diff options
author | Neil Armstrong <narmstrong@baylibre.com> | 2017-05-23 16:39:33 +0300 |
---|---|---|
committer | Mark Brown <broonie@kernel.org> | 2017-05-24 20:19:25 +0300 |
commit | 454fa271bc4e71090ef55087027c3f8701fadc5b (patch) | |
tree | cde774dec7343b86a559d03ed0ab03e82a665b28 /drivers/spi/spi-meson-spicc.c | |
parent | 01a330da0c0ea2971be039f74a2288cbd2d17fbf (diff) | |
download | linux-454fa271bc4e71090ef55087027c3f8701fadc5b.tar.xz |
spi: Add Meson SPICC driver
The SPICC hardware block on the Amlogic SoCs is Communication oriented and
can do Full-Duplex 8- to 32-bit width SPI transfers up to 30MHz.
The current driver only supportd the PIO transfer mode since the DMA seems
broken on available hardware.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi-meson-spicc.c')
-rw-r--r-- | drivers/spi/spi-meson-spicc.c | 619 |
1 files changed, 619 insertions, 0 deletions
diff --git a/drivers/spi/spi-meson-spicc.c b/drivers/spi/spi-meson-spicc.c new file mode 100644 index 000000000000..7f8429635502 --- /dev/null +++ b/drivers/spi/spi-meson-spicc.c @@ -0,0 +1,619 @@ +/* + * Driver for Amlogic Meson SPI communication controller (SPICC) + * + * Copyright (C) BayLibre, SAS + * Author: Neil Armstrong <narmstrong@baylibre.com> + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <linux/bitfield.h> +#include <linux/clk.h> +#include <linux/device.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/spi/spi.h> +#include <linux/types.h> +#include <linux/interrupt.h> +#include <linux/reset.h> +#include <linux/gpio.h> + +/* + * The Meson SPICC controller could support DMA based transfers, but is not + * implemented by the vendor code, and while having the registers documentation + * it has never worked on the GXL Hardware. + * The PIO mode is the only mode implemented, and due to badly designed HW : + * - all transfers are cutted in 16 words burst because the FIFO hangs on + * TX underflow, and there is no TX "Half-Empty" interrupt, so we go by + * FIFO max size chunk only + * - CS management is dumb, and goes UP between every burst, so is really a + * "Data Valid" signal than a Chip Select, GPIO link should be used instead + * to have a CS go down over the full transfer + */ + +#define SPICC_MAX_FREQ 30000000 +#define SPICC_MAX_BURST 128 + +/* Register Map */ +#define SPICC_RXDATA 0x00 + +#define SPICC_TXDATA 0x04 + +#define SPICC_CONREG 0x08 +#define SPICC_ENABLE BIT(0) +#define SPICC_MODE_MASTER BIT(1) +#define SPICC_XCH BIT(2) +#define SPICC_SMC BIT(3) +#define SPICC_POL BIT(4) +#define SPICC_PHA BIT(5) +#define SPICC_SSCTL BIT(6) +#define SPICC_SSPOL BIT(7) +#define SPICC_DRCTL_MASK GENMASK(9, 8) +#define SPICC_DRCTL_IGNORE 0 +#define SPICC_DRCTL_FALLING 1 +#define SPICC_DRCTL_LOWLEVEL 2 +#define SPICC_CS_MASK GENMASK(13, 12) +#define SPICC_DATARATE_MASK GENMASK(18, 16) +#define SPICC_DATARATE_DIV4 0 +#define SPICC_DATARATE_DIV8 1 +#define SPICC_DATARATE_DIV16 2 +#define SPICC_DATARATE_DIV32 3 +#define SPICC_BITLENGTH_MASK GENMASK(24, 19) +#define SPICC_BURSTLENGTH_MASK GENMASK(31, 25) + +#define SPICC_INTREG 0x0c +#define SPICC_TE_EN BIT(0) /* TX FIFO Empty Interrupt */ +#define SPICC_TH_EN BIT(1) /* TX FIFO Half-Full Interrupt */ +#define SPICC_TF_EN BIT(2) /* TX FIFO Full Interrupt */ +#define SPICC_RR_EN BIT(3) /* RX FIFO Ready Interrupt */ +#define SPICC_RH_EN BIT(4) /* RX FIFO Half-Full Interrupt */ +#define SPICC_RF_EN BIT(5) /* RX FIFO Full Interrupt */ +#define SPICC_RO_EN BIT(6) /* RX FIFO Overflow Interrupt */ +#define SPICC_TC_EN BIT(7) /* Transfert Complete Interrupt */ + +#define SPICC_DMAREG 0x10 +#define SPICC_DMA_ENABLE BIT(0) +#define SPICC_TXFIFO_THRESHOLD_MASK GENMASK(5, 1) +#define SPICC_RXFIFO_THRESHOLD_MASK GENMASK(10, 6) +#define SPICC_READ_BURST_MASK GENMASK(14, 11) +#define SPICC_WRITE_BURST_MASK GENMASK(18, 15) +#define SPICC_DMA_URGENT BIT(19) +#define SPICC_DMA_THREADID_MASK GENMASK(25, 20) +#define SPICC_DMA_BURSTNUM_MASK GENMASK(31, 26) + +#define SPICC_STATREG 0x14 +#define SPICC_TE BIT(0) /* TX FIFO Empty Interrupt */ +#define SPICC_TH BIT(1) /* TX FIFO Half-Full Interrupt */ +#define SPICC_TF BIT(2) /* TX FIFO Full Interrupt */ +#define SPICC_RR BIT(3) /* RX FIFO Ready Interrupt */ +#define SPICC_RH BIT(4) /* RX FIFO Half-Full Interrupt */ +#define SPICC_RF BIT(5) /* RX FIFO Full Interrupt */ +#define SPICC_RO BIT(6) /* RX FIFO Overflow Interrupt */ +#define SPICC_TC BIT(7) /* Transfert Complete Interrupt */ + +#define SPICC_PERIODREG 0x18 +#define SPICC_PERIOD GENMASK(14, 0) /* Wait cycles */ + +#define SPICC_TESTREG 0x1c +#define SPICC_TXCNT_MASK GENMASK(4, 0) /* TX FIFO Counter */ +#define SPICC_RXCNT_MASK GENMASK(9, 5) /* RX FIFO Counter */ +#define SPICC_SMSTATUS_MASK GENMASK(12, 10) /* State Machine Status */ +#define SPICC_LBC_RO BIT(13) /* Loop Back Control Read-Only */ +#define SPICC_LBC_W1 BIT(14) /* Loop Back Control Write-Only */ +#define SPICC_SWAP_RO BIT(14) /* RX FIFO Data Swap Read-Only */ +#define SPICC_SWAP_W1 BIT(15) /* RX FIFO Data Swap Write-Only */ +#define SPICC_DLYCTL_RO_MASK GENMASK(20, 15) /* Delay Control Read-Only */ +#define SPICC_DLYCTL_W1_MASK GENMASK(21, 16) /* Delay Control Write-Only */ +#define SPICC_FIFORST_RO_MASK GENMASK(22, 21) /* FIFO Softreset Read-Only */ +#define SPICC_FIFORST_W1_MASK GENMASK(23, 22) /* FIFO Softreset Write-Only */ + +#define SPICC_DRADDR 0x20 /* Read Address of DMA */ + +#define SPICC_DWADDR 0x24 /* Write Address of DMA */ + +#define writel_bits_relaxed(mask, val, addr) \ + writel_relaxed((readl_relaxed(addr) & ~(mask)) | (val), addr) + +#define SPICC_BURST_MAX 16 +#define SPICC_FIFO_HALF 10 + +struct meson_spicc_device { + struct spi_master *master; + struct platform_device *pdev; + void __iomem *base; + struct clk *core; + struct spi_message *message; + struct spi_transfer *xfer; + u8 *tx_buf; + u8 *rx_buf; + unsigned int bytes_per_word; + unsigned long tx_remain; + unsigned long txb_remain; + unsigned long rx_remain; + unsigned long rxb_remain; + unsigned long xfer_remain; + bool is_burst_end; + bool is_last_burst; +}; + +static inline bool meson_spicc_txfull(struct meson_spicc_device *spicc) +{ + return !!FIELD_GET(SPICC_TF, + readl_relaxed(spicc->base + SPICC_STATREG)); +} + +static inline bool meson_spicc_rxready(struct meson_spicc_device *spicc) +{ + return FIELD_GET(SPICC_RH | SPICC_RR | SPICC_RF_EN, + readl_relaxed(spicc->base + SPICC_STATREG)); +} + +static inline u32 meson_spicc_pull_data(struct meson_spicc_device *spicc) +{ + unsigned int bytes = spicc->bytes_per_word; + unsigned int byte_shift = 0; + u32 data = 0; + u8 byte; + + while (bytes--) { + byte = *spicc->tx_buf++; + data |= (byte & 0xff) << byte_shift; + byte_shift += 8; + } + + spicc->tx_remain--; + return data; +} + +static inline void meson_spicc_push_data(struct meson_spicc_device *spicc, + u32 data) +{ + unsigned int bytes = spicc->bytes_per_word; + unsigned int byte_shift = 0; + u8 byte; + + while (bytes--) { + byte = (data >> byte_shift) & 0xff; + *spicc->rx_buf++ = byte; + byte_shift += 8; + } + + spicc->rx_remain--; +} + +static inline void meson_spicc_rx(struct meson_spicc_device *spicc) +{ + /* Empty RX FIFO */ + while (spicc->rx_remain && + meson_spicc_rxready(spicc)) + meson_spicc_push_data(spicc, + readl_relaxed(spicc->base + SPICC_RXDATA)); +} + +static inline void meson_spicc_tx(struct meson_spicc_device *spicc) +{ + /* Fill Up TX FIFO */ + while (spicc->tx_remain && + !meson_spicc_txfull(spicc)) + writel_relaxed(meson_spicc_pull_data(spicc), + spicc->base + SPICC_TXDATA); +} + +static inline u32 meson_spicc_setup_rx_irq(struct meson_spicc_device *spicc, + u32 irq_ctrl) +{ + if (spicc->rx_remain > SPICC_FIFO_HALF) + irq_ctrl |= SPICC_RH_EN; + else + irq_ctrl |= SPICC_RR_EN; + + return irq_ctrl; +} + +static inline void meson_spicc_setup_burst(struct meson_spicc_device *spicc, + unsigned int burst_len) +{ + /* Setup Xfer variables */ + spicc->tx_remain = burst_len; + spicc->rx_remain = burst_len; + spicc->xfer_remain -= burst_len * spicc->bytes_per_word; + spicc->is_burst_end = false; + if (burst_len < SPICC_BURST_MAX || !spicc->xfer_remain) + spicc->is_last_burst = true; + else + spicc->is_last_burst = false; + + /* Setup burst length */ + writel_bits_relaxed(SPICC_BURSTLENGTH_MASK, + FIELD_PREP(SPICC_BURSTLENGTH_MASK, + burst_len), + spicc->base + SPICC_CONREG); + + /* Fill TX FIFO */ + meson_spicc_tx(spicc); +} + +static irqreturn_t meson_spicc_irq(int irq, void *data) +{ + struct meson_spicc_device *spicc = (void *) data; + u32 ctrl = readl_relaxed(spicc->base + SPICC_INTREG); + u32 stat = readl_relaxed(spicc->base + SPICC_STATREG) & ctrl; + + ctrl &= ~(SPICC_RH_EN | SPICC_RR_EN); + + /* Empty RX FIFO */ + meson_spicc_rx(spicc); + + /* Enable TC interrupt since we transferred everything */ + if (!spicc->tx_remain && !spicc->rx_remain) { + spicc->is_burst_end = true; + + /* Enable TC interrupt */ + ctrl |= SPICC_TC_EN; + + /* Reload IRQ status */ + stat = readl_relaxed(spicc->base + SPICC_STATREG) & ctrl; + } + + /* Check transfer complete */ + if ((stat & SPICC_TC) && spicc->is_burst_end) { + unsigned int burst_len; + + /* Clear TC bit */ + writel_relaxed(SPICC_TC, spicc->base + SPICC_STATREG); + + /* Disable TC interrupt */ + ctrl &= ~SPICC_TC_EN; + + if (spicc->is_last_burst) { + /* Disable all IRQs */ + writel(0, spicc->base + SPICC_INTREG); + + spi_finalize_current_transfer(spicc->master); + + return IRQ_HANDLED; + } + + burst_len = min_t(unsigned int, + spicc->xfer_remain / spicc->bytes_per_word, + SPICC_BURST_MAX); + + /* Setup burst */ + meson_spicc_setup_burst(spicc, burst_len); + + /* Restart burst */ + writel_bits_relaxed(SPICC_XCH, SPICC_XCH, + spicc->base + SPICC_CONREG); + } + + /* Setup RX interrupt trigger */ + ctrl = meson_spicc_setup_rx_irq(spicc, ctrl); + + /* Reconfigure interrupts */ + writel(ctrl, spicc->base + SPICC_INTREG); + + return IRQ_HANDLED; +} + +static u32 meson_spicc_setup_speed(struct meson_spicc_device *spicc, u32 conf, + u32 speed) +{ + unsigned long parent, value; + unsigned int i, div; + + parent = clk_get_rate(spicc->core); + + /* Find closest inferior/equal possible speed */ + for (i = 0 ; i < 7 ; ++i) { + /* 2^(data_rate+2) */ + value = parent >> (i + 2); + + if (value <= speed) + break; + } + + /* If provided speed it lower than max divider, use max divider */ + if (i > 7) { + div = 7; + dev_warn_once(&spicc->pdev->dev, "unable to get close to speed %u\n", + speed); + } else + div = i; + + dev_dbg(&spicc->pdev->dev, "parent %lu, speed %u -> %lu (%u)\n", + parent, speed, value, div); + + conf &= ~SPICC_DATARATE_MASK; + conf |= FIELD_PREP(SPICC_DATARATE_MASK, div); + + return conf; +} + +static void meson_spicc_setup_xfer(struct meson_spicc_device *spicc, + struct spi_transfer *xfer) +{ + u32 conf, conf_orig; + + /* Read original configuration */ + conf = conf_orig = readl_relaxed(spicc->base + SPICC_CONREG); + + /* Select closest divider */ + conf = meson_spicc_setup_speed(spicc, conf, xfer->speed_hz); + + /* Setup word width */ + conf &= ~SPICC_BITLENGTH_MASK; + conf |= FIELD_PREP(SPICC_BITLENGTH_MASK, + (spicc->bytes_per_word << 3) - 1); + + /* Ignore if unchanged */ + if (conf != conf_orig) + writel_relaxed(conf, spicc->base + SPICC_CONREG); +} + +static int meson_spicc_transfer_one(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *xfer) +{ + struct meson_spicc_device *spicc = spi_master_get_devdata(master); + unsigned int burst_len; + u32 irq = 0; + + /* Store current transfer */ + spicc->xfer = xfer; + + /* Setup transfer parameters */ + spicc->tx_buf = (u8 *)xfer->tx_buf; + spicc->rx_buf = (u8 *)xfer->rx_buf; + spicc->xfer_remain = xfer->len; + + /* Pre-calculate word size */ + spicc->bytes_per_word = + DIV_ROUND_UP(spicc->xfer->bits_per_word, 8); + + /* Setup transfer parameters */ + meson_spicc_setup_xfer(spicc, xfer); + + burst_len = min_t(unsigned int, + spicc->xfer_remain / spicc->bytes_per_word, + SPICC_BURST_MAX); + + meson_spicc_setup_burst(spicc, burst_len); + + irq = meson_spicc_setup_rx_irq(spicc, irq); + + /* Start burst */ + writel_bits_relaxed(SPICC_XCH, SPICC_XCH, spicc->base + SPICC_CONREG); + + /* Enable interrupts */ + writel_relaxed(irq, spicc->base + SPICC_INTREG); + + return 1; +} + +static int meson_spicc_prepare_message(struct spi_master *master, + struct spi_message *message) +{ + struct meson_spicc_device *spicc = spi_master_get_devdata(master); + struct spi_device *spi = message->spi; + u32 conf = 0; + + /* Store current message */ + spicc->message = message; + + /* Enable Master */ + conf |= SPICC_ENABLE; + conf |= SPICC_MODE_MASTER; + + /* SMC = 0 */ + + /* Setup transfer mode */ + if (spi->mode & SPI_CPOL) + conf |= SPICC_POL; + else + conf &= ~SPICC_POL; + + if (spi->mode & SPI_CPHA) + conf |= SPICC_PHA; + else + conf &= ~SPICC_PHA; + + /* SSCTL = 0 */ + + if (spi->mode & SPI_CS_HIGH) + conf |= SPICC_SSPOL; + else + conf &= ~SPICC_SSPOL; + + if (spi->mode & SPI_READY) + conf |= FIELD_PREP(SPICC_DRCTL_MASK, SPICC_DRCTL_LOWLEVEL); + else + conf |= FIELD_PREP(SPICC_DRCTL_MASK, SPICC_DRCTL_IGNORE); + + /* Select CS */ + conf |= FIELD_PREP(SPICC_CS_MASK, spi->chip_select); + + /* Default Clock rate core/4 */ + + /* Default 8bit word */ + conf |= FIELD_PREP(SPICC_BITLENGTH_MASK, 8 - 1); + + writel_relaxed(conf, spicc->base + SPICC_CONREG); + + /* Setup no wait cycles by default */ + writel_relaxed(0, spicc->base + SPICC_PERIODREG); + + writel_bits_relaxed(BIT(24), BIT(24), spicc->base + SPICC_TESTREG); + + return 0; +} + +static int meson_spicc_unprepare_transfer(struct spi_master *master) +{ + struct meson_spicc_device *spicc = spi_master_get_devdata(master); + + /* Disable all IRQs */ + writel(0, spicc->base + SPICC_INTREG); + + /* Disable controller */ + writel_bits_relaxed(SPICC_ENABLE, 0, spicc->base + SPICC_CONREG); + + device_reset_optional(&spicc->pdev->dev); + + return 0; +} + +static int meson_spicc_setup(struct spi_device *spi) +{ + int ret = 0; + + if (!spi->controller_state) + spi->controller_state = spi_master_get_devdata(spi->master); + else if (gpio_is_valid(spi->cs_gpio)) + goto out_gpio; + else if (spi->cs_gpio == -ENOENT) + return 0; + + if (gpio_is_valid(spi->cs_gpio)) { + ret = gpio_request(spi->cs_gpio, dev_name(&spi->dev)); + if (ret) { + dev_err(&spi->dev, "failed to request cs gpio\n"); + return ret; + } + } + +out_gpio: + ret = gpio_direction_output(spi->cs_gpio, + !(spi->mode & SPI_CS_HIGH)); + + return ret; +} + +static void meson_spicc_cleanup(struct spi_device *spi) +{ + if (gpio_is_valid(spi->cs_gpio)) + gpio_free(spi->cs_gpio); + + spi->controller_state = NULL; +} + +static int meson_spicc_probe(struct platform_device *pdev) +{ + struct spi_master *master; + struct meson_spicc_device *spicc; + struct resource *res; + int ret, irq, rate; + + master = spi_alloc_master(&pdev->dev, sizeof(*spicc)); + if (!master) { + dev_err(&pdev->dev, "master allocation failed\n"); + return -ENOMEM; + } + spicc = spi_master_get_devdata(master); + spicc->master = master; + + spicc->pdev = pdev; + platform_set_drvdata(pdev, spicc); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + spicc->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(spicc->base)) { + dev_err(&pdev->dev, "io resource mapping failed\n"); + ret = PTR_ERR(spicc->base); + goto out_master; + } + + /* Disable all IRQs */ + writel_relaxed(0, spicc->base + SPICC_INTREG); + + irq = platform_get_irq(pdev, 0); + ret = devm_request_irq(&pdev->dev, irq, meson_spicc_irq, + 0, NULL, spicc); + if (ret) { + dev_err(&pdev->dev, "irq request failed\n"); + goto out_master; + } + + spicc->core = devm_clk_get(&pdev->dev, "core"); + if (IS_ERR(spicc->core)) { + dev_err(&pdev->dev, "core clock request failed\n"); + ret = PTR_ERR(spicc->core); + goto out_master; + } + + ret = clk_prepare_enable(spicc->core); + if (ret) { + dev_err(&pdev->dev, "core clock enable failed\n"); + goto out_master; + } + rate = clk_get_rate(spicc->core); + + device_reset_optional(&pdev->dev); + + master->num_chipselect = 4; + master->dev.of_node = pdev->dev.of_node; + master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_CS_HIGH; + master->bits_per_word_mask = SPI_BPW_MASK(32) | + SPI_BPW_MASK(24) | + SPI_BPW_MASK(16) | + SPI_BPW_MASK(8); + master->flags = (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX); + master->min_speed_hz = rate >> 9; + master->setup = meson_spicc_setup; + master->cleanup = meson_spicc_cleanup; + master->prepare_message = meson_spicc_prepare_message; + master->unprepare_transfer_hardware = meson_spicc_unprepare_transfer; + master->transfer_one = meson_spicc_transfer_one; + + /* Setup max rate according to the Meson GX datasheet */ + if ((rate >> 2) > SPICC_MAX_FREQ) + master->max_speed_hz = SPICC_MAX_FREQ; + else + master->max_speed_hz = rate >> 2; + + ret = devm_spi_register_master(&pdev->dev, master); + if (!ret) + return 0; + + dev_err(&pdev->dev, "spi master registration failed\n"); + +out_master: + spi_master_put(master); + + return ret; +} + +static int meson_spicc_remove(struct platform_device *pdev) +{ + struct meson_spicc_device *spicc = platform_get_drvdata(pdev); + + /* Disable SPI */ + writel(0, spicc->base + SPICC_CONREG); + + clk_disable_unprepare(spicc->core); + + return 0; +} + +static const struct of_device_id meson_spicc_of_match[] = { + { .compatible = "amlogic,meson-gx-spicc", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, meson_spicc_of_match); + +static struct platform_driver meson_spicc_driver = { + .probe = meson_spicc_probe, + .remove = meson_spicc_remove, + .driver = { + .name = "meson-spicc", + .of_match_table = of_match_ptr(meson_spicc_of_match), + }, +}; + +module_platform_driver(meson_spicc_driver); + +MODULE_DESCRIPTION("Meson SPI Communication Controller driver"); +MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>"); +MODULE_LICENSE("GPL"); |