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a928a36ff9
The chipselect must be written into the CTRL0 register after the SSP block is reset, otherwise the block will always use ChipSelect #0. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Fabio Estevam <fabio.estevam@freescale.com> Cc: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com> Cc: Otavio Salvador <otavio@ossystems.com.br> Cc: Stefano Babic <sbabic@denx.de> Acked-by: Stefano Babic <sbabic@denx.de>
362 lines
8.7 KiB
C
362 lines
8.7 KiB
C
/*
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* Freescale i.MX28 SPI driver
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*
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* Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
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* on behalf of DENX Software Engineering GmbH
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*
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* SPDX-License-Identifier: GPL-2.0+
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*
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* NOTE: This driver only supports the SPI-controller chipselects,
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* GPIO driven chipselects are not supported.
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*/
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#include <common.h>
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#include <malloc.h>
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#include <spi.h>
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#include <asm/errno.h>
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#include <asm/io.h>
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#include <asm/arch/clock.h>
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#include <asm/arch/imx-regs.h>
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#include <asm/arch/sys_proto.h>
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#include <asm/imx-common/dma.h>
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#define MXS_SPI_MAX_TIMEOUT 1000000
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#define MXS_SPI_PORT_OFFSET 0x2000
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#define MXS_SSP_CHIPSELECT_MASK 0x00300000
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#define MXS_SSP_CHIPSELECT_SHIFT 20
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#define MXSSSP_SMALL_TRANSFER 512
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struct mxs_spi_slave {
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struct spi_slave slave;
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uint32_t max_khz;
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uint32_t mode;
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struct mxs_ssp_regs *regs;
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};
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static inline struct mxs_spi_slave *to_mxs_slave(struct spi_slave *slave)
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{
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return container_of(slave, struct mxs_spi_slave, slave);
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}
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void spi_init(void)
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{
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}
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int spi_cs_is_valid(unsigned int bus, unsigned int cs)
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{
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/* MXS SPI: 4 ports and 3 chip selects maximum */
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if (!mxs_ssp_bus_id_valid(bus) || cs > 2)
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return 0;
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else
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return 1;
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}
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struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
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unsigned int max_hz, unsigned int mode)
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{
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struct mxs_spi_slave *mxs_slave;
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if (!spi_cs_is_valid(bus, cs)) {
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printf("mxs_spi: invalid bus %d / chip select %d\n", bus, cs);
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return NULL;
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}
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mxs_slave = spi_alloc_slave(struct mxs_spi_slave, bus, cs);
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if (!mxs_slave)
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return NULL;
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if (mxs_dma_init_channel(MXS_DMA_CHANNEL_AHB_APBH_SSP0 + bus))
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goto err_init;
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mxs_slave->max_khz = max_hz / 1000;
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mxs_slave->mode = mode;
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mxs_slave->regs = mxs_ssp_regs_by_bus(bus);
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return &mxs_slave->slave;
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err_init:
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free(mxs_slave);
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return NULL;
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}
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void spi_free_slave(struct spi_slave *slave)
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{
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struct mxs_spi_slave *mxs_slave = to_mxs_slave(slave);
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free(mxs_slave);
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}
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int spi_claim_bus(struct spi_slave *slave)
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{
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struct mxs_spi_slave *mxs_slave = to_mxs_slave(slave);
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struct mxs_ssp_regs *ssp_regs = mxs_slave->regs;
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uint32_t reg = 0;
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mxs_reset_block(&ssp_regs->hw_ssp_ctrl0_reg);
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writel((slave->cs << MXS_SSP_CHIPSELECT_SHIFT) |
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SSP_CTRL0_BUS_WIDTH_ONE_BIT,
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&ssp_regs->hw_ssp_ctrl0);
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reg = SSP_CTRL1_SSP_MODE_SPI | SSP_CTRL1_WORD_LENGTH_EIGHT_BITS;
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reg |= (mxs_slave->mode & SPI_CPOL) ? SSP_CTRL1_POLARITY : 0;
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reg |= (mxs_slave->mode & SPI_CPHA) ? SSP_CTRL1_PHASE : 0;
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writel(reg, &ssp_regs->hw_ssp_ctrl1);
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writel(0, &ssp_regs->hw_ssp_cmd0);
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mxs_set_ssp_busclock(slave->bus, mxs_slave->max_khz);
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return 0;
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}
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void spi_release_bus(struct spi_slave *slave)
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{
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}
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static void mxs_spi_start_xfer(struct mxs_ssp_regs *ssp_regs)
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{
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writel(SSP_CTRL0_LOCK_CS, &ssp_regs->hw_ssp_ctrl0_set);
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writel(SSP_CTRL0_IGNORE_CRC, &ssp_regs->hw_ssp_ctrl0_clr);
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}
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static void mxs_spi_end_xfer(struct mxs_ssp_regs *ssp_regs)
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{
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writel(SSP_CTRL0_LOCK_CS, &ssp_regs->hw_ssp_ctrl0_clr);
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writel(SSP_CTRL0_IGNORE_CRC, &ssp_regs->hw_ssp_ctrl0_set);
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}
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static int mxs_spi_xfer_pio(struct mxs_spi_slave *slave,
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char *data, int length, int write, unsigned long flags)
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{
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struct mxs_ssp_regs *ssp_regs = slave->regs;
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if (flags & SPI_XFER_BEGIN)
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mxs_spi_start_xfer(ssp_regs);
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while (length--) {
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/* We transfer 1 byte */
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#if defined(CONFIG_MX23)
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writel(SSP_CTRL0_XFER_COUNT_MASK, &ssp_regs->hw_ssp_ctrl0_clr);
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writel(1, &ssp_regs->hw_ssp_ctrl0_set);
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#elif defined(CONFIG_MX28)
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writel(1, &ssp_regs->hw_ssp_xfer_size);
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#endif
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if ((flags & SPI_XFER_END) && !length)
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mxs_spi_end_xfer(ssp_regs);
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if (write)
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writel(SSP_CTRL0_READ, &ssp_regs->hw_ssp_ctrl0_clr);
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else
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writel(SSP_CTRL0_READ, &ssp_regs->hw_ssp_ctrl0_set);
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writel(SSP_CTRL0_RUN, &ssp_regs->hw_ssp_ctrl0_set);
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if (mxs_wait_mask_set(&ssp_regs->hw_ssp_ctrl0_reg,
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SSP_CTRL0_RUN, MXS_SPI_MAX_TIMEOUT)) {
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printf("MXS SPI: Timeout waiting for start\n");
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return -ETIMEDOUT;
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}
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if (write)
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writel(*data++, &ssp_regs->hw_ssp_data);
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writel(SSP_CTRL0_DATA_XFER, &ssp_regs->hw_ssp_ctrl0_set);
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if (!write) {
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if (mxs_wait_mask_clr(&ssp_regs->hw_ssp_status_reg,
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SSP_STATUS_FIFO_EMPTY, MXS_SPI_MAX_TIMEOUT)) {
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printf("MXS SPI: Timeout waiting for data\n");
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return -ETIMEDOUT;
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}
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*data = readl(&ssp_regs->hw_ssp_data);
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data++;
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}
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if (mxs_wait_mask_clr(&ssp_regs->hw_ssp_ctrl0_reg,
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SSP_CTRL0_RUN, MXS_SPI_MAX_TIMEOUT)) {
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printf("MXS SPI: Timeout waiting for finish\n");
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return -ETIMEDOUT;
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}
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}
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return 0;
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}
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static int mxs_spi_xfer_dma(struct mxs_spi_slave *slave,
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char *data, int length, int write, unsigned long flags)
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{
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const int xfer_max_sz = 0xff00;
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const int desc_count = DIV_ROUND_UP(length, xfer_max_sz) + 1;
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struct mxs_ssp_regs *ssp_regs = slave->regs;
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struct mxs_dma_desc *dp;
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uint32_t ctrl0;
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uint32_t cache_data_count;
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const uint32_t dstart = (uint32_t)data;
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int dmach;
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int tl;
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int ret = 0;
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#if defined(CONFIG_MX23)
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const int mxs_spi_pio_words = 1;
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#elif defined(CONFIG_MX28)
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const int mxs_spi_pio_words = 4;
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#endif
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ALLOC_CACHE_ALIGN_BUFFER(struct mxs_dma_desc, desc, desc_count);
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memset(desc, 0, sizeof(struct mxs_dma_desc) * desc_count);
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ctrl0 = readl(&ssp_regs->hw_ssp_ctrl0);
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ctrl0 |= SSP_CTRL0_DATA_XFER;
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if (flags & SPI_XFER_BEGIN)
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ctrl0 |= SSP_CTRL0_LOCK_CS;
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if (!write)
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ctrl0 |= SSP_CTRL0_READ;
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if (length % ARCH_DMA_MINALIGN)
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cache_data_count = roundup(length, ARCH_DMA_MINALIGN);
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else
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cache_data_count = length;
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/* Flush data to DRAM so DMA can pick them up */
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if (write)
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flush_dcache_range(dstart, dstart + cache_data_count);
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/* Invalidate the area, so no writeback into the RAM races with DMA */
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invalidate_dcache_range(dstart, dstart + cache_data_count);
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dmach = MXS_DMA_CHANNEL_AHB_APBH_SSP0 + slave->slave.bus;
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dp = desc;
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while (length) {
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dp->address = (dma_addr_t)dp;
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dp->cmd.address = (dma_addr_t)data;
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/*
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* This is correct, even though it does indeed look insane.
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* I hereby have to, wholeheartedly, thank Freescale Inc.,
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* for always inventing insane hardware and keeping me busy
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* and employed ;-)
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*/
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if (write)
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dp->cmd.data = MXS_DMA_DESC_COMMAND_DMA_READ;
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else
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dp->cmd.data = MXS_DMA_DESC_COMMAND_DMA_WRITE;
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/*
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* The DMA controller can transfer large chunks (64kB) at
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* time by setting the transfer length to 0. Setting tl to
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* 0x10000 will overflow below and make .data contain 0.
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* Otherwise, 0xff00 is the transfer maximum.
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*/
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if (length >= 0x10000)
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tl = 0x10000;
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else
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tl = min(length, xfer_max_sz);
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dp->cmd.data |=
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((tl & 0xffff) << MXS_DMA_DESC_BYTES_OFFSET) |
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(mxs_spi_pio_words << MXS_DMA_DESC_PIO_WORDS_OFFSET) |
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MXS_DMA_DESC_HALT_ON_TERMINATE |
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MXS_DMA_DESC_TERMINATE_FLUSH;
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data += tl;
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length -= tl;
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if (!length) {
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dp->cmd.data |= MXS_DMA_DESC_IRQ | MXS_DMA_DESC_DEC_SEM;
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if (flags & SPI_XFER_END) {
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ctrl0 &= ~SSP_CTRL0_LOCK_CS;
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ctrl0 |= SSP_CTRL0_IGNORE_CRC;
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}
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}
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/*
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* Write CTRL0, CMD0, CMD1 and XFER_SIZE registers in
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* case of MX28, write only CTRL0 in case of MX23 due
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* to the difference in register layout. It is utterly
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* essential that the XFER_SIZE register is written on
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* a per-descriptor basis with the same size as is the
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* descriptor!
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*/
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dp->cmd.pio_words[0] = ctrl0;
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#ifdef CONFIG_MX28
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dp->cmd.pio_words[1] = 0;
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dp->cmd.pio_words[2] = 0;
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dp->cmd.pio_words[3] = tl;
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#endif
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mxs_dma_desc_append(dmach, dp);
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dp++;
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}
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if (mxs_dma_go(dmach))
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ret = -EINVAL;
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/* The data arrived into DRAM, invalidate cache over them */
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if (!write)
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invalidate_dcache_range(dstart, dstart + cache_data_count);
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return ret;
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}
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int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
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const void *dout, void *din, unsigned long flags)
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{
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struct mxs_spi_slave *mxs_slave = to_mxs_slave(slave);
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struct mxs_ssp_regs *ssp_regs = mxs_slave->regs;
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int len = bitlen / 8;
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char dummy;
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int write = 0;
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char *data = NULL;
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int dma = 1;
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if (bitlen == 0) {
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if (flags & SPI_XFER_END) {
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din = (void *)&dummy;
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len = 1;
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} else
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return 0;
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}
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/* Half-duplex only */
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if (din && dout)
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return -EINVAL;
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/* No data */
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if (!din && !dout)
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return 0;
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if (dout) {
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data = (char *)dout;
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write = 1;
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} else if (din) {
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data = (char *)din;
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write = 0;
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}
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/*
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* Check for alignment, if the buffer is aligned, do DMA transfer,
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* PIO otherwise. This is a temporary workaround until proper bounce
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* buffer is in place.
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*/
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if (dma) {
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if (((uint32_t)data) & (ARCH_DMA_MINALIGN - 1))
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dma = 0;
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if (((uint32_t)len) & (ARCH_DMA_MINALIGN - 1))
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dma = 0;
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}
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if (!dma || (len < MXSSSP_SMALL_TRANSFER)) {
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writel(SSP_CTRL1_DMA_ENABLE, &ssp_regs->hw_ssp_ctrl1_clr);
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return mxs_spi_xfer_pio(mxs_slave, data, len, write, flags);
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} else {
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writel(SSP_CTRL1_DMA_ENABLE, &ssp_regs->hw_ssp_ctrl1_set);
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return mxs_spi_xfer_dma(mxs_slave, data, len, write, flags);
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}
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}
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