+++ /dev/null
-/*
- * PXA2xx SPI private DMA support.
- *
- * Copyright (C) 2005 Stephen Street / StreetFire Sound Labs
- *
- * 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/delay.h>
-#include <linux/device.h>
-#include <linux/dma-mapping.h>
-#include <linux/pxa2xx_ssp.h>
-#include <linux/spi/spi.h>
-#include <linux/spi/pxa2xx_spi.h>
-
-#include <mach/dma.h>
-#include "spi-pxa2xx.h"
-
-#define DMA_INT_MASK (DCSR_ENDINTR | DCSR_STARTINTR | DCSR_BUSERR)
-#define RESET_DMA_CHANNEL (DCSR_NODESC | DMA_INT_MASK)
-
-bool pxa2xx_spi_dma_is_possible(size_t len)
-{
- /* Try to map dma buffer and do a dma transfer if successful, but
- * only if the length is non-zero and less than MAX_DMA_LEN.
- *
- * Zero-length non-descriptor DMA is illegal on PXA2xx; force use
- * of PIO instead. Care is needed above because the transfer may
- * have have been passed with buffers that are already dma mapped.
- * A zero-length transfer in PIO mode will not try to write/read
- * to/from the buffers
- *
- * REVISIT large transfers are exactly where we most want to be
- * using DMA. If this happens much, split those transfers into
- * multiple DMA segments rather than forcing PIO.
- */
- return len > 0 && len <= MAX_DMA_LEN;
-}
-
-int pxa2xx_spi_map_dma_buffers(struct driver_data *drv_data)
-{
- struct spi_message *msg = drv_data->cur_msg;
- struct device *dev = &msg->spi->dev;
-
- if (!drv_data->cur_chip->enable_dma)
- return 0;
-
- if (msg->is_dma_mapped)
- return drv_data->rx_dma && drv_data->tx_dma;
-
- if (!IS_DMA_ALIGNED(drv_data->rx) || !IS_DMA_ALIGNED(drv_data->tx))
- return 0;
-
- /* Modify setup if rx buffer is null */
- if (drv_data->rx == NULL) {
- *drv_data->null_dma_buf = 0;
- drv_data->rx = drv_data->null_dma_buf;
- drv_data->rx_map_len = 4;
- } else
- drv_data->rx_map_len = drv_data->len;
-
-
- /* Modify setup if tx buffer is null */
- if (drv_data->tx == NULL) {
- *drv_data->null_dma_buf = 0;
- drv_data->tx = drv_data->null_dma_buf;
- drv_data->tx_map_len = 4;
- } else
- drv_data->tx_map_len = drv_data->len;
-
- /* Stream map the tx buffer. Always do DMA_TO_DEVICE first
- * so we flush the cache *before* invalidating it, in case
- * the tx and rx buffers overlap.
- */
- drv_data->tx_dma = dma_map_single(dev, drv_data->tx,
- drv_data->tx_map_len, DMA_TO_DEVICE);
- if (dma_mapping_error(dev, drv_data->tx_dma))
- return 0;
-
- /* Stream map the rx buffer */
- drv_data->rx_dma = dma_map_single(dev, drv_data->rx,
- drv_data->rx_map_len, DMA_FROM_DEVICE);
- if (dma_mapping_error(dev, drv_data->rx_dma)) {
- dma_unmap_single(dev, drv_data->tx_dma,
- drv_data->tx_map_len, DMA_TO_DEVICE);
- return 0;
- }
-
- return 1;
-}
-
-static void pxa2xx_spi_unmap_dma_buffers(struct driver_data *drv_data)
-{
- struct device *dev;
-
- if (!drv_data->dma_mapped)
- return;
-
- if (!drv_data->cur_msg->is_dma_mapped) {
- dev = &drv_data->cur_msg->spi->dev;
- dma_unmap_single(dev, drv_data->rx_dma,
- drv_data->rx_map_len, DMA_FROM_DEVICE);
- dma_unmap_single(dev, drv_data->tx_dma,
- drv_data->tx_map_len, DMA_TO_DEVICE);
- }
-
- drv_data->dma_mapped = 0;
-}
-
-static int wait_ssp_rx_stall(struct driver_data *drv_data)
-{
- unsigned long limit = loops_per_jiffy << 1;
-
- while ((pxa2xx_spi_read(drv_data, SSSR) & SSSR_BSY) && --limit)
- cpu_relax();
-
- return limit;
-}
-
-static int wait_dma_channel_stop(int channel)
-{
- unsigned long limit = loops_per_jiffy << 1;
-
- while (!(DCSR(channel) & DCSR_STOPSTATE) && --limit)
- cpu_relax();
-
- return limit;
-}
-
-static void pxa2xx_spi_dma_error_stop(struct driver_data *drv_data,
- const char *msg)
-{
- /* Stop and reset */
- DCSR(drv_data->rx_channel) = RESET_DMA_CHANNEL;
- DCSR(drv_data->tx_channel) = RESET_DMA_CHANNEL;
- write_SSSR_CS(drv_data, drv_data->clear_sr);
- pxa2xx_spi_write(drv_data, SSCR1,
- pxa2xx_spi_read(drv_data, SSCR1)
- & ~drv_data->dma_cr1);
- if (!pxa25x_ssp_comp(drv_data))
- pxa2xx_spi_write(drv_data, SSTO, 0);
- pxa2xx_spi_flush(drv_data);
- pxa2xx_spi_write(drv_data, SSCR0,
- pxa2xx_spi_read(drv_data, SSCR0) & ~SSCR0_SSE);
-
- pxa2xx_spi_unmap_dma_buffers(drv_data);
-
- dev_err(&drv_data->pdev->dev, "%s\n", msg);
-
- drv_data->cur_msg->state = ERROR_STATE;
- tasklet_schedule(&drv_data->pump_transfers);
-}
-
-static void pxa2xx_spi_dma_transfer_complete(struct driver_data *drv_data)
-{
- struct spi_message *msg = drv_data->cur_msg;
-
- /* Clear and disable interrupts on SSP and DMA channels*/
- pxa2xx_spi_write(drv_data, SSCR1,
- pxa2xx_spi_read(drv_data, SSCR1)
- & ~drv_data->dma_cr1);
- write_SSSR_CS(drv_data, drv_data->clear_sr);
- DCSR(drv_data->tx_channel) = RESET_DMA_CHANNEL;
- DCSR(drv_data->rx_channel) = RESET_DMA_CHANNEL;
-
- if (wait_dma_channel_stop(drv_data->rx_channel) == 0)
- dev_err(&drv_data->pdev->dev,
- "dma_handler: dma rx channel stop failed\n");
-
- if (wait_ssp_rx_stall(drv_data->ioaddr) == 0)
- dev_err(&drv_data->pdev->dev,
- "dma_transfer: ssp rx stall failed\n");
-
- pxa2xx_spi_unmap_dma_buffers(drv_data);
-
- /* update the buffer pointer for the amount completed in dma */
- drv_data->rx += drv_data->len -
- (DCMD(drv_data->rx_channel) & DCMD_LENGTH);
-
- /* read trailing data from fifo, it does not matter how many
- * bytes are in the fifo just read until buffer is full
- * or fifo is empty, which ever occurs first */
- drv_data->read(drv_data);
-
- /* return count of what was actually read */
- msg->actual_length += drv_data->len -
- (drv_data->rx_end - drv_data->rx);
-
- /* Transfer delays and chip select release are
- * handled in pump_transfers or giveback
- */
-
- /* Move to next transfer */
- msg->state = pxa2xx_spi_next_transfer(drv_data);
-
- /* Schedule transfer tasklet */
- tasklet_schedule(&drv_data->pump_transfers);
-}
-
-void pxa2xx_spi_dma_handler(int channel, void *data)
-{
- struct driver_data *drv_data = data;
- u32 irq_status = DCSR(channel) & DMA_INT_MASK;
-
- if (irq_status & DCSR_BUSERR) {
-
- if (channel == drv_data->tx_channel)
- pxa2xx_spi_dma_error_stop(drv_data,
- "dma_handler: bad bus address on tx channel");
- else
- pxa2xx_spi_dma_error_stop(drv_data,
- "dma_handler: bad bus address on rx channel");
- return;
- }
-
- /* PXA255x_SSP has no timeout interrupt, wait for tailing bytes */
- if ((channel == drv_data->tx_channel)
- && (irq_status & DCSR_ENDINTR)
- && (drv_data->ssp_type == PXA25x_SSP)) {
-
- /* Wait for rx to stall */
- if (wait_ssp_rx_stall(drv_data) == 0)
- dev_err(&drv_data->pdev->dev,
- "dma_handler: ssp rx stall failed\n");
-
- /* finish this transfer, start the next */
- pxa2xx_spi_dma_transfer_complete(drv_data);
- }
-}
-
-irqreturn_t pxa2xx_spi_dma_transfer(struct driver_data *drv_data)
-{
- u32 irq_status;
-
- irq_status = pxa2xx_spi_read(drv_data, SSSR) & drv_data->mask_sr;
- if (irq_status & SSSR_ROR) {
- pxa2xx_spi_dma_error_stop(drv_data,
- "dma_transfer: fifo overrun");
- return IRQ_HANDLED;
- }
-
- /* Check for false positive timeout */
- if ((irq_status & SSSR_TINT)
- && (DCSR(drv_data->tx_channel) & DCSR_RUN)) {
- pxa2xx_spi_write(drv_data, SSSR, SSSR_TINT);
- return IRQ_HANDLED;
- }
-
- if (irq_status & SSSR_TINT || drv_data->rx == drv_data->rx_end) {
-
- /* Clear and disable timeout interrupt, do the rest in
- * dma_transfer_complete */
- if (!pxa25x_ssp_comp(drv_data))
- pxa2xx_spi_write(drv_data, SSTO, 0);
-
- /* finish this transfer, start the next */
- pxa2xx_spi_dma_transfer_complete(drv_data);
-
- return IRQ_HANDLED;
- }
-
- /* Opps problem detected */
- return IRQ_NONE;
-}
-
-int pxa2xx_spi_dma_prepare(struct driver_data *drv_data, u32 dma_burst)
-{
- u32 dma_width;
-
- switch (drv_data->n_bytes) {
- case 1:
- dma_width = DCMD_WIDTH1;
- break;
- case 2:
- dma_width = DCMD_WIDTH2;
- break;
- default:
- dma_width = DCMD_WIDTH4;
- break;
- }
-
- /* Setup rx DMA Channel */
- DCSR(drv_data->rx_channel) = RESET_DMA_CHANNEL;
- DSADR(drv_data->rx_channel) = drv_data->ssdr_physical;
- DTADR(drv_data->rx_channel) = drv_data->rx_dma;
- if (drv_data->rx == drv_data->null_dma_buf)
- /* No target address increment */
- DCMD(drv_data->rx_channel) = DCMD_FLOWSRC
- | dma_width
- | dma_burst
- | drv_data->len;
- else
- DCMD(drv_data->rx_channel) = DCMD_INCTRGADDR
- | DCMD_FLOWSRC
- | dma_width
- | dma_burst
- | drv_data->len;
-
- /* Setup tx DMA Channel */
- DCSR(drv_data->tx_channel) = RESET_DMA_CHANNEL;
- DSADR(drv_data->tx_channel) = drv_data->tx_dma;
- DTADR(drv_data->tx_channel) = drv_data->ssdr_physical;
- if (drv_data->tx == drv_data->null_dma_buf)
- /* No source address increment */
- DCMD(drv_data->tx_channel) = DCMD_FLOWTRG
- | dma_width
- | dma_burst
- | drv_data->len;
- else
- DCMD(drv_data->tx_channel) = DCMD_INCSRCADDR
- | DCMD_FLOWTRG
- | dma_width
- | dma_burst
- | drv_data->len;
-
- /* Enable dma end irqs on SSP to detect end of transfer */
- if (drv_data->ssp_type == PXA25x_SSP)
- DCMD(drv_data->tx_channel) |= DCMD_ENDIRQEN;
-
- return 0;
-}
-
-void pxa2xx_spi_dma_start(struct driver_data *drv_data)
-{
- DCSR(drv_data->rx_channel) |= DCSR_RUN;
- DCSR(drv_data->tx_channel) |= DCSR_RUN;
-}
-
-int pxa2xx_spi_dma_setup(struct driver_data *drv_data)
-{
- struct device *dev = &drv_data->pdev->dev;
- struct ssp_device *ssp = drv_data->ssp;
-
- /* Get two DMA channels (rx and tx) */
- drv_data->rx_channel = pxa_request_dma("pxa2xx_spi_ssp_rx",
- DMA_PRIO_HIGH,
- pxa2xx_spi_dma_handler,
- drv_data);
- if (drv_data->rx_channel < 0) {
- dev_err(dev, "problem (%d) requesting rx channel\n",
- drv_data->rx_channel);
- return -ENODEV;
- }
- drv_data->tx_channel = pxa_request_dma("pxa2xx_spi_ssp_tx",
- DMA_PRIO_MEDIUM,
- pxa2xx_spi_dma_handler,
- drv_data);
- if (drv_data->tx_channel < 0) {
- dev_err(dev, "problem (%d) requesting tx channel\n",
- drv_data->tx_channel);
- pxa_free_dma(drv_data->rx_channel);
- return -ENODEV;
- }
-
- DRCMR(ssp->drcmr_rx) = DRCMR_MAPVLD | drv_data->rx_channel;
- DRCMR(ssp->drcmr_tx) = DRCMR_MAPVLD | drv_data->tx_channel;
-
- return 0;
-}
-
-void pxa2xx_spi_dma_release(struct driver_data *drv_data)
-{
- struct ssp_device *ssp = drv_data->ssp;
-
- DRCMR(ssp->drcmr_rx) = 0;
- DRCMR(ssp->drcmr_tx) = 0;
-
- if (drv_data->tx_channel != 0)
- pxa_free_dma(drv_data->tx_channel);
- if (drv_data->rx_channel != 0)
- pxa_free_dma(drv_data->rx_channel);
-}
-
-void pxa2xx_spi_dma_resume(struct driver_data *drv_data)
-{
- if (drv_data->rx_channel != -1)
- DRCMR(drv_data->ssp->drcmr_rx) =
- DRCMR_MAPVLD | drv_data->rx_channel;
- if (drv_data->tx_channel != -1)
- DRCMR(drv_data->ssp->drcmr_tx) =
- DRCMR_MAPVLD | drv_data->tx_channel;
-}
-
-int pxa2xx_spi_set_dma_burst_and_threshold(struct chip_data *chip,
- struct spi_device *spi,
- u8 bits_per_word, u32 *burst_code,
- u32 *threshold)
-{
- struct pxa2xx_spi_chip *chip_info =
- (struct pxa2xx_spi_chip *)spi->controller_data;
- int bytes_per_word;
- int burst_bytes;
- int thresh_words;
- int req_burst_size;
- int retval = 0;
-
- /* Set the threshold (in registers) to equal the same amount of data
- * as represented by burst size (in bytes). The computation below
- * is (burst_size rounded up to nearest 8 byte, word or long word)
- * divided by (bytes/register); the tx threshold is the inverse of
- * the rx, so that there will always be enough data in the rx fifo
- * to satisfy a burst, and there will always be enough space in the
- * tx fifo to accept a burst (a tx burst will overwrite the fifo if
- * there is not enough space), there must always remain enough empty
- * space in the rx fifo for any data loaded to the tx fifo.
- * Whenever burst_size (in bytes) equals bits/word, the fifo threshold
- * will be 8, or half the fifo;
- * The threshold can only be set to 2, 4 or 8, but not 16, because
- * to burst 16 to the tx fifo, the fifo would have to be empty;
- * however, the minimum fifo trigger level is 1, and the tx will
- * request service when the fifo is at this level, with only 15 spaces.
- */
-
- /* find bytes/word */
- if (bits_per_word <= 8)
- bytes_per_word = 1;
- else if (bits_per_word <= 16)
- bytes_per_word = 2;
- else
- bytes_per_word = 4;
-
- /* use struct pxa2xx_spi_chip->dma_burst_size if available */
- if (chip_info)
- req_burst_size = chip_info->dma_burst_size;
- else {
- switch (chip->dma_burst_size) {
- default:
- /* if the default burst size is not set,
- * do it now */
- chip->dma_burst_size = DCMD_BURST8;
- case DCMD_BURST8:
- req_burst_size = 8;
- break;
- case DCMD_BURST16:
- req_burst_size = 16;
- break;
- case DCMD_BURST32:
- req_burst_size = 32;
- break;
- }
- }
- if (req_burst_size <= 8) {
- *burst_code = DCMD_BURST8;
- burst_bytes = 8;
- } else if (req_burst_size <= 16) {
- if (bytes_per_word == 1) {
- /* don't burst more than 1/2 the fifo */
- *burst_code = DCMD_BURST8;
- burst_bytes = 8;
- retval = 1;
- } else {
- *burst_code = DCMD_BURST16;
- burst_bytes = 16;
- }
- } else {
- if (bytes_per_word == 1) {
- /* don't burst more than 1/2 the fifo */
- *burst_code = DCMD_BURST8;
- burst_bytes = 8;
- retval = 1;
- } else if (bytes_per_word == 2) {
- /* don't burst more than 1/2 the fifo */
- *burst_code = DCMD_BURST16;
- burst_bytes = 16;
- retval = 1;
- } else {
- *burst_code = DCMD_BURST32;
- burst_bytes = 32;
- }
- }
-
- thresh_words = burst_bytes / bytes_per_word;
-
- /* thresh_words will be between 2 and 8 */
- *threshold = (SSCR1_RxTresh(thresh_words) & SSCR1_RFT)
- | (SSCR1_TxTresh(16-thresh_words) & SSCR1_TFT);
-
- return retval;
-}
projects / linux-beck.git / commitdiff