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// SPDX-License-Identifier: GPL-2.0-only
/*
* PXA2xx SPI DMA engine support.
*
* Copyright (C) 2013, 2021 Intel Corporation
* Author: Mika Westerberg <mika.westerberg@linux.intel.com>
*/
#include <linux/atomic.h>
#include <linux/dev_printk.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/errno.h>
#include <linux/irqreturn.h>
#include <linux/scatterlist.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/spi/spi.h>
#include "spi-pxa2xx.h"
struct device;
static void pxa2xx_spi_dma_transfer_complete(struct driver_data *drv_data,
bool error)
{
struct spi_message *msg = drv_data->controller->cur_msg;
/*
* It is possible that one CPU is handling ROR interrupt and other
* just gets DMA completion. Calling pump_transfers() twice for the
* same transfer leads to problems thus we prevent concurrent calls
* by using dma_running.
*/
if (atomic_dec_and_test(&drv_data->dma_running)) {
/*
* If the other CPU is still handling the ROR interrupt we
* might not know about the error yet. So we re-check the
* ROR bit here before we clear the status register.
*/
if (!error)
error = read_SSSR_bits(drv_data, drv_data->mask_sr) & SSSR_ROR;
/* Clear status & disable interrupts */
clear_SSCR1_bits(drv_data, drv_data->dma_cr1);
write_SSSR_CS(drv_data, drv_data->clear_sr);
if (!pxa25x_ssp_comp(drv_data))
pxa2xx_spi_write(drv_data, SSTO, 0);
if (error) {
/* In case we got an error we disable the SSP now */
pxa_ssp_disable(drv_data->ssp);
msg->status = -EIO;
}
spi_finalize_current_transfer(drv_data->controller);
}
}
static void pxa2xx_spi_dma_callback(void *data)
{
pxa2xx_spi_dma_transfer_complete(data, false);
}
static struct dma_async_tx_descriptor *
pxa2xx_spi_dma_prepare_one(struct driver_data *drv_data,
enum dma_transfer_direction dir,
struct spi_transfer *xfer)
{
enum dma_slave_buswidth width;
struct dma_slave_config cfg;
struct dma_chan *chan;
struct sg_table *sgt;
int ret;
switch (drv_data->n_bytes) {
case 1:
width = DMA_SLAVE_BUSWIDTH_1_BYTE;
break;
case 2:
width = DMA_SLAVE_BUSWIDTH_2_BYTES;
break;
default:
width = DMA_SLAVE_BUSWIDTH_4_BYTES;
break;
}
memset(&cfg, 0, sizeof(cfg));
cfg.direction = dir;
if (dir == DMA_MEM_TO_DEV) {
cfg.dst_addr = drv_data->ssp->phys_base + SSDR;
cfg.dst_addr_width = width;
cfg.dst_maxburst = drv_data->controller_info->dma_burst_size;
sgt = &xfer->tx_sg;
chan = drv_data->controller->dma_tx;
} else {
cfg.src_addr = drv_data->ssp->phys_base + SSDR;
cfg.src_addr_width = width;
cfg.src_maxburst = drv_data->controller_info->dma_burst_size;
sgt = &xfer->rx_sg;
chan = drv_data->controller->dma_rx;
}
ret = dmaengine_slave_config(chan, &cfg);
if (ret) {
dev_warn(drv_data->ssp->dev, "DMA slave config failed\n");
return NULL;
}
return dmaengine_prep_slave_sg(chan, sgt->sgl, sgt->nents, dir,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
}
irqreturn_t pxa2xx_spi_dma_transfer(struct driver_data *drv_data)
{
u32 status;
status = read_SSSR_bits(drv_data, drv_data->mask_sr);
if (status & SSSR_ROR) {
dev_err(drv_data->ssp->dev, "FIFO overrun\n");
dmaengine_terminate_async(drv_data->controller->dma_rx);
dmaengine_terminate_async(drv_data->controller->dma_tx);
pxa2xx_spi_dma_transfer_complete(drv_data, true);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
int pxa2xx_spi_dma_prepare(struct driver_data *drv_data,
struct spi_transfer *xfer)
{
struct dma_async_tx_descriptor *tx_desc, *rx_desc;
int err;
tx_desc = pxa2xx_spi_dma_prepare_one(drv_data, DMA_MEM_TO_DEV, xfer);
if (!tx_desc) {
dev_err(drv_data->ssp->dev, "failed to get DMA TX descriptor\n");
err = -EBUSY;
goto err_tx;
}
rx_desc = pxa2xx_spi_dma_prepare_one(drv_data, DMA_DEV_TO_MEM, xfer);
if (!rx_desc) {
dev_err(drv_data->ssp->dev, "failed to get DMA RX descriptor\n");
err = -EBUSY;
goto err_rx;
}
/* We are ready when RX completes */
rx_desc->callback = pxa2xx_spi_dma_callback;
rx_desc->callback_param = drv_data;
dmaengine_submit(rx_desc);
dmaengine_submit(tx_desc);
return 0;
err_rx:
dmaengine_terminate_async(drv_data->controller->dma_tx);
err_tx:
return err;
}
void pxa2xx_spi_dma_start(struct driver_data *drv_data)
{
dma_async_issue_pending(drv_data->controller->dma_rx);
dma_async_issue_pending(drv_data->controller->dma_tx);
atomic_set(&drv_data->dma_running, 1);
}
void pxa2xx_spi_dma_stop(struct driver_data *drv_data)
{
atomic_set(&drv_data->dma_running, 0);
dmaengine_terminate_sync(drv_data->controller->dma_rx);
dmaengine_terminate_sync(drv_data->controller->dma_tx);
}
int pxa2xx_spi_dma_setup(struct driver_data *drv_data)
{
struct pxa2xx_spi_controller *pdata = drv_data->controller_info;
struct spi_controller *controller = drv_data->controller;
struct device *dev = drv_data->ssp->dev;
dma_cap_mask_t mask;
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
controller->dma_tx = dma_request_slave_channel_compat(mask,
pdata->dma_filter, pdata->tx_param, dev, "tx");
if (!controller->dma_tx)
return -ENODEV;
controller->dma_rx = dma_request_slave_channel_compat(mask,
pdata->dma_filter, pdata->rx_param, dev, "rx");
if (!controller->dma_rx) {
dma_release_channel(controller->dma_tx);
controller->dma_tx = NULL;
return -ENODEV;
}
return 0;
}
void pxa2xx_spi_dma_release(struct driver_data *drv_data)
{
struct spi_controller *controller = drv_data->controller;
if (controller->dma_rx) {
dmaengine_terminate_sync(controller->dma_rx);
dma_release_channel(controller->dma_rx);
controller->dma_rx = NULL;
}
if (controller->dma_tx) {
dmaengine_terminate_sync(controller->dma_tx);
dma_release_channel(controller->dma_tx);
controller->dma_tx = NULL;
}
}
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