From de6efe0a966cf86b3c4039a610b2d4157db707f2 Mon Sep 17 00:00:00 2001 From: Feng Tang Date: Wed, 30 Mar 2011 23:09:52 +0800 Subject: [PATCH] spi/dw_spi: unify the low level read/write routines The original version has many duplicated codes for null/u8/u16 case, so unify them to make it cleaner Signed-off-by: Feng Tang Signed-off-by: Grant Likely --- drivers/spi/dw_spi.c | 105 +++++++++++-------------------------------- drivers/spi/dw_spi.h | 2 - 2 files changed, 27 insertions(+), 80 deletions(-) diff --git a/drivers/spi/dw_spi.c b/drivers/spi/dw_spi.c index 9a6196461b27..c4fca3d9d45f 100644 --- a/drivers/spi/dw_spi.c +++ b/drivers/spi/dw_spi.c @@ -58,8 +58,6 @@ struct chip_data { u8 bits_per_word; u16 clk_div; /* baud rate divider */ u32 speed_hz; /* baud rate */ - int (*write)(struct dw_spi *dws); - int (*read)(struct dw_spi *dws); void (*cs_control)(u32 command); }; @@ -185,80 +183,45 @@ static void flush(struct dw_spi *dws) wait_till_not_busy(dws); } -static int null_writer(struct dw_spi *dws) + +static int dw_writer(struct dw_spi *dws) { - u8 n_bytes = dws->n_bytes; + u16 txw = 0; if (!(dw_readw(dws, sr) & SR_TF_NOT_FULL) || (dws->tx == dws->tx_end)) return 0; - dw_writew(dws, dr, 0); - dws->tx += n_bytes; - wait_till_not_busy(dws); - return 1; -} - -static int null_reader(struct dw_spi *dws) -{ - u8 n_bytes = dws->n_bytes; - - while ((dw_readw(dws, sr) & SR_RF_NOT_EMPT) - && (dws->rx < dws->rx_end)) { - dw_readw(dws, dr); - dws->rx += n_bytes; - } - wait_till_not_busy(dws); - return dws->rx == dws->rx_end; -} - -static int u8_writer(struct dw_spi *dws) -{ - if (!(dw_readw(dws, sr) & SR_TF_NOT_FULL) - || (dws->tx == dws->tx_end)) - return 0; - - dw_writew(dws, dr, *(u8 *)(dws->tx)); - ++dws->tx; - - wait_till_not_busy(dws); - return 1; -} - -static int u8_reader(struct dw_spi *dws) -{ - while ((dw_readw(dws, sr) & SR_RF_NOT_EMPT) - && (dws->rx < dws->rx_end)) { - *(u8 *)(dws->rx) = dw_readw(dws, dr); - ++dws->rx; + /* Set the tx word if the transfer's original "tx" is not null */ + if (dws->tx_end - dws->len) { + if (dws->n_bytes == 1) + txw = *(u8 *)(dws->tx); + else + txw = *(u16 *)(dws->tx); } - wait_till_not_busy(dws); - return dws->rx == dws->rx_end; -} - -static int u16_writer(struct dw_spi *dws) -{ - if (!(dw_readw(dws, sr) & SR_TF_NOT_FULL) - || (dws->tx == dws->tx_end)) - return 0; - - dw_writew(dws, dr, *(u16 *)(dws->tx)); - dws->tx += 2; + dw_writew(dws, dr, txw); + dws->tx += dws->n_bytes; wait_till_not_busy(dws); return 1; } -static int u16_reader(struct dw_spi *dws) +static int dw_reader(struct dw_spi *dws) { - u16 temp; + u16 rxw; while ((dw_readw(dws, sr) & SR_RF_NOT_EMPT) && (dws->rx < dws->rx_end)) { - temp = dw_readw(dws, dr); - *(u16 *)(dws->rx) = temp; - dws->rx += 2; + rxw = dw_readw(dws, dr); + /* Care rx only if the transfer's original "rx" is not null */ + if (dws->rx_end - dws->len) { + if (dws->n_bytes == 1) + *(u8 *)(dws->rx) = rxw; + else + *(u16 *)(dws->rx) = rxw; + } + dws->rx += dws->n_bytes; } wait_till_not_busy(dws); @@ -383,8 +346,8 @@ static irqreturn_t interrupt_transfer(struct dw_spi *dws) left = (left > int_level) ? int_level : left; while (left--) - dws->write(dws); - dws->read(dws); + dw_writer(dws); + dw_reader(dws); /* Re-enable the IRQ if there is still data left to tx */ if (dws->tx_end > dws->tx) @@ -417,13 +380,13 @@ static irqreturn_t dw_spi_irq(int irq, void *dev_id) /* Must be called inside pump_transfers() */ static void poll_transfer(struct dw_spi *dws) { - while (dws->write(dws)) - dws->read(dws); + while (dw_writer(dws)) + dw_reader(dws); /* * There is a possibility that the last word of a transaction * will be lost if data is not ready. Re-read to solve this issue. */ - dws->read(dws); + dw_reader(dws); dw_spi_xfer_done(dws); } @@ -483,8 +446,6 @@ static void pump_transfers(unsigned long data) dws->tx_end = dws->tx + transfer->len; dws->rx = transfer->rx_buf; dws->rx_end = dws->rx + transfer->len; - dws->write = dws->tx ? chip->write : null_writer; - dws->read = dws->rx ? chip->read : null_reader; dws->cs_change = transfer->cs_change; dws->len = dws->cur_transfer->len; if (chip != dws->prev_chip) @@ -520,18 +481,10 @@ static void pump_transfers(unsigned long data) case 8: dws->n_bytes = 1; dws->dma_width = 1; - dws->read = (dws->read != null_reader) ? - u8_reader : null_reader; - dws->write = (dws->write != null_writer) ? - u8_writer : null_writer; break; case 16: dws->n_bytes = 2; dws->dma_width = 2; - dws->read = (dws->read != null_reader) ? - u16_reader : null_reader; - dws->write = (dws->write != null_writer) ? - u16_writer : null_writer; break; default: printk(KERN_ERR "MRST SPI0: unsupported bits:" @@ -733,13 +686,9 @@ static int dw_spi_setup(struct spi_device *spi) if (spi->bits_per_word <= 8) { chip->n_bytes = 1; chip->dma_width = 1; - chip->read = u8_reader; - chip->write = u8_writer; } else if (spi->bits_per_word <= 16) { chip->n_bytes = 2; chip->dma_width = 2; - chip->read = u16_reader; - chip->write = u16_writer; } else { /* Never take >16b case for MRST SPIC */ dev_err(&spi->dev, "invalid wordsize\n"); diff --git a/drivers/spi/dw_spi.h b/drivers/spi/dw_spi.h index fb0bce564844..d8aac1f4c546 100644 --- a/drivers/spi/dw_spi.h +++ b/drivers/spi/dw_spi.h @@ -137,8 +137,6 @@ struct dw_spi { u8 max_bits_per_word; /* maxim is 16b */ u32 dma_width; int cs_change; - int (*write)(struct dw_spi *dws); - int (*read)(struct dw_spi *dws); irqreturn_t (*transfer_handler)(struct dw_spi *dws); void (*cs_control)(u32 command);