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author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-09 09:17:59 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-09 09:17:59 -0700 |
commit | c6b6cebbc597aaf7d941f781b5fc114c58cc3352 (patch) | |
tree | a99ad03f0f53552338db140f34c325e47c6b54e4 /drivers/spi/spi-at91-usart.c | |
parent | 98537ee92fb1b17a7f36dcbc8d2e4087af300da6 (diff) | |
parent | 26ac56506b0ea598bd0b52dcbd2d697282af98ed (diff) | |
download | linux-c6b6cebbc597aaf7d941f781b5fc114c58cc3352.tar.bz2 |
Merge tag 'spi-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi
Pull spi updates from Mark Brown:
"For the most part this is a quiet release for SPI, though there's
several of the more widely used drivers that have had some fairly
substantial development done on them, mainly improving performance and
adding support for some more obscure use cases.
Summary:
- Support for configuring a minimum time for chip select to be
deasserted between transfers from Martin Sperl.
- A rework of the ACPI device instantiation code from Ard Biesheuvel.
- Fairly substantial development on the AT91 USART, BCM2835 and
Tegra114 drivers.
- New driver for Socionext SynQuacer"
* tag 'spi-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (58 commits)
spi: pxa2xx: Add support for Intel Elkhart Lake
spi: atmel-quadspi: fix resume call
spi: atmel-quadspi: void return type for atmel_qspi_init()
spi: pxa2xx: Set minimum transfer speed
spi: stm32-qspi: remove signal sensitive on completion
dt-bindings: spi: stm32-qspi: add dma properties
spi: uniphier: fix zero-length transfer
spi: uniphier: fix timeout error
spi/acpi: avoid spurious matches during slave enumeration
spi: spi-stm32-qspi: Remove CR_FTHRES_MASK usage
spi: fix ctrl->num_chipselect constraint
spi: spi-synquacer: Fixed build on architectures missing readsl/writesl series
spi/acpi: fix incorrect ACPI parent check
spi: don't open code list_for_each_entry_safe_reverse()
spi: No need to assign dummy value in spi_unregister_controller()
spi: Add a prototype for exported spi_set_cs_timing()
spi/acpi: enumerate all SPI slaves in the namespace
spi: qup: fix PIO/DMA transfers.
spi: Use struct_size() helper
spi: mediatek: add SPI_LSB_FIRST support
...
Diffstat (limited to 'drivers/spi/spi-at91-usart.c')
-rw-r--r-- | drivers/spi/spi-at91-usart.c | 221 |
1 files changed, 219 insertions, 2 deletions
diff --git a/drivers/spi/spi-at91-usart.c b/drivers/spi/spi-at91-usart.c index f763e14bdf12..a40bb2ef89dc 100644 --- a/drivers/spi/spi-at91-usart.c +++ b/drivers/spi/spi-at91-usart.c @@ -8,9 +8,12 @@ #include <linux/clk.h> #include <linux/delay.h> +#include <linux/dmaengine.h> +#include <linux/dma-direction.h> #include <linux/interrupt.h> #include <linux/kernel.h> #include <linux/module.h> +#include <linux/of_platform.h> #include <linux/of_gpio.h> #include <linux/pinctrl/consumer.h> #include <linux/platform_device.h> @@ -59,6 +62,8 @@ #define US_INIT \ (US_MR_SPI_MASTER | US_MR_CHRL | US_MR_CLKO | US_MR_WRDBT) +#define US_DMA_MIN_BYTES 16 +#define US_DMA_TIMEOUT (msecs_to_jiffies(1000)) /* Register access macros */ #define at91_usart_spi_readl(port, reg) \ @@ -72,14 +77,19 @@ writeb_relaxed((value), (port)->regs + US_##reg) struct at91_usart_spi { + struct platform_device *mpdev; struct spi_transfer *current_transfer; void __iomem *regs; struct device *dev; struct clk *clk; + struct completion xfer_completion; + /*used in interrupt to protect data reading*/ spinlock_t lock; + phys_addr_t phybase; + int irq; unsigned int current_tx_remaining_bytes; unsigned int current_rx_remaining_bytes; @@ -88,8 +98,182 @@ struct at91_usart_spi { u32 status; bool xfer_failed; + bool use_dma; }; +static void dma_callback(void *data) +{ + struct spi_controller *ctlr = data; + struct at91_usart_spi *aus = spi_master_get_devdata(ctlr); + + at91_usart_spi_writel(aus, IER, US_IR_RXRDY); + aus->current_rx_remaining_bytes = 0; + complete(&aus->xfer_completion); +} + +static bool at91_usart_spi_can_dma(struct spi_controller *ctrl, + struct spi_device *spi, + struct spi_transfer *xfer) +{ + struct at91_usart_spi *aus = spi_master_get_devdata(ctrl); + + return aus->use_dma && xfer->len >= US_DMA_MIN_BYTES; +} + +static int at91_usart_spi_configure_dma(struct spi_controller *ctlr, + struct at91_usart_spi *aus) +{ + struct dma_slave_config slave_config; + struct device *dev = &aus->mpdev->dev; + phys_addr_t phybase = aus->phybase; + dma_cap_mask_t mask; + int err = 0; + + dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + + ctlr->dma_tx = dma_request_slave_channel_reason(dev, "tx"); + if (IS_ERR_OR_NULL(ctlr->dma_tx)) { + if (IS_ERR(ctlr->dma_tx)) { + err = PTR_ERR(ctlr->dma_tx); + goto at91_usart_spi_error_clear; + } + + dev_dbg(dev, + "DMA TX channel not available, SPI unable to use DMA\n"); + err = -EBUSY; + goto at91_usart_spi_error_clear; + } + + ctlr->dma_rx = dma_request_slave_channel_reason(dev, "rx"); + if (IS_ERR_OR_NULL(ctlr->dma_rx)) { + if (IS_ERR(ctlr->dma_rx)) { + err = PTR_ERR(ctlr->dma_rx); + goto at91_usart_spi_error; + } + + dev_dbg(dev, + "DMA RX channel not available, SPI unable to use DMA\n"); + err = -EBUSY; + goto at91_usart_spi_error; + } + + slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; + slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; + slave_config.dst_addr = (dma_addr_t)phybase + US_THR; + slave_config.src_addr = (dma_addr_t)phybase + US_RHR; + slave_config.src_maxburst = 1; + slave_config.dst_maxburst = 1; + slave_config.device_fc = false; + + slave_config.direction = DMA_DEV_TO_MEM; + if (dmaengine_slave_config(ctlr->dma_rx, &slave_config)) { + dev_err(&ctlr->dev, + "failed to configure rx dma channel\n"); + err = -EINVAL; + goto at91_usart_spi_error; + } + + slave_config.direction = DMA_MEM_TO_DEV; + if (dmaengine_slave_config(ctlr->dma_tx, &slave_config)) { + dev_err(&ctlr->dev, + "failed to configure tx dma channel\n"); + err = -EINVAL; + goto at91_usart_spi_error; + } + + aus->use_dma = true; + return 0; + +at91_usart_spi_error: + if (!IS_ERR_OR_NULL(ctlr->dma_tx)) + dma_release_channel(ctlr->dma_tx); + if (!IS_ERR_OR_NULL(ctlr->dma_rx)) + dma_release_channel(ctlr->dma_rx); + ctlr->dma_tx = NULL; + ctlr->dma_rx = NULL; + +at91_usart_spi_error_clear: + return err; +} + +static void at91_usart_spi_release_dma(struct spi_controller *ctlr) +{ + if (ctlr->dma_rx) + dma_release_channel(ctlr->dma_rx); + if (ctlr->dma_tx) + dma_release_channel(ctlr->dma_tx); +} + +static void at91_usart_spi_stop_dma(struct spi_controller *ctlr) +{ + if (ctlr->dma_rx) + dmaengine_terminate_all(ctlr->dma_rx); + if (ctlr->dma_tx) + dmaengine_terminate_all(ctlr->dma_tx); +} + +static int at91_usart_spi_dma_transfer(struct spi_controller *ctlr, + struct spi_transfer *xfer) +{ + struct at91_usart_spi *aus = spi_master_get_devdata(ctlr); + struct dma_chan *rxchan = ctlr->dma_rx; + struct dma_chan *txchan = ctlr->dma_tx; + struct dma_async_tx_descriptor *rxdesc; + struct dma_async_tx_descriptor *txdesc; + dma_cookie_t cookie; + + /* Disable RX interrupt */ + at91_usart_spi_writel(aus, IDR, US_IR_RXRDY); + + rxdesc = dmaengine_prep_slave_sg(rxchan, + xfer->rx_sg.sgl, + xfer->rx_sg.nents, + DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT | + DMA_CTRL_ACK); + if (!rxdesc) + goto at91_usart_spi_err_dma; + + txdesc = dmaengine_prep_slave_sg(txchan, + xfer->tx_sg.sgl, + xfer->tx_sg.nents, + DMA_MEM_TO_DEV, + DMA_PREP_INTERRUPT | + DMA_CTRL_ACK); + if (!txdesc) + goto at91_usart_spi_err_dma; + + rxdesc->callback = dma_callback; + rxdesc->callback_param = ctlr; + + cookie = rxdesc->tx_submit(rxdesc); + if (dma_submit_error(cookie)) + goto at91_usart_spi_err_dma; + + cookie = txdesc->tx_submit(txdesc); + if (dma_submit_error(cookie)) + goto at91_usart_spi_err_dma; + + rxchan->device->device_issue_pending(rxchan); + txchan->device->device_issue_pending(txchan); + + return 0; + +at91_usart_spi_err_dma: + /* Enable RX interrupt if something fails and fallback to PIO */ + at91_usart_spi_writel(aus, IER, US_IR_RXRDY); + at91_usart_spi_stop_dma(ctlr); + + return -ENOMEM; +} + +static unsigned long at91_usart_spi_dma_timeout(struct at91_usart_spi *aus) +{ + return wait_for_completion_timeout(&aus->xfer_completion, + US_DMA_TIMEOUT); +} + static inline u32 at91_usart_spi_tx_ready(struct at91_usart_spi *aus) { return aus->status & US_IR_TXRDY; @@ -216,6 +400,8 @@ static int at91_usart_spi_transfer_one(struct spi_controller *ctlr, struct spi_transfer *xfer) { struct at91_usart_spi *aus = spi_master_get_devdata(ctlr); + unsigned long dma_timeout = 0; + int ret = 0; at91_usart_spi_set_xfer_speed(aus, xfer); aus->xfer_failed = false; @@ -225,8 +411,25 @@ static int at91_usart_spi_transfer_one(struct spi_controller *ctlr, while ((aus->current_tx_remaining_bytes || aus->current_rx_remaining_bytes) && !aus->xfer_failed) { - at91_usart_spi_read_status(aus); - at91_usart_spi_tx(aus); + reinit_completion(&aus->xfer_completion); + if (at91_usart_spi_can_dma(ctlr, spi, xfer) && + !ret) { + ret = at91_usart_spi_dma_transfer(ctlr, xfer); + if (ret) + continue; + + dma_timeout = at91_usart_spi_dma_timeout(aus); + + if (WARN_ON(dma_timeout == 0)) { + dev_err(&spi->dev, "DMA transfer timeout\n"); + return -EIO; + } + aus->current_tx_remaining_bytes = 0; + } else { + at91_usart_spi_read_status(aus); + at91_usart_spi_tx(aus); + } + cpu_relax(); } @@ -345,6 +548,7 @@ static int at91_usart_spi_probe(struct platform_device *pdev) controller->transfer_one = at91_usart_spi_transfer_one; controller->prepare_message = at91_usart_spi_prepare_message; controller->unprepare_message = at91_usart_spi_unprepare_message; + controller->can_dma = at91_usart_spi_can_dma; controller->cleanup = at91_usart_spi_cleanup; controller->max_speed_hz = DIV_ROUND_UP(clk_get_rate(clk), US_MIN_CLK_DIV); @@ -376,7 +580,17 @@ static int at91_usart_spi_probe(struct platform_device *pdev) aus->spi_clk = clk_get_rate(clk); at91_usart_spi_init(aus); + aus->phybase = regs->start; + + aus->mpdev = to_platform_device(pdev->dev.parent); + + ret = at91_usart_spi_configure_dma(controller, aus); + if (ret) + goto at91_usart_fail_dma; + spin_lock_init(&aus->lock); + init_completion(&aus->xfer_completion); + ret = devm_spi_register_master(&pdev->dev, controller); if (ret) goto at91_usart_fail_register_master; @@ -389,6 +603,8 @@ static int at91_usart_spi_probe(struct platform_device *pdev) return 0; at91_usart_fail_register_master: + at91_usart_spi_release_dma(controller); +at91_usart_fail_dma: clk_disable_unprepare(clk); at91_usart_spi_probe_fail: spi_master_put(controller); @@ -453,6 +669,7 @@ static int at91_usart_spi_remove(struct platform_device *pdev) struct spi_controller *ctlr = platform_get_drvdata(pdev); struct at91_usart_spi *aus = spi_master_get_devdata(ctlr); + at91_usart_spi_release_dma(ctlr); clk_disable_unprepare(aus->clk); return 0; |