&pmc->lock);

        return newpos;
}