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/*
* Copyright (c) 2015-2016 Quantenna Communications, Inc.
* All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* 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.
*
*/
#include <linux/types.h>
#include <linux/io.h>
#include "shm_ipc.h"
#undef pr_fmt
#define pr_fmt(fmt) "qtnfmac shm_ipc: %s: " fmt, __func__
static bool qtnf_shm_ipc_has_new_data(struct qtnf_shm_ipc *ipc)
{
const u32 flags = readl(&ipc->shm_region->headroom.hdr.flags);
return (flags & QTNF_SHM_IPC_NEW_DATA);
}
static void qtnf_shm_handle_new_data(struct qtnf_shm_ipc *ipc)
{
size_t size;
bool rx_buff_ok = true;
struct qtnf_shm_ipc_region_header __iomem *shm_reg_hdr;
shm_reg_hdr = &ipc->shm_region->headroom.hdr;
size = readw(&shm_reg_hdr->data_len);
if (unlikely(size == 0 || size > QTN_IPC_MAX_DATA_SZ)) {
pr_err("wrong rx packet size: %zu\n", size);
rx_buff_ok = false;
} else {
memcpy_fromio(ipc->rx_data, ipc->shm_region->data, size);
}
writel(QTNF_SHM_IPC_ACK, &shm_reg_hdr->flags);
readl(&shm_reg_hdr->flags); /* flush PCIe write */
ipc->interrupt.fn(ipc->interrupt.arg);
if (likely(rx_buff_ok)) {
ipc->rx_packet_count++;
ipc->rx_callback.fn(ipc->rx_callback.arg, ipc->rx_data, size);
}
}
static void qtnf_shm_ipc_irq_work(struct work_struct *work)
{
struct qtnf_shm_ipc *ipc = container_of(work, struct qtnf_shm_ipc,
irq_work);
while (qtnf_shm_ipc_has_new_data(ipc))
qtnf_shm_handle_new_data(ipc);
}
static void qtnf_shm_ipc_irq_inbound_handler(struct qtnf_shm_ipc *ipc)
{
u32 flags;
flags = readl(&ipc->shm_region->headroom.hdr.flags);
if (flags & QTNF_SHM_IPC_NEW_DATA)
queue_work(ipc->workqueue, &ipc->irq_work);
}
static void qtnf_shm_ipc_irq_outbound_handler(struct qtnf_shm_ipc *ipc)
{
u32 flags;
if (!READ_ONCE(ipc->waiting_for_ack))
return;
flags = readl(&ipc->shm_region->headroom.hdr.flags);
if (flags & QTNF_SHM_IPC_ACK) {
WRITE_ONCE(ipc->waiting_for_ack, 0);
complete(&ipc->tx_completion);
}
}
int qtnf_shm_ipc_init(struct qtnf_shm_ipc *ipc,
enum qtnf_shm_ipc_direction direction,
struct qtnf_shm_ipc_region __iomem *shm_region,
struct workqueue_struct *workqueue,
const struct qtnf_shm_ipc_int *interrupt,
const struct qtnf_shm_ipc_rx_callback *rx_callback)
{
BUILD_BUG_ON(offsetof(struct qtnf_shm_ipc_region, data) !=
QTN_IPC_REG_HDR_SZ);
BUILD_BUG_ON(sizeof(struct qtnf_shm_ipc_region) > QTN_IPC_REG_SZ);
ipc->shm_region = shm_region;
ipc->direction = direction;
ipc->interrupt = *interrupt;
ipc->rx_callback = *rx_callback;
ipc->tx_packet_count = 0;
ipc->rx_packet_count = 0;
ipc->workqueue = workqueue;
ipc->waiting_for_ack = 0;
ipc->tx_timeout_count = 0;
switch (direction) {
case QTNF_SHM_IPC_OUTBOUND:
ipc->irq_handler = qtnf_shm_ipc_irq_outbound_handler;
break;
case QTNF_SHM_IPC_INBOUND:
ipc->irq_handler = qtnf_shm_ipc_irq_inbound_handler;
break;
default:
return -EINVAL;
}
INIT_WORK(&ipc->irq_work, qtnf_shm_ipc_irq_work);
init_completion(&ipc->tx_completion);
return 0;
}
void qtnf_shm_ipc_free(struct qtnf_shm_ipc *ipc)
{
complete_all(&ipc->tx_completion);
}
int qtnf_shm_ipc_send(struct qtnf_shm_ipc *ipc, const u8 *buf, size_t size)
{
int ret = 0;
struct qtnf_shm_ipc_region_header __iomem *shm_reg_hdr;
shm_reg_hdr = &ipc->shm_region->headroom.hdr;
if (unlikely(size > QTN_IPC_MAX_DATA_SZ))
return -E2BIG;
ipc->tx_packet_count++;
writew(size, &shm_reg_hdr->data_len);
memcpy_toio(ipc->shm_region->data, buf, size);
/* sync previous writes before proceeding */
dma_wmb();
WRITE_ONCE(ipc->waiting_for_ack, 1);
/* sync previous memory write before announcing new data ready */
wmb();
writel(QTNF_SHM_IPC_NEW_DATA, &shm_reg_hdr->flags);
readl(&shm_reg_hdr->flags); /* flush PCIe write */
ipc->interrupt.fn(ipc->interrupt.arg);
if (!wait_for_completion_timeout(&ipc->tx_completion,
QTN_SHM_IPC_ACK_TIMEOUT)) {
ret = -ETIMEDOUT;
ipc->tx_timeout_count++;
pr_err("TX ACK timeout\n");
}
/* now we're not waiting for ACK even in case of timeout */
WRITE_ONCE(ipc->waiting_for_ack, 0);
return ret;
}
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