From 28d1dddc59f6b7fc085093e7c1e978b33f0caf4c Mon Sep 17 00:00:00 2001 From: Kunihiko Hayashi Date: Tue, 24 Dec 2019 09:58:27 +0900 Subject: spi: uniphier: Add DMA transfer mode support This adds DMA transfer mode support for UniPhier SPI controller. Since this controller requires simulteaneous transmission and reception, this indicates SPI_CONTROLLER_MUST_RX and SPI_CONTROLLER_MUST_TX. Because the supported dma controller has alignment restiction, there is also a restriction that 'maxburst' parameters in dma_slave_config corresponds to one word width. Signed-off-by: Kunihiko Hayashi Link: https://lore.kernel.org/r/1577149107-30670-6-git-send-email-hayashi.kunihiko@socionext.com Signed-off-by: Mark Brown --- drivers/spi/spi-uniphier.c | 200 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 198 insertions(+), 2 deletions(-) (limited to 'drivers/spi') diff --git a/drivers/spi/spi-uniphier.c b/drivers/spi/spi-uniphier.c index c4e3b96b1038..0fa50979644d 100644 --- a/drivers/spi/spi-uniphier.c +++ b/drivers/spi/spi-uniphier.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include #include @@ -23,6 +24,7 @@ struct uniphier_spi_priv { void __iomem *base; + dma_addr_t base_dma_addr; struct clk *clk; struct spi_master *master; struct completion xfer_done; @@ -32,6 +34,7 @@ struct uniphier_spi_priv { unsigned int rx_bytes; const u8 *tx_buf; u8 *rx_buf; + atomic_t dma_busy; bool is_save_param; u8 bits_per_word; @@ -61,11 +64,16 @@ struct uniphier_spi_priv { #define SSI_FPS_FSTRT BIT(14) #define SSI_SR 0x14 +#define SSI_SR_BUSY BIT(7) #define SSI_SR_RNE BIT(0) #define SSI_IE 0x18 +#define SSI_IE_TCIE BIT(4) #define SSI_IE_RCIE BIT(3) +#define SSI_IE_TXRE BIT(2) +#define SSI_IE_RXRE BIT(1) #define SSI_IE_RORIE BIT(0) +#define SSI_IE_ALL_MASK GENMASK(4, 0) #define SSI_IS 0x1c #define SSI_IS_RXRS BIT(9) @@ -87,6 +95,10 @@ struct uniphier_spi_priv { #define SSI_RXDR 0x24 #define SSI_FIFO_DEPTH 8U +#define SSI_FIFO_BURST_NUM 1 + +#define SSI_DMA_RX_BUSY BIT(1) +#define SSI_DMA_TX_BUSY BIT(0) static inline unsigned int bytes_per_word(unsigned int bits) { @@ -334,6 +346,128 @@ static void uniphier_spi_set_cs(struct spi_device *spi, bool enable) writel(val, priv->base + SSI_FPS); } +static bool uniphier_spi_can_dma(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *t) +{ + struct uniphier_spi_priv *priv = spi_master_get_devdata(master); + unsigned int bpw = bytes_per_word(priv->bits_per_word); + + if ((!master->dma_tx && !master->dma_rx) + || (!master->dma_tx && t->tx_buf) + || (!master->dma_rx && t->rx_buf)) + return false; + + return DIV_ROUND_UP(t->len, bpw) > SSI_FIFO_DEPTH; +} + +static void uniphier_spi_dma_rxcb(void *data) +{ + struct spi_master *master = data; + struct uniphier_spi_priv *priv = spi_master_get_devdata(master); + int state = atomic_fetch_andnot(SSI_DMA_RX_BUSY, &priv->dma_busy); + + uniphier_spi_irq_disable(priv, SSI_IE_RXRE); + + if (!(state & SSI_DMA_TX_BUSY)) + spi_finalize_current_transfer(master); +} + +static void uniphier_spi_dma_txcb(void *data) +{ + struct spi_master *master = data; + struct uniphier_spi_priv *priv = spi_master_get_devdata(master); + int state = atomic_fetch_andnot(SSI_DMA_TX_BUSY, &priv->dma_busy); + + uniphier_spi_irq_disable(priv, SSI_IE_TXRE); + + if (!(state & SSI_DMA_RX_BUSY)) + spi_finalize_current_transfer(master); +} + +static int uniphier_spi_transfer_one_dma(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *t) +{ + struct uniphier_spi_priv *priv = spi_master_get_devdata(master); + struct dma_async_tx_descriptor *rxdesc = NULL, *txdesc = NULL; + int buswidth; + + atomic_set(&priv->dma_busy, 0); + + uniphier_spi_set_fifo_threshold(priv, SSI_FIFO_BURST_NUM); + + if (priv->bits_per_word <= 8) + buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE; + else if (priv->bits_per_word <= 16) + buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES; + else + buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES; + + if (priv->rx_buf) { + struct dma_slave_config rxconf = { + .direction = DMA_DEV_TO_MEM, + .src_addr = priv->base_dma_addr + SSI_RXDR, + .src_addr_width = buswidth, + .src_maxburst = SSI_FIFO_BURST_NUM, + }; + + dmaengine_slave_config(master->dma_rx, &rxconf); + + rxdesc = dmaengine_prep_slave_sg( + master->dma_rx, + t->rx_sg.sgl, t->rx_sg.nents, + DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!rxdesc) + goto out_err_prep; + + rxdesc->callback = uniphier_spi_dma_rxcb; + rxdesc->callback_param = master; + + uniphier_spi_irq_enable(priv, SSI_IE_RXRE); + atomic_or(SSI_DMA_RX_BUSY, &priv->dma_busy); + + dmaengine_submit(rxdesc); + dma_async_issue_pending(master->dma_rx); + } + + if (priv->tx_buf) { + struct dma_slave_config txconf = { + .direction = DMA_MEM_TO_DEV, + .dst_addr = priv->base_dma_addr + SSI_TXDR, + .dst_addr_width = buswidth, + .dst_maxburst = SSI_FIFO_BURST_NUM, + }; + + dmaengine_slave_config(master->dma_tx, &txconf); + + txdesc = dmaengine_prep_slave_sg( + master->dma_tx, + t->tx_sg.sgl, t->tx_sg.nents, + DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!txdesc) + goto out_err_prep; + + txdesc->callback = uniphier_spi_dma_txcb; + txdesc->callback_param = master; + + uniphier_spi_irq_enable(priv, SSI_IE_TXRE); + atomic_or(SSI_DMA_TX_BUSY, &priv->dma_busy); + + dmaengine_submit(txdesc); + dma_async_issue_pending(master->dma_tx); + } + + /* signal that we need to wait for completion */ + return (priv->tx_buf || priv->rx_buf); + +out_err_prep: + if (rxdesc) + dmaengine_terminate_sync(master->dma_rx); + + return -EINVAL; +} + static int uniphier_spi_transfer_one_irq(struct spi_master *master, struct spi_device *spi, struct spi_transfer *t) @@ -395,6 +529,7 @@ static int uniphier_spi_transfer_one(struct spi_master *master, { struct uniphier_spi_priv *priv = spi_master_get_devdata(master); unsigned long threshold; + bool use_dma; /* Terminate and return success for 0 byte length transfer */ if (!t->len) @@ -402,6 +537,10 @@ static int uniphier_spi_transfer_one(struct spi_master *master, uniphier_spi_setup_transfer(spi, t); + use_dma = master->can_dma ? master->can_dma(master, spi, t) : false; + if (use_dma) + return uniphier_spi_transfer_one_dma(master, spi, t); + /* * If the transfer operation will take longer than * SSI_POLL_TIMEOUT_US, it should use irq. @@ -445,7 +584,17 @@ static void uniphier_spi_handle_err(struct spi_master *master, val = SSI_FC_TXFFL | SSI_FC_RXFFL; writel(val, priv->base + SSI_FC); - uniphier_spi_irq_disable(priv, SSI_IE_RCIE | SSI_IE_RORIE); + uniphier_spi_irq_disable(priv, SSI_IE_ALL_MASK); + + if (atomic_read(&priv->dma_busy) & SSI_DMA_TX_BUSY) { + dmaengine_terminate_async(master->dma_tx); + atomic_andnot(SSI_DMA_TX_BUSY, &priv->dma_busy); + } + + if (atomic_read(&priv->dma_busy) & SSI_DMA_RX_BUSY) { + dmaengine_terminate_async(master->dma_rx); + atomic_andnot(SSI_DMA_RX_BUSY, &priv->dma_busy); + } } static irqreturn_t uniphier_spi_handler(int irq, void *dev_id) @@ -493,6 +642,9 @@ static int uniphier_spi_probe(struct platform_device *pdev) { struct uniphier_spi_priv *priv; struct spi_master *master; + struct resource *res; + struct dma_slave_caps caps; + u32 dma_tx_burst = 0, dma_rx_burst = 0; unsigned long clk_rate; int irq; int ret; @@ -507,11 +659,13 @@ static int uniphier_spi_probe(struct platform_device *pdev) priv->master = master; priv->is_save_param = false; - priv->base = devm_platform_ioremap_resource(pdev, 0); + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + priv->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(priv->base)) { ret = PTR_ERR(priv->base); goto out_master_put; } + priv->base_dma_addr = res->start; priv->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(priv->clk)) { @@ -555,7 +709,44 @@ static int uniphier_spi_probe(struct platform_device *pdev) master->unprepare_transfer_hardware = uniphier_spi_unprepare_transfer_hardware; master->handle_err = uniphier_spi_handle_err; + master->can_dma = uniphier_spi_can_dma; + master->num_chipselect = 1; + master->flags = SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX; + + master->dma_tx = dma_request_chan(&pdev->dev, "tx"); + if (IS_ERR_OR_NULL(master->dma_tx)) { + if (PTR_ERR(master->dma_tx) == -EPROBE_DEFER) + goto out_disable_clk; + master->dma_tx = NULL; + dma_tx_burst = INT_MAX; + } else { + ret = dma_get_slave_caps(master->dma_tx, &caps); + if (ret) { + dev_err(&pdev->dev, "failed to get TX DMA capacities: %d\n", + ret); + goto out_disable_clk; + } + dma_tx_burst = caps.max_burst; + } + + master->dma_rx = dma_request_chan(&pdev->dev, "rx"); + if (IS_ERR_OR_NULL(master->dma_rx)) { + if (PTR_ERR(master->dma_rx) == -EPROBE_DEFER) + goto out_disable_clk; + master->dma_rx = NULL; + dma_rx_burst = INT_MAX; + } else { + ret = dma_get_slave_caps(master->dma_rx, &caps); + if (ret) { + dev_err(&pdev->dev, "failed to get RX DMA capacities: %d\n", + ret); + goto out_disable_clk; + } + dma_rx_burst = caps.max_burst; + } + + master->max_dma_len = min(dma_tx_burst, dma_rx_burst); ret = devm_spi_register_master(&pdev->dev, master); if (ret) @@ -575,6 +766,11 @@ static int uniphier_spi_remove(struct platform_device *pdev) { struct uniphier_spi_priv *priv = platform_get_drvdata(pdev); + if (priv->master->dma_tx) + dma_release_channel(priv->master->dma_tx); + if (priv->master->dma_rx) + dma_release_channel(priv->master->dma_rx); + clk_disable_unprepare(priv->clk); return 0; -- cgit