diff options
author | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2015-09-08 01:01:14 -0300 |
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committer | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2015-09-08 01:01:14 -0300 |
commit | e5fd91f1ef340da553f7a79da9540c3db711c937 (patch) | |
tree | b11842027dc6641da63f4bcc524f8678263304a3 /drivers/spi/spi-pxa2xx-pxadma.c | |
parent | 2a9b0348e685a63d97486f6749622b61e9e3292f (diff) |
Linux-libre 4.2-gnu
Diffstat (limited to 'drivers/spi/spi-pxa2xx-pxadma.c')
-rw-r--r-- | drivers/spi/spi-pxa2xx-pxadma.c | 487 |
1 files changed, 0 insertions, 487 deletions
diff --git a/drivers/spi/spi-pxa2xx-pxadma.c b/drivers/spi/spi-pxa2xx-pxadma.c deleted file mode 100644 index 2e0796a00..000000000 --- a/drivers/spi/spi-pxa2xx-pxadma.c +++ /dev/null @@ -1,487 +0,0 @@ -/* - * 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; -} |