254 lines
6.4 KiB
C
254 lines
6.4 KiB
C
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/*
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* PXA2xx SPI DMA engine support.
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*
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* Copyright (C) 2013, Intel Corporation
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* Author: Mika Westerberg <mika.westerberg@linux.intel.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/device.h>
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#include <linux/dma-mapping.h>
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#include <linux/dmaengine.h>
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#include <linux/pxa2xx_ssp.h>
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#include <linux/scatterlist.h>
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#include <linux/sizes.h>
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#include <linux/spi/spi.h>
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#include <linux/spi/pxa2xx_spi.h>
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#include "spi-pxa2xx.h"
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static void pxa2xx_spi_dma_transfer_complete(struct driver_data *drv_data,
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bool error)
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{
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struct spi_message *msg = drv_data->master->cur_msg;
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/*
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* It is possible that one CPU is handling ROR interrupt and other
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* just gets DMA completion. Calling pump_transfers() twice for the
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* same transfer leads to problems thus we prevent concurrent calls
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* by using ->dma_running.
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*/
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if (atomic_dec_and_test(&drv_data->dma_running)) {
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/*
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* If the other CPU is still handling the ROR interrupt we
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* might not know about the error yet. So we re-check the
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* ROR bit here before we clear the status register.
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*/
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if (!error) {
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u32 status = pxa2xx_spi_read(drv_data, SSSR)
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& drv_data->mask_sr;
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error = status & SSSR_ROR;
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}
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/* Clear status & disable interrupts */
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pxa2xx_spi_write(drv_data, SSCR1,
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pxa2xx_spi_read(drv_data, SSCR1)
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& ~drv_data->dma_cr1);
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write_SSSR_CS(drv_data, drv_data->clear_sr);
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if (!pxa25x_ssp_comp(drv_data))
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pxa2xx_spi_write(drv_data, SSTO, 0);
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if (error) {
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/* In case we got an error we disable the SSP now */
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pxa2xx_spi_write(drv_data, SSCR0,
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pxa2xx_spi_read(drv_data, SSCR0)
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& ~SSCR0_SSE);
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msg->status = -EIO;
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}
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spi_finalize_current_transfer(drv_data->master);
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}
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}
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static void pxa2xx_spi_dma_callback(void *data)
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{
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pxa2xx_spi_dma_transfer_complete(data, false);
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}
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static struct dma_async_tx_descriptor *
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pxa2xx_spi_dma_prepare_one(struct driver_data *drv_data,
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enum dma_transfer_direction dir,
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struct spi_transfer *xfer)
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{
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struct chip_data *chip =
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spi_get_ctldata(drv_data->master->cur_msg->spi);
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enum dma_slave_buswidth width;
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struct dma_slave_config cfg;
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struct dma_chan *chan;
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struct sg_table *sgt;
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int ret;
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switch (drv_data->n_bytes) {
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case 1:
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width = DMA_SLAVE_BUSWIDTH_1_BYTE;
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break;
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case 2:
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width = DMA_SLAVE_BUSWIDTH_2_BYTES;
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break;
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default:
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width = DMA_SLAVE_BUSWIDTH_4_BYTES;
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break;
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}
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memset(&cfg, 0, sizeof(cfg));
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cfg.direction = dir;
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if (dir == DMA_MEM_TO_DEV) {
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cfg.dst_addr = drv_data->ssdr_physical;
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cfg.dst_addr_width = width;
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cfg.dst_maxburst = chip->dma_burst_size;
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sgt = &xfer->tx_sg;
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chan = drv_data->master->dma_tx;
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} else {
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cfg.src_addr = drv_data->ssdr_physical;
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cfg.src_addr_width = width;
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cfg.src_maxburst = chip->dma_burst_size;
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sgt = &xfer->rx_sg;
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chan = drv_data->master->dma_rx;
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}
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ret = dmaengine_slave_config(chan, &cfg);
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if (ret) {
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dev_warn(&drv_data->pdev->dev, "DMA slave config failed\n");
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return NULL;
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}
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return dmaengine_prep_slave_sg(chan, sgt->sgl, sgt->nents, dir,
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DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
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}
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irqreturn_t pxa2xx_spi_dma_transfer(struct driver_data *drv_data)
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{
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u32 status;
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status = pxa2xx_spi_read(drv_data, SSSR) & drv_data->mask_sr;
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if (status & SSSR_ROR) {
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dev_err(&drv_data->pdev->dev, "FIFO overrun\n");
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dmaengine_terminate_async(drv_data->master->dma_rx);
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dmaengine_terminate_async(drv_data->master->dma_tx);
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pxa2xx_spi_dma_transfer_complete(drv_data, true);
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return IRQ_HANDLED;
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}
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return IRQ_NONE;
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}
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int pxa2xx_spi_dma_prepare(struct driver_data *drv_data,
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struct spi_transfer *xfer)
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{
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struct dma_async_tx_descriptor *tx_desc, *rx_desc;
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int err;
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tx_desc = pxa2xx_spi_dma_prepare_one(drv_data, DMA_MEM_TO_DEV, xfer);
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if (!tx_desc) {
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dev_err(&drv_data->pdev->dev,
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"failed to get DMA TX descriptor\n");
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err = -EBUSY;
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goto err_tx;
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}
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rx_desc = pxa2xx_spi_dma_prepare_one(drv_data, DMA_DEV_TO_MEM, xfer);
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if (!rx_desc) {
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dev_err(&drv_data->pdev->dev,
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"failed to get DMA RX descriptor\n");
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err = -EBUSY;
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goto err_rx;
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}
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/* We are ready when RX completes */
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rx_desc->callback = pxa2xx_spi_dma_callback;
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rx_desc->callback_param = drv_data;
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dmaengine_submit(rx_desc);
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dmaengine_submit(tx_desc);
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return 0;
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err_rx:
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dmaengine_terminate_async(drv_data->master->dma_tx);
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err_tx:
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return err;
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}
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void pxa2xx_spi_dma_start(struct driver_data *drv_data)
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{
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dma_async_issue_pending(drv_data->master->dma_rx);
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dma_async_issue_pending(drv_data->master->dma_tx);
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atomic_set(&drv_data->dma_running, 1);
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}
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void pxa2xx_spi_dma_stop(struct driver_data *drv_data)
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{
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atomic_set(&drv_data->dma_running, 0);
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dmaengine_terminate_sync(drv_data->master->dma_rx);
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dmaengine_terminate_sync(drv_data->master->dma_tx);
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}
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int pxa2xx_spi_dma_setup(struct driver_data *drv_data)
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{
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struct pxa2xx_spi_master *pdata = drv_data->master_info;
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struct device *dev = &drv_data->pdev->dev;
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struct spi_controller *master = drv_data->master;
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dma_cap_mask_t mask;
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dma_cap_zero(mask);
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dma_cap_set(DMA_SLAVE, mask);
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master->dma_tx = dma_request_slave_channel_compat(mask,
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pdata->dma_filter, pdata->tx_param, dev, "tx");
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if (!master->dma_tx)
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return -ENODEV;
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master->dma_rx = dma_request_slave_channel_compat(mask,
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pdata->dma_filter, pdata->rx_param, dev, "rx");
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if (!master->dma_rx) {
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dma_release_channel(master->dma_tx);
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master->dma_tx = NULL;
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return -ENODEV;
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}
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return 0;
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}
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void pxa2xx_spi_dma_release(struct driver_data *drv_data)
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{
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struct spi_controller *master = drv_data->master;
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if (master->dma_rx) {
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dmaengine_terminate_sync(master->dma_rx);
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dma_release_channel(master->dma_rx);
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master->dma_rx = NULL;
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}
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if (master->dma_tx) {
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dmaengine_terminate_sync(master->dma_tx);
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dma_release_channel(master->dma_tx);
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master->dma_tx = NULL;
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}
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}
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int pxa2xx_spi_set_dma_burst_and_threshold(struct chip_data *chip,
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struct spi_device *spi,
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u8 bits_per_word, u32 *burst_code,
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u32 *threshold)
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{
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struct pxa2xx_spi_chip *chip_info = spi->controller_data;
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/*
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* If the DMA burst size is given in chip_info we use that,
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* otherwise we use the default. Also we use the default FIFO
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* thresholds for now.
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*/
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*burst_code = chip_info ? chip_info->dma_burst_size : 1;
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*threshold = SSCR1_RxTresh(RX_THRESH_DFLT)
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| SSCR1_TxTresh(TX_THRESH_DFLT);
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return 0;
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}
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