diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/Kconfig | 4 | ||||
| -rw-r--r-- | drivers/spi/spi-ath79.c | 34 | ||||
| -rw-r--r-- | drivers/spi/spi-atmel.c | 292 | ||||
| -rw-r--r-- | drivers/spi/spi-bcm2835.c | 393 | ||||
| -rw-r--r-- | drivers/spi/spi-bitbang.c | 17 | ||||
| -rw-r--r-- | drivers/spi/spi-davinci.c | 2 | ||||
| -rw-r--r-- | drivers/spi/spi-fsl-cpm.c | 40 | ||||
| -rw-r--r-- | drivers/spi/spi-fsl-dspi.c | 307 | ||||
| -rw-r--r-- | drivers/spi/spi-fsl-espi.c | 51 | ||||
| -rw-r--r-- | drivers/spi/spi-imx.c | 2 | ||||
| -rw-r--r-- | drivers/spi/spi-omap2-mcspi.c | 270 | ||||
| -rw-r--r-- | drivers/spi/spi-orion.c | 70 | ||||
| -rw-r--r-- | drivers/spi/spi.c | 36 |
13 files changed, 1168 insertions, 350 deletions
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index 1c18c46d6598..7183be8a3c92 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -77,7 +77,9 @@ config SPI_ATMEL config SPI_BCM2835 tristate "BCM2835 SPI controller" + depends on GPIOLIB depends on ARCH_BCM2835 || COMPILE_TEST + depends on GPIOLIB help This selects a driver for the Broadcom BCM2835 SPI master. @@ -302,7 +304,7 @@ config SPI_FSL_SPI config SPI_FSL_DSPI tristate "Freescale DSPI controller" select REGMAP_MMIO - depends on SOC_VF610 || COMPILE_TEST + depends on SOC_VF610 || SOC_LS1021A || COMPILE_TEST help This enables support for the Freescale DSPI controller in master mode. VF610 platform uses the controller. diff --git a/drivers/spi/spi-ath79.c b/drivers/spi/spi-ath79.c index b02eb4ac0218..bf1f9b32c597 100644 --- a/drivers/spi/spi-ath79.c +++ b/drivers/spi/spi-ath79.c @@ -79,10 +79,8 @@ static void ath79_spi_chipselect(struct spi_device *spi, int is_active) } if (spi->chip_select) { - struct ath79_spi_controller_data *cdata = spi->controller_data; - /* SPI is normally active-low */ - gpio_set_value(cdata->gpio, cs_high); + gpio_set_value(spi->cs_gpio, cs_high); } else { if (cs_high) sp->ioc_base |= AR71XX_SPI_IOC_CS0; @@ -117,11 +115,10 @@ static void ath79_spi_disable(struct ath79_spi *sp) static int ath79_spi_setup_cs(struct spi_device *spi) { - struct ath79_spi_controller_data *cdata; + struct ath79_spi *sp = ath79_spidev_to_sp(spi); int status; - cdata = spi->controller_data; - if (spi->chip_select && !cdata) + if (spi->chip_select && !gpio_is_valid(spi->cs_gpio)) return -EINVAL; status = 0; @@ -134,8 +131,15 @@ static int ath79_spi_setup_cs(struct spi_device *spi) else flags |= GPIOF_INIT_HIGH; - status = gpio_request_one(cdata->gpio, flags, + status = gpio_request_one(spi->cs_gpio, flags, dev_name(&spi->dev)); + } else { + if (spi->mode & SPI_CS_HIGH) + sp->ioc_base &= ~AR71XX_SPI_IOC_CS0; + else + sp->ioc_base |= AR71XX_SPI_IOC_CS0; + + ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, sp->ioc_base); } return status; @@ -144,8 +148,7 @@ static int ath79_spi_setup_cs(struct spi_device *spi) static void ath79_spi_cleanup_cs(struct spi_device *spi) { if (spi->chip_select) { - struct ath79_spi_controller_data *cdata = spi->controller_data; - gpio_free(cdata->gpio); + gpio_free(spi->cs_gpio); } } @@ -217,6 +220,7 @@ static int ath79_spi_probe(struct platform_device *pdev) } sp = spi_master_get_devdata(master); + master->dev.of_node = pdev->dev.of_node; platform_set_drvdata(pdev, sp); pdata = dev_get_platdata(&pdev->dev); @@ -253,7 +257,7 @@ static int ath79_spi_probe(struct platform_device *pdev) goto err_put_master; } - ret = clk_enable(sp->clk); + ret = clk_prepare_enable(sp->clk); if (ret) goto err_put_master; @@ -277,7 +281,7 @@ static int ath79_spi_probe(struct platform_device *pdev) err_disable: ath79_spi_disable(sp); err_clk_disable: - clk_disable(sp->clk); + clk_disable_unprepare(sp->clk); err_put_master: spi_master_put(sp->bitbang.master); @@ -290,7 +294,7 @@ static int ath79_spi_remove(struct platform_device *pdev) spi_bitbang_stop(&sp->bitbang); ath79_spi_disable(sp); - clk_disable(sp->clk); + clk_disable_unprepare(sp->clk); spi_master_put(sp->bitbang.master); return 0; @@ -301,12 +305,18 @@ static void ath79_spi_shutdown(struct platform_device *pdev) ath79_spi_remove(pdev); } +static const struct of_device_id ath79_spi_of_match[] = { + { .compatible = "qca,ar7100-spi", }, + { }, +}; + static struct platform_driver ath79_spi_driver = { .probe = ath79_spi_probe, .remove = ath79_spi_remove, .shutdown = ath79_spi_shutdown, .driver = { .name = DRV_NAME, + .of_match_table = ath79_spi_of_match, }, }; module_platform_driver(ath79_spi_driver); diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c index a2f40b1b2225..c9eca347787d 100644 --- a/drivers/spi/spi-atmel.c +++ b/drivers/spi/spi-atmel.c @@ -41,6 +41,8 @@ #define SPI_CSR1 0x0034 #define SPI_CSR2 0x0038 #define SPI_CSR3 0x003c +#define SPI_FMR 0x0040 +#define SPI_FLR 0x0044 #define SPI_VERSION 0x00fc #define SPI_RPR 0x0100 #define SPI_RCR 0x0104 @@ -62,6 +64,14 @@ #define SPI_SWRST_SIZE 1 #define SPI_LASTXFER_OFFSET 24 #define SPI_LASTXFER_SIZE 1 +#define SPI_TXFCLR_OFFSET 16 +#define SPI_TXFCLR_SIZE 1 +#define SPI_RXFCLR_OFFSET 17 +#define SPI_RXFCLR_SIZE 1 +#define SPI_FIFOEN_OFFSET 30 +#define SPI_FIFOEN_SIZE 1 +#define SPI_FIFODIS_OFFSET 31 +#define SPI_FIFODIS_SIZE 1 /* Bitfields in MR */ #define SPI_MSTR_OFFSET 0 @@ -114,6 +124,22 @@ #define SPI_TXEMPTY_SIZE 1 #define SPI_SPIENS_OFFSET 16 #define SPI_SPIENS_SIZE 1 +#define SPI_TXFEF_OFFSET 24 +#define SPI_TXFEF_SIZE 1 +#define SPI_TXFFF_OFFSET 25 +#define SPI_TXFFF_SIZE 1 +#define SPI_TXFTHF_OFFSET 26 +#define SPI_TXFTHF_SIZE 1 +#define SPI_RXFEF_OFFSET 27 +#define SPI_RXFEF_SIZE 1 +#define SPI_RXFFF_OFFSET 28 +#define SPI_RXFFF_SIZE 1 +#define SPI_RXFTHF_OFFSET 29 +#define SPI_RXFTHF_SIZE 1 +#define SPI_TXFPTEF_OFFSET 30 +#define SPI_TXFPTEF_SIZE 1 +#define SPI_RXFPTEF_OFFSET 31 +#define SPI_RXFPTEF_SIZE 1 /* Bitfields in CSR0 */ #define SPI_CPOL_OFFSET 0 @@ -157,6 +183,22 @@ #define SPI_TXTDIS_OFFSET 9 #define SPI_TXTDIS_SIZE 1 +/* Bitfields in FMR */ +#define SPI_TXRDYM_OFFSET 0 +#define SPI_TXRDYM_SIZE 2 +#define SPI_RXRDYM_OFFSET 4 +#define SPI_RXRDYM_SIZE 2 +#define SPI_TXFTHRES_OFFSET 16 +#define SPI_TXFTHRES_SIZE 6 +#define SPI_RXFTHRES_OFFSET 24 +#define SPI_RXFTHRES_SIZE 6 + +/* Bitfields in FLR */ +#define SPI_TXFL_OFFSET 0 +#define SPI_TXFL_SIZE 6 +#define SPI_RXFL_OFFSET 16 +#define SPI_RXFL_SIZE 6 + /* Constants for BITS */ #define SPI_BITS_8_BPT 0 #define SPI_BITS_9_BPT 1 @@ -167,6 +209,9 @@ #define SPI_BITS_14_BPT 6 #define SPI_BITS_15_BPT 7 #define SPI_BITS_16_BPT 8 +#define SPI_ONE_DATA 0 +#define SPI_TWO_DATA 1 +#define SPI_FOUR_DATA 2 /* Bit manipulation macros */ #define SPI_BIT(name) \ @@ -185,11 +230,31 @@ __raw_readl((port)->regs + SPI_##reg) #define spi_writel(port, reg, value) \ __raw_writel((value), (port)->regs + SPI_##reg) + +#define spi_readw(port, reg) \ + __raw_readw((port)->regs + SPI_##reg) +#define spi_writew(port, reg, value) \ + __raw_writew((value), (port)->regs + SPI_##reg) + +#define spi_readb(port, reg) \ + __raw_readb((port)->regs + SPI_##reg) +#define spi_writeb(port, reg, value) \ + __raw_writeb((value), (port)->regs + SPI_##reg) #else #define spi_readl(port, reg) \ readl_relaxed((port)->regs + SPI_##reg) #define spi_writel(port, reg, value) \ writel_relaxed((value), (port)->regs + SPI_##reg) + +#define spi_readw(port, reg) \ + readw_relaxed((port)->regs + SPI_##reg) +#define spi_writew(port, reg, value) \ + writew_relaxed((value), (port)->regs + SPI_##reg) + +#define spi_readb(port, reg) \ + readb_relaxed((port)->regs + SPI_##reg) +#define spi_writeb(port, reg, value) \ + writeb_relaxed((value), (port)->regs + SPI_##reg) #endif /* use PIO for small transfers, avoiding DMA setup/teardown overhead and * cache operations; better heuristics consider wordsize and bitrate. @@ -246,11 +311,14 @@ struct atmel_spi { bool use_dma; bool use_pdc; + bool use_cs_gpios; /* dmaengine data */ struct atmel_spi_dma dma; bool keep_cs; bool cs_active; + + u32 fifo_size; }; /* Controller-specific per-slave state */ @@ -321,7 +389,8 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi) } mr = spi_readl(as, MR); - gpio_set_value(asd->npcs_pin, active); + if (as->use_cs_gpios) + gpio_set_value(asd->npcs_pin, active); } else { u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0; int i; @@ -337,7 +406,7 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi) mr = spi_readl(as, MR); mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr); - if (spi->chip_select != 0) + if (as->use_cs_gpios && spi->chip_select != 0) gpio_set_value(asd->npcs_pin, active); spi_writel(as, MR, mr); } @@ -366,7 +435,9 @@ static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi) asd->npcs_pin, active ? " (low)" : "", mr); - if (atmel_spi_is_v2(as) || spi->chip_select != 0) + if (!as->use_cs_gpios) + spi_writel(as, CR, SPI_BIT(LASTXFER)); + else if (atmel_spi_is_v2(as) || spi->chip_select != 0) gpio_set_value(asd->npcs_pin, !active); } @@ -406,6 +477,20 @@ static int atmel_spi_dma_slave_config(struct atmel_spi *as, slave_config->dst_maxburst = 1; slave_config->device_fc = false; + /* + * This driver uses fixed peripheral select mode (PS bit set to '0' in + * the Mode Register). + * So according to the datasheet, when FIFOs are available (and + * enabled), the Transmit FIFO operates in Multiple Data Mode. + * In this mode, up to 2 data, not 4, can be written into the Transmit + * Data Register in a single access. + * However, the first data has to be written into the lowest 16 bits and + * the second data into the highest 16 bits of the Transmit + * Data Register. For 8bit data (the most frequent case), it would + * require to rework tx_buf so each data would actualy fit 16 bits. + * So we'd rather write only one data at the time. Hence the transmit + * path works the same whether FIFOs are available (and enabled) or not. + */ slave_config->direction = DMA_MEM_TO_DEV; if (dmaengine_slave_config(as->dma.chan_tx, slave_config)) { dev_err(&as->pdev->dev, @@ -413,6 +498,14 @@ static int atmel_spi_dma_slave_config(struct atmel_spi *as, err = -EINVAL; } + /* + * This driver configures the spi controller for master mode (MSTR bit + * set to '1' in the Mode Register). + * So according to the datasheet, when FIFOs are available (and + * enabled), the Receive FIFO operates in Single Data Mode. + * So the receive path works the same whether FIFOs are available (and + * enabled) or not. + */ slave_config->direction = DMA_DEV_TO_MEM; if (dmaengine_slave_config(as->dma.chan_rx, slave_config)) { dev_err(&as->pdev->dev, @@ -502,10 +595,10 @@ static void dma_callback(void *data) } /* - * Next transfer using PIO. + * Next transfer using PIO without FIFO. */ -static void atmel_spi_next_xfer_pio(struct spi_master *master, - struct spi_transfer *xfer) +static void atmel_spi_next_xfer_single(struct spi_master *master, + struct spi_transfer *xfer) { struct atmel_spi *as = spi_master_get_devdata(master); unsigned long xfer_pos = xfer->len - as->current_remaining_bytes; @@ -538,6 +631,99 @@ static void atmel_spi_next_xfer_pio(struct spi_master *master, } /* + * Next transfer using PIO with FIFO. + */ +static void atmel_spi_next_xfer_fifo(struct spi_master *master, + struct spi_transfer *xfer) +{ + struct atmel_spi *as = spi_master_get_devdata(master); + u32 current_remaining_data, num_data; + u32 offset = xfer->len - as->current_remaining_bytes; + const u16 *words = (const u16 *)((u8 *)xfer->tx_buf + offset); + const u8 *bytes = (const u8 *)((u8 *)xfer->tx_buf + offset); + u16 td0, td1; + u32 fifomr; + + dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_fifo\n"); + + /* Compute the number of data to transfer in the current iteration */ + current_remaining_data = ((xfer->bits_per_word > 8) ? + ((u32)as->current_remaining_bytes >> 1) : + (u32)as->current_remaining_bytes); + num_data = min(current_remaining_data, as->fifo_size); + + /* Flush RX and TX FIFOs */ + spi_writel(as, CR, SPI_BIT(RXFCLR) | SPI_BIT(TXFCLR)); + while (spi_readl(as, FLR)) + cpu_relax(); + + /* Set RX FIFO Threshold to the number of data to transfer */ + fifomr = spi_readl(as, FMR); + spi_writel(as, FMR, SPI_BFINS(RXFTHRES, num_data, fifomr)); + + /* Clear FIFO flags in the Status Register, especially RXFTHF */ + (void)spi_readl(as, SR); + + /* Fill TX FIFO */ + while (num_data >= 2) { + if (xfer->tx_buf) { + if (xfer->bits_per_word > 8) { + td0 = *words++; + td1 = *words++; + } else { + td0 = *bytes++; + td1 = *bytes++; + } + } else { + td0 = 0; + td1 = 0; + } + + spi_writel(as, TDR, (td1 << 16) | td0); + num_data -= 2; + } + + if (num_data) { + if (xfer->tx_buf) { + if (xfer->bits_per_word > 8) + td0 = *words++; + else + td0 = *bytes++; + } else { + td0 = 0; + } + + spi_writew(as, TDR, td0); + num_data--; + } + + dev_dbg(master->dev.parent, + " start fifo xfer %p: len %u tx %p rx %p bitpw %d\n", + xfer, xfer->len, xfer->tx_buf, xfer->rx_buf, + xfer->bits_per_word); + + /* + * Enable RX FIFO Threshold Flag interrupt to be notified about + * transfer completion. + */ + spi_writel(as, IER, SPI_BIT(RXFTHF) | SPI_BIT(OVRES)); +} + +/* + * Next transfer using PIO. + */ +static void atmel_spi_next_xfer_pio(struct spi_master *master, + struct spi_transfer *xfer) +{ + struct atmel_spi *as = spi_master_get_devdata(master); + + if (as->fifo_size) + atmel_spi_next_xfer_fifo(master, xfer); + else + atmel_spi_next_xfer_single(master, xfer); +} + +/* * Submit next transfer for DMA. */ static int atmel_spi_next_xfer_dma_submit(struct spi_master *master, @@ -839,13 +1025,8 @@ static void atmel_spi_disable_pdc_transfer(struct atmel_spi *as) spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS)); } -/* Called from IRQ - * - * Must update "current_remaining_bytes" to keep track of data - * to transfer. - */ static void -atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer) +atmel_spi_pump_single_data(struct atmel_spi *as, struct spi_transfer *xfer) { u8 *rxp; u16 *rxp16; @@ -872,6 +1053,57 @@ atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer) } } +static void +atmel_spi_pump_fifo_data(struct atmel_spi *as, struct spi_transfer *xfer) +{ + u32 fifolr = spi_readl(as, FLR); + u32 num_bytes, num_data = SPI_BFEXT(RXFL, fifolr); + u32 offset = xfer->len - as->current_remaining_bytes; + u16 *words = (u16 *)((u8 *)xfer->rx_buf + offset); + u8 *bytes = (u8 *)((u8 *)xfer->rx_buf + offset); + u16 rd; /* RD field is the lowest 16 bits of RDR */ + + /* Update the number of remaining bytes to transfer */ + num_bytes = ((xfer->bits_per_word > 8) ? + (num_data << 1) : + num_data); + + if (as->current_remaining_bytes > num_bytes) + as->current_remaining_bytes -= num_bytes; + else + as->current_remaining_bytes = 0; + + /* Handle odd number of bytes when data are more than 8bit width */ + if (xfer->bits_per_word > 8) + as->current_remaining_bytes &= ~0x1; + + /* Read data */ + while (num_data) { + rd = spi_readl(as, RDR); + if (xfer->rx_buf) { + if (xfer->bits_per_word > 8) + *words++ = rd; + else + *bytes++ = rd; + } + num_data--; + } +} + +/* Called from IRQ + * + * Must update "current_remaining_bytes" to keep track of data + * to transfer. + */ +static void +atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer) +{ + if (as->fifo_size) + atmel_spi_pump_fifo_data(as, xfer); + else + atmel_spi_pump_single_data(as, xfer); +} + /* Interrupt * * No need for locking in this Interrupt handler: done_status is the @@ -912,7 +1144,7 @@ atmel_spi_pio_interrupt(int irq, void *dev_id) complete(&as->xfer_completion); - } else if (pending & SPI_BIT(RDRF)) { + } else if (pending & (SPI_BIT(RDRF) | SPI_BIT(RXFTHF))) { atmel_spi_lock(as); if (as->current_remaining_bytes) { @@ -996,6 +1228,8 @@ static int atmel_spi_setup(struct spi_device *spi) csr |= SPI_BIT(CPOL); if (!(spi->mode & SPI_CPHA)) csr |= SPI_BIT(NCPHA); + if (!as->use_cs_gpios) + csr |= SPI_BIT(CSAAT); /* DLYBS is mostly irrelevant since we manage chipselect using GPIOs. * @@ -1009,7 +1243,9 @@ static int atmel_spi_setup(struct spi_device *spi) /* chipselect must have been muxed as GPIO (e.g. in board setup) */ npcs_pin = (unsigned long)spi->controller_data; - if (gpio_is_valid(spi->cs_gpio)) + if (!as->use_cs_gpios) + npcs_pin = spi->chip_select; + else if (gpio_is_valid(spi->cs_gpio)) npcs_pin = spi->cs_gpio; asd = spi->controller_state; @@ -1018,15 +1254,19 @@ static int atmel_spi_setup(struct spi_device *spi) if (!asd) return -ENOMEM; - ret = gpio_request(npcs_pin, dev_name(&spi->dev)); - if (ret) { - kfree(asd); - return ret; + if (as->use_cs_gpios) { + ret = gpio_request(npcs_pin, dev_name(&spi->dev)); + if (ret) { + kfree(asd); + return ret; + } + + gpio_direction_output(npcs_pin, + !(spi->mode & SPI_CS_HIGH)); } asd->npcs_pin = npcs_pin; spi->controller_state = asd; - gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH)); } asd->csr = csr; @@ -1338,6 +1578,13 @@ static int atmel_spi_probe(struct platform_device *pdev) atmel_get_caps(as); + as->use_cs_gpios = true; + if (atmel_spi_is_v2(as) && + !of_get_property(pdev->dev.of_node, "cs-gpios", NULL)) { + as->use_cs_gpios = false; + master->num_chipselect = 4; + } + as->use_dma = false; as->use_pdc = false; if (as->caps.has_dma_support) { @@ -1380,6 +1627,13 @@ static int atmel_spi_probe(struct platform_device *pdev) spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS)); spi_writel(as, CR, SPI_BIT(SPIEN)); + as->fifo_size = 0; + if (!of_property_read_u32(pdev->dev.of_node, "atmel,fifo-size", + &as->fifo_size)) { + dev_info(&pdev->dev, "Using FIFO (%u data)\n", as->fifo_size); + spi_writel(as, CR, SPI_BIT(FIFOEN)); + } + /* go! */ dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n", (unsigned long)regs->start, irq); diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index f63864a893c5..59705ab23577 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -20,18 +20,22 @@ * GNU General Public License for more details. */ +#include <asm/page.h> #include <linux/clk.h> #include <linux/completion.h> #include <linux/delay.h> +#include <linux/dma-mapping.h> +#include <linux/dmaengine.h> #include <linux/err.h> #include <linux/interrupt.h> #include <linux/io.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/of.h> -#include <linux/of_irq.h> -#include <linux/of_gpio.h> +#include <linux/of_address.h> #include <linux/of_device.h> +#include <linux/of_gpio.h> +#include <linux/of_irq.h> #include <linux/spi/spi.h> /* SPI register offsets */ @@ -69,7 +73,8 @@ #define BCM2835_SPI_CS_CS_01 0x00000001 #define BCM2835_SPI_POLLING_LIMIT_US 30 -#define BCM2835_SPI_TIMEOUT_MS 30000 +#define BCM2835_SPI_POLLING_JIFFIES 2 +#define BCM2835_SPI_DMA_MIN_LENGTH 96 #define BCM2835_SPI_MODE_BITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH \ | SPI_NO_CS | SPI_3WIRE) @@ -83,6 +88,7 @@ struct bcm2835_spi { u8 *rx_buf; int tx_len; int rx_len; + bool dma_pending; }; static inline u32 bcm2835_rd(struct bcm2835_spi *bs, unsigned reg) @@ -128,12 +134,15 @@ static void bcm2835_spi_reset_hw(struct spi_master *master) /* Disable SPI interrupts and transfer */ cs &= ~(BCM2835_SPI_CS_INTR | BCM2835_SPI_CS_INTD | + BCM2835_SPI_CS_DMAEN | BCM2835_SPI_CS_TA); /* and reset RX/TX FIFOS */ cs |= BCM2835_SPI_CS_CLEAR_RX | BCM2835_SPI_CS_CLEAR_TX; /* and reset the SPI_HW */ bcm2835_wr(bs, BCM2835_SPI_CS, cs); + /* as well as DLEN */ + bcm2835_wr(bs, BCM2835_SPI_DLEN, 0); } static irqreturn_t bcm2835_spi_interrupt(int irq, void *dev_id) @@ -157,43 +166,6 @@ static irqreturn_t bcm2835_spi_interrupt(int irq, void *dev_id) return IRQ_HANDLED; } -static int bcm2835_spi_transfer_one_poll(struct spi_master *master, - struct spi_device *spi, - struct spi_transfer *tfr, - u32 cs, - unsigned long xfer_time_us) -{ - struct bcm2835_spi *bs = spi_master_get_devdata(master); - unsigned long timeout = jiffies + - max(4 * xfer_time_us * HZ / 1000000, 2uL); - - /* enable HW block without interrupts */ - bcm2835_wr(bs, BCM2835_SPI_CS, cs | BCM2835_SPI_CS_TA); - - /* set timeout to 4x the expected time, or 2 jiffies */ - /* loop until finished the transfer */ - while (bs->rx_len) { - /* read from fifo as much as possible */ - bcm2835_rd_fifo(bs); - /* fill in tx fifo as much as possible */ - bcm2835_wr_fifo(bs); - /* if we still expect some data after the read, - * check for a possible timeout - */ - if (bs->rx_len && time_after(jiffies, timeout)) { - /* Transfer complete - reset SPI HW */ - bcm2835_spi_reset_hw(master); - /* and return timeout */ - return -ETIMEDOUT; - } - } - - /* Transfer complete - reset SPI HW */ - bcm2835_spi_reset_hw(master); - /* and return without waiting for completion */ - return 0; -} - static int bcm2835_spi_transfer_one_irq(struct spi_master *master, struct spi_device *spi, struct spi_transfer *tfr, @@ -230,6 +202,329 @@ static int bcm2835_spi_transfer_one_irq(struct spi_master *master, return 1; } +/* + * DMA support + * + * this implementation has currently a few issues in so far as it does + * not work arrount limitations of the HW. + * + * the main one being that DMA transfers are limited to 16 bit + * (so 0 to 65535 bytes) by the SPI HW due to BCM2835_SPI_DLEN + * + * also we currently assume that the scatter-gather fragments are + * all multiple of 4 (except the last) - otherwise we would need + * to reset the FIFO before subsequent transfers... + * this also means that tx/rx transfers sg's need to be of equal size! + * + * there may be a few more border-cases we may need to address as well + * but unfortunately this would mean splitting up the scatter-gather + * list making it slightly unpractical... + */ +static void bcm2835_spi_dma_done(void *data) +{ + struct spi_master *master = data; + struct bcm2835_spi *bs = spi_master_get_devdata(master); + + /* reset fifo and HW */ + bcm2835_spi_reset_hw(master); + + /* and terminate tx-dma as we do not have an irq for it + * because when the rx dma will terminate and this callback + * is called the tx-dma must have finished - can't get to this + * situation otherwise... + */ + dmaengine_terminate_all(master->dma_tx); + + /* mark as no longer pending */ + bs->dma_pending = 0; + + /* and mark as completed */; + complete(&master->xfer_completion); +} + +static int bcm2835_spi_prepare_sg(struct spi_master *master, + struct spi_transfer *tfr, + bool is_tx) +{ + struct dma_chan *chan; + struct scatterlist *sgl; + unsigned int nents; + enum dma_transfer_direction dir; + unsigned long flags; + + struct dma_async_tx_descriptor *desc; + dma_cookie_t cookie; + + if (is_tx) { + dir = DMA_MEM_TO_DEV; + chan = master->dma_tx; + nents = tfr->tx_sg.nents; + sgl = tfr->tx_sg.sgl; + flags = 0 /* no tx interrupt */; + + } else { + dir = DMA_DEV_TO_MEM; + chan = master->dma_rx; + nents = tfr->rx_sg.nents; + sgl = tfr->rx_sg.sgl; + flags = DMA_PREP_INTERRUPT; + } + /* prepare the channel */ + desc = dmaengine_prep_slave_sg(chan, sgl, nents, dir, flags); + if (!desc) + return -EINVAL; + + /* set callback for rx */ + if (!is_tx) { + desc->callback = bcm2835_spi_dma_done; + desc->callback_param = master; + } + + /* submit it to DMA-engine */ + cookie = dmaengine_submit(desc); + + return dma_submit_error(cookie); +} + +static inline int bcm2835_check_sg_length(struct sg_table *sgt) +{ + int i; + struct scatterlist *sgl; + + /* check that the sg entries are word-sized (except for last) */ + for_each_sg(sgt->sgl, sgl, (int)sgt->nents - 1, i) { + if (sg_dma_len(sgl) % 4) + return -EFAULT; + } + + return 0; +} + +static int bcm2835_spi_transfer_one_dma(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *tfr, + u32 cs) +{ + struct bcm2835_spi *bs = spi_master_get_devdata(master); + int ret; + + /* check that the scatter gather segments are all a multiple of 4 */ + if (bcm2835_check_sg_length(&tfr->tx_sg) || + bcm2835_check_sg_length(&tfr->rx_sg)) { + dev_warn_once(&spi->dev, + "scatter gather segment length is not a multiple of 4 - falling back to interrupt mode\n"); + return bcm2835_spi_transfer_one_irq(master, spi, tfr, cs); + } + + /* setup tx-DMA */ + ret = bcm2835_spi_prepare_sg(master, tfr, true); + if (ret) + return ret; + + /* start TX early */ + dma_async_issue_pending(master->dma_tx); + + /* mark as dma pending */ + bs->dma_pending = 1; + + /* set the DMA length */ + bcm2835_wr(bs, BCM2835_SPI_DLEN, tfr->len); + + /* start the HW */ + bcm2835_wr(bs, BCM2835_SPI_CS, + cs | BCM2835_SPI_CS_TA | BCM2835_SPI_CS_DMAEN); + + /* setup rx-DMA late - to run transfers while + * mapping of the rx buffers still takes place + * this saves 10us or more. + */ + ret = bcm2835_spi_prepare_sg(master, tfr, false); + if (ret) { + /* need to reset on errors */ + dmaengine_terminate_all(master->dma_tx); + bcm2835_spi_reset_hw(master); + return ret; + } + + /* start rx dma late */ + dma_async_issue_pending(master->dma_rx); + + /* wait for wakeup in framework */ + return 1; +} + +static bool bcm2835_spi_can_dma(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *tfr) +{ + /* only run for gpio_cs */ + if (!gpio_is_valid(spi->cs_gpio)) + return false; + + /* we start DMA efforts only on bigger transfers */ + if (tfr->len < BCM2835_SPI_DMA_MIN_LENGTH) + return false; + + /* BCM2835_SPI_DLEN has defined a max transfer size as + * 16 bit, so max is 65535 + * we can revisit this by using an alternative transfer + * method - ideally this would get done without any more + * interaction... + */ + if (tfr->len > 65535) { + dev_warn_once(&spi->dev, + "transfer size of %d too big for dma-transfer\n", + tfr->len); + return false; + } + + /* if we run rx/tx_buf with word aligned addresses then we are OK */ + if ((((size_t)tfr->rx_buf & 3) == 0) && + (((size_t)tfr->tx_buf & 3) == 0)) + return true; + + /* otherwise we only allow transfers within the same page + * to avoid wasting time on dma_mapping when it is not practical + */ + if (((size_t)tfr->tx_buf & PAGE_MASK) + tfr->len > PAGE_SIZE) { + dev_warn_once(&spi->dev, + "Unaligned spi tx-transfer bridging page\n"); + return false; + } + if (((size_t)tfr->rx_buf & PAGE_MASK) + tfr->len > PAGE_SIZE) { + dev_warn_once(&spi->dev, + "Unaligned spi tx-transfer bridging page\n"); + return false; + } + + /* return OK */ + return true; +} + +static void bcm2835_dma_release(struct spi_master *master) +{ + if (master->dma_tx) { + dmaengine_terminate_all(master->dma_tx); + dma_release_channel(master->dma_tx); + master->dma_tx = NULL; + } + if (master->dma_rx) { + dmaengine_terminate_all(master->dma_rx); + dma_release_channel(master->dma_rx); + master->dma_rx = NULL; + } +} + +static void bcm2835_dma_init(struct spi_master *master, struct device *dev) +{ + struct dma_slave_config slave_config; + const __be32 *addr; + dma_addr_t dma_reg_base; + int ret; + + /* base address in dma-space */ + addr = of_get_address(master->dev.of_node, 0, NULL, NULL); + if (!addr) { + dev_err(dev, "could not get DMA-register address - not using dma mode\n"); + goto err; + } + dma_reg_base = be32_to_cpup(addr); + + /* get tx/rx dma */ + master->dma_tx = dma_request_slave_channel(dev, "tx"); + if (!master->dma_tx) { + dev_err(dev, "no tx-dma configuration found - not using dma mode\n"); + goto err; + } + master->dma_rx = dma_request_slave_channel(dev, "rx"); + if (!master->dma_rx) { + dev_err(dev, "no rx-dma configuration found - not using dma mode\n"); + goto err_release; + } + + /* configure DMAs */ + slave_config.direction = DMA_MEM_TO_DEV; + slave_config.dst_addr = (u32)(dma_reg_base + BCM2835_SPI_FIFO); + slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; + + ret = dmaengine_slave_config(master->dma_tx, &slave_config); + if (ret) + goto err_config; + + slave_config.direction = DMA_DEV_TO_MEM; + slave_config.src_addr = (u32)(dma_reg_base + BCM2835_SPI_FIFO); + slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES; + + ret = dmaengine_slave_config(master->dma_rx, &slave_config); + if (ret) + goto err_config; + + /* all went well, so set can_dma */ + master->can_dma = bcm2835_spi_can_dma; + master->max_dma_len = 65535; /* limitation by BCM2835_SPI_DLEN */ + /* need to do TX AND RX DMA, so we need dummy buffers */ + master->flags = SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX; + + return; + +err_config: + dev_err(dev, "issue configuring dma: %d - not using DMA mode\n", + ret); +err_release: + bcm2835_dma_release(master); +err: + return; +} + +static int bcm2835_spi_transfer_one_poll(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *tfr, + u32 cs, + unsigned long xfer_time_us) +{ + struct bcm2835_spi *bs = spi_master_get_devdata(master); + unsigned long timeout; + + /* enable HW block without interrupts */ + bcm2835_wr(bs, BCM2835_SPI_CS, cs | BCM2835_SPI_CS_TA); + + /* fill in the fifo before timeout calculations + * if we are interrupted here, then the data is + * getting transferred by the HW while we are interrupted + */ + bcm2835_wr_fifo(bs); + + /* set the timeout */ + timeout = jiffies + BCM2835_SPI_POLLING_JIFFIES; + + /* loop until finished the transfer */ + while (bs->rx_len) { + /* fill in tx fifo with remaining data */ + bcm2835_wr_fifo(bs); + + /* read from fifo as much as possible */ + bcm2835_rd_fifo(bs); + + /* if there is still data pending to read + * then check the timeout + */ + if (bs->rx_len && time_after(jiffies, timeout)) { + dev_dbg_ratelimited(&spi->dev, + "timeout period reached: jiffies: %lu remaining tx/rx: %d/%d - falling back to interrupt mode\n", + jiffies - timeout, + bs->tx_len, bs->rx_len); + /* fall back to interrupt mode */ + return bcm2835_spi_transfer_one_irq(master, spi, + tfr, cs); + } + } + + /* Transfer complete - reset SPI HW */ + bcm2835_spi_reset_hw(master); + /* and return without waiting for completion */ + return 0; +} + static int bcm2835_spi_transfer_one(struct spi_master *master, struct spi_device *spi, s |