diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-rspi.c | 320 |
1 files changed, 314 insertions, 6 deletions
diff --git a/drivers/spi/spi-rspi.c b/drivers/spi/spi-rspi.c index 354f170eab95..4894bde4bbff 100644 --- a/drivers/spi/spi-rspi.c +++ b/drivers/spi/spi-rspi.c @@ -31,7 +31,11 @@ #include <linux/platform_device.h> #include <linux/io.h> #include <linux/clk.h> +#include <linux/dmaengine.h> +#include <linux/dma-mapping.h> +#include <linux/sh_dma.h> #include <linux/spi/spi.h> +#include <linux/spi/rspi.h> #define RSPI_SPCR 0x00 #define RSPI_SSLP 0x01 @@ -141,6 +145,16 @@ struct rspi_data { spinlock_t lock; struct clk *clk; unsigned char spsr; + + /* for dmaengine */ + struct sh_dmae_slave dma_tx; + struct sh_dmae_slave dma_rx; + struct dma_chan *chan_tx; + struct dma_chan *chan_rx; + int irq; + + unsigned dma_width_16bit:1; + unsigned dma_callbacked:1; }; static void rspi_write8(struct rspi_data *rspi, u8 data, u16 offset) @@ -265,11 +279,125 @@ static int rspi_send_pio(struct rspi_data *rspi, struct spi_message *mesg, return 0; } -static int rspi_receive_pio(struct rspi_data *rspi, struct spi_message *mesg, - struct spi_transfer *t) +static void rspi_dma_complete(void *arg) +{ + struct rspi_data *rspi = arg; + + rspi->dma_callbacked = 1; + wake_up_interruptible(&rspi->wait); +} + +static int rspi_dma_map_sg(struct scatterlist *sg, void *buf, unsigned len, + struct dma_chan *chan, + enum dma_transfer_direction dir) +{ + sg_init_table(sg, 1); + sg_set_buf(sg, buf, len); + sg_dma_len(sg) = len; + return dma_map_sg(chan->device->dev, sg, 1, dir); +} + +static void rspi_dma_unmap_sg(struct scatterlist *sg, struct dma_chan *chan, + enum dma_transfer_direction dir) +{ + dma_unmap_sg(chan->device->dev, sg, 1, dir); +} + +static void rspi_memory_to_8bit(void *buf, const void *data, unsigned len) +{ + u16 *dst = buf; + const u8 *src = data; + + while (len) { + *dst++ = (u16)(*src++); + len--; + } +} + +static void rspi_memory_from_8bit(void *buf, const void *data, unsigned len) +{ + u8 *dst = buf; + const u16 *src = data; + + while (len) { + *dst++ = (u8)*src++; + len--; + } +} + +static int rspi_send_dma(struct rspi_data *rspi, struct spi_transfer *t) +{ + struct scatterlist sg; + void *buf = NULL; + struct dma_async_tx_descriptor *desc; + unsigned len; + int ret = 0; + + if (rspi->dma_width_16bit) { + /* + * If DMAC bus width is 16-bit, the driver allocates a dummy + * buffer. And, the driver converts original data into the + * DMAC data as the following format: + * original data: 1st byte, 2nd byte ... + * DMAC data: 1st byte, dummy, 2nd byte, dummy ... + */ + len = t->len * 2; + buf = kmalloc(len, GFP_KERNEL); + if (!buf) + return -ENOMEM; + rspi_memory_to_8bit(buf, t->tx_buf, t->len); + } else { + len = t->len; + buf = (void *)t->tx_buf; + } + + if (!rspi_dma_map_sg(&sg, buf, len, rspi->chan_tx, DMA_TO_DEVICE)) { + ret = -EFAULT; + goto end_nomap; + } + desc = dmaengine_prep_slave_sg(rspi->chan_tx, &sg, 1, DMA_TO_DEVICE, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc) { + ret = -EIO; + goto end; + } + + /* + * DMAC needs SPTIE, but if SPTIE is set, this IRQ routine will be + * called. So, this driver disables the IRQ while DMA transfer. + */ + disable_irq(rspi->irq); + + rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) | SPCR_TXMD, RSPI_SPCR); + rspi_enable_irq(rspi, SPCR_SPTIE); + rspi->dma_callbacked = 0; + + desc->callback = rspi_dma_complete; + desc->callback_param = rspi; + dmaengine_submit(desc); + dma_async_issue_pending(rspi->chan_tx); + + ret = wait_event_interruptible_timeout(rspi->wait, + rspi->dma_callbacked, HZ); + if (ret > 0 && rspi->dma_callbacked) + ret = 0; + else if (!ret) + ret = -ETIMEDOUT; + rspi_disable_irq(rspi, SPCR_SPTIE); + + enable_irq(rspi->irq); + +end: + rspi_dma_unmap_sg(&sg, rspi->chan_tx, DMA_TO_DEVICE); +end_nomap: + if (rspi->dma_width_16bit) + kfree(buf); + + return ret; +} + +static void rspi_receive_init(struct rspi_data *rspi) { - int remain = t->len; - u8 *data; unsigned char spsr; spsr = rspi_read8(rspi, RSPI_SPSR); @@ -278,6 +406,15 @@ static int rspi_receive_pio(struct rspi_data *rspi, struct spi_message *mesg, if (spsr & SPSR_OVRF) rspi_write8(rspi, rspi_read8(rspi, RSPI_SPSR) & ~SPSR_OVRF, RSPI_SPCR); +} + +static int rspi_receive_pio(struct rspi_data *rspi, struct spi_message *mesg, + struct spi_transfer *t) +{ + int remain = t->len; + u8 *data; + + rspi_receive_init(rspi); data = (u8 *)t->rx_buf; while (remain > 0) { @@ -307,6 +444,120 @@ static int rspi_receive_pio(struct rspi_data *rspi, struct spi_message *mesg, return 0; } +static int rspi_receive_dma(struct rspi_data *rspi, struct spi_transfer *t) +{ + struct scatterlist sg, sg_dummy; + void *dummy = NULL, *rx_buf = NULL; + struct dma_async_tx_descriptor *desc, *desc_dummy; + unsigned len; + int ret = 0; + + if (rspi->dma_width_16bit) { + /* + * If DMAC bus width is 16-bit, the driver allocates a dummy + * buffer. And, finally the driver converts the DMAC data into + * actual data as the following format: + * DMAC data: 1st byte, dummy, 2nd byte, dummy ... + * actual data: 1st byte, 2nd byte ... + */ + len = t->len * 2; + rx_buf = kmalloc(len, GFP_KERNEL); + if (!rx_buf) + return -ENOMEM; + } else { + len = t->len; + rx_buf = t->rx_buf; + } + + /* prepare dummy transfer to generate SPI clocks */ + dummy = kzalloc(len, GFP_KERNEL); + if (!dummy) { + ret = -ENOMEM; + goto end_nomap; + } + if (!rspi_dma_map_sg(&sg_dummy, dummy, len, rspi->chan_tx, + DMA_TO_DEVICE)) { + ret = -EFAULT; + goto end_nomap; + } + desc_dummy = dmaengine_prep_slave_sg(rspi->chan_tx, &sg_dummy, 1, + DMA_TO_DEVICE, DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc_dummy) { + ret = -EIO; + goto end_dummy_mapped; + } + + /* prepare receive transfer */ + if (!rspi_dma_map_sg(&sg, rx_buf, len, rspi->chan_rx, + DMA_FROM_DEVICE)) { + ret = -EFAULT; + goto end_dummy_mapped; + + } + desc = dmaengine_prep_slave_sg(rspi->chan_rx, &sg, 1, DMA_FROM_DEVICE, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc) { + ret = -EIO; + goto end; + } + + rspi_receive_init(rspi); + + /* + * DMAC needs SPTIE, but if SPTIE is set, this IRQ routine will be + * called. So, this driver disables the IRQ while DMA transfer. + */ + disable_irq(rspi->irq); + + rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) & ~SPCR_TXMD, RSPI_SPCR); + rspi_enable_irq(rspi, SPCR_SPTIE | SPCR_SPRIE); + rspi->dma_callbacked = 0; + + desc->callback = rspi_dma_complete; + desc->callback_param = rspi; + dmaengine_submit(desc); + dma_async_issue_pending(rspi->chan_rx); + + desc_dummy->callback = NULL; /* No callback */ + dmaengine_submit(desc_dummy); + dma_async_issue_pending(rspi->chan_tx); + + ret = wait_event_interruptible_timeout(rspi->wait, + rspi->dma_callbacked, HZ); + if (ret > 0 && rspi->dma_callbacked) + ret = 0; + else if (!ret) + ret = -ETIMEDOUT; + rspi_disable_irq(rspi, SPCR_SPTIE | SPCR_SPRIE); + + enable_irq(rspi->irq); + +end: + rspi_dma_unmap_sg(&sg, rspi->chan_rx, DMA_FROM_DEVICE); +end_dummy_mapped: + rspi_dma_unmap_sg(&sg_dummy, rspi->chan_tx, DMA_TO_DEVICE); +end_nomap: + if (rspi->dma_width_16bit) { + if (!ret) + rspi_memory_from_8bit(t->rx_buf, rx_buf, t->len); + kfree(rx_buf); + } + kfree(dummy); + + return ret; +} + +static int rspi_is_dma(struct rspi_data *rspi, struct spi_transfer *t) +{ + if (t->tx_buf && rspi->chan_tx) + return 1; + /* If the module receives data by DMAC, it also needs TX DMAC */ + if (t->rx_buf && rspi->chan_tx && rspi->chan_rx) + return 1; + + return 0; +} + static void rspi_work(struct work_struct *work) { struct rspi_data *rspi = container_of(work, struct rspi_data, ws); @@ -325,12 +576,18 @@ static void rspi_work(struct work_struct *work) list_for_each_entry(t, &mesg->transfers, transfer_list) { if (t->tx_buf) { - ret = rspi_send_pio(rspi, mesg, t); + if (rspi_is_dma(rspi, t)) + ret = rspi_send_dma(rspi, t); + else + ret = rspi_send_pio(rspi, mesg, t); if (ret < 0) goto error; } if (t->rx_buf) { - ret = rspi_receive_pio(rspi, mesg, t); + if (rspi_is_dma(rspi, t)) + ret = rspi_receive_dma(rspi, t); + else + ret = rspi_receive_pio(rspi, mesg, t); if (ret < 0) goto error; } @@ -406,11 +663,58 @@ static irqreturn_t rspi_irq(int irq, void *_sr) return ret; } +static bool rspi_filter(struct dma_chan *chan, void *filter_param) +{ + chan->private = filter_param; + return true; +} + +static void __devinit rspi_request_dma(struct rspi_data *rspi, + struct platform_device *pdev) +{ + struct rspi_plat_data *rspi_pd = pdev->dev.platform_data; + dma_cap_mask_t mask; + + if (!rspi_pd) + return; + + rspi->dma_width_16bit = rspi_pd->dma_width_16bit; + + /* If the module receives data by DMAC, it also needs TX DMAC */ + if (rspi_pd->dma_rx_id && rspi_pd->dma_tx_id) { + dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + rspi->dma_rx.slave_id = rspi_pd->dma_rx_id; + rspi->chan_rx = dma_request_channel(mask, rspi_filter, + &rspi->dma_rx); + if (rspi->chan_rx) + dev_info(&pdev->dev, "Use DMA when rx.\n"); + } + if (rspi_pd->dma_tx_id) { + dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + rspi->dma_tx.slave_id = rspi_pd->dma_tx_id; + rspi->chan_tx = dma_request_channel(mask, rspi_filter, + &rspi->dma_tx); + if (rspi->chan_tx) + dev_info(&pdev->dev, "Use DMA when tx\n"); + } +} + +static void __devexit rspi_release_dma(struct rspi_data *rspi) +{ + if (rspi->chan_tx) + dma_release_channel(rspi->chan_tx); + if (rspi->chan_rx) + dma_release_channel(rspi->chan_rx); +} + static int __devexit rspi_remove(struct platform_device *pdev) { struct rspi_data *rspi = dev_get_drvdata(&pdev->dev); spi_unregister_master(rspi->master); + rspi_release_dma(rspi); free_irq(platform_get_irq(pdev, 0), rspi); clk_put(rspi->clk); iounmap(rspi->addr); @@ -483,6 +787,9 @@ static int __devinit rspi_probe(struct platform_device *pdev) goto error3; } + rspi->irq = irq; + rspi_request_dma(rspi, pdev); + ret = spi_register_master(master); if (ret < 0) { dev_err(&pdev->dev, "spi_register_master error.\n"); @@ -494,6 +801,7 @@ static int __devinit rspi_probe(struct platform_device *pdev) return 0; error4: + rspi_release_dma(rspi); free_irq(irq, rspi); error3: clk_put(rspi->clk); |