diff options
Diffstat (limited to 'drivers/spi/spi-sifive.c')
| -rw-r--r-- | drivers/spi/spi-sifive.c | 522 |
1 files changed, 522 insertions, 0 deletions
diff --git a/drivers/spi/spi-sifive.c b/drivers/spi/spi-sifive.c new file mode 100644 index 0000000000..fbe80718e4 --- /dev/null +++ b/drivers/spi/spi-sifive.c @@ -0,0 +1,522 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright 2018 SiFive, Inc. + * Copyright 2019 Bhargav Shah <bhargavshah1988@gmail.com> + * + * SiFive SPI controller driver (master mode only) + */ + +#include <common.h> +#include <linux/clk.h> +#include <driver.h> +#include <init.h> +#include <errno.h> +#include <linux/reset.h> +#include <spi/spi.h> +#include <linux/spi/spi-mem.h> +#include <linux/bitops.h> +#include <clock.h> +#include <gpio.h> +#include <of_gpio.h> +#include <linux/bitfield.h> +#include <linux/iopoll.h> +#include <linux/log2.h> + +#define SIFIVE_SPI_MAX_CS 32 + +#define SIFIVE_SPI_DEFAULT_DEPTH 8 +#define SIFIVE_SPI_DEFAULT_BITS 8 + +/* register offsets */ +#define SIFIVE_SPI_REG_SCKDIV 0x00 /* Serial clock divisor */ +#define SIFIVE_SPI_REG_SCKMODE 0x04 /* Serial clock mode */ +#define SIFIVE_SPI_REG_CSID 0x10 /* Chip select ID */ +#define SIFIVE_SPI_REG_CSDEF 0x14 /* Chip select default */ +#define SIFIVE_SPI_REG_CSMODE 0x18 /* Chip select mode */ +#define SIFIVE_SPI_REG_DELAY0 0x28 /* Delay control 0 */ +#define SIFIVE_SPI_REG_DELAY1 0x2c /* Delay control 1 */ +#define SIFIVE_SPI_REG_FMT 0x40 /* Frame format */ +#define SIFIVE_SPI_REG_TXDATA 0x48 /* Tx FIFO data */ +#define SIFIVE_SPI_REG_RXDATA 0x4c /* Rx FIFO data */ +#define SIFIVE_SPI_REG_TXMARK 0x50 /* Tx FIFO watermark */ +#define SIFIVE_SPI_REG_RXMARK 0x54 /* Rx FIFO watermark */ +#define SIFIVE_SPI_REG_FCTRL 0x60 /* SPI flash interface control */ +#define SIFIVE_SPI_REG_FFMT 0x64 /* SPI flash instruction format */ +#define SIFIVE_SPI_REG_IE 0x70 /* Interrupt Enable Register */ +#define SIFIVE_SPI_REG_IP 0x74 /* Interrupt Pendings Register */ + +/* sckdiv bits */ +#define SIFIVE_SPI_SCKDIV_DIV_MASK 0xfffU + +/* sckmode bits */ +#define SIFIVE_SPI_SCKMODE_PHA BIT(0) +#define SIFIVE_SPI_SCKMODE_POL BIT(1) +#define SIFIVE_SPI_SCKMODE_MODE_MASK (SIFIVE_SPI_SCKMODE_PHA | \ + SIFIVE_SPI_SCKMODE_POL) + +/* csmode bits */ +#define SIFIVE_SPI_CSMODE_MODE_AUTO 0U +#define SIFIVE_SPI_CSMODE_MODE_HOLD 2U +#define SIFIVE_SPI_CSMODE_MODE_OFF 3U + +/* delay0 bits */ +#define SIFIVE_SPI_DELAY0_CSSCK(x) ((u32)(x)) +#define SIFIVE_SPI_DELAY0_CSSCK_MASK 0xffU +#define SIFIVE_SPI_DELAY0_SCKCS(x) ((u32)(x) << 16) +#define SIFIVE_SPI_DELAY0_SCKCS_MASK (0xffU << 16) + +/* delay1 bits */ +#define SIFIVE_SPI_DELAY1_INTERCS(x) ((u32)(x)) +#define SIFIVE_SPI_DELAY1_INTERCS_MASK 0xffU +#define SIFIVE_SPI_DELAY1_INTERXFR(x) ((u32)(x) << 16) +#define SIFIVE_SPI_DELAY1_INTERXFR_MASK (0xffU << 16) + +/* fmt bits */ +#define SIFIVE_SPI_FMT_PROTO_SINGLE 0U +#define SIFIVE_SPI_FMT_PROTO_DUAL 1U +#define SIFIVE_SPI_FMT_PROTO_QUAD 2U +#define SIFIVE_SPI_FMT_PROTO_MASK 3U +#define SIFIVE_SPI_FMT_ENDIAN BIT(2) +#define SIFIVE_SPI_FMT_DIR BIT(3) +#define SIFIVE_SPI_FMT_LEN(x) ((u32)(x) << 16) +#define SIFIVE_SPI_FMT_LEN_MASK (0xfU << 16) + +/* txdata bits */ +#define SIFIVE_SPI_TXDATA_DATA_MASK 0xffU +#define SIFIVE_SPI_TXDATA_FULL BIT(31) + +/* rxdata bits */ +#define SIFIVE_SPI_RXDATA_DATA_MASK 0xffU +#define SIFIVE_SPI_RXDATA_EMPTY BIT(31) + +/* ie and ip bits */ +#define SIFIVE_SPI_IP_TXWM BIT(0) +#define SIFIVE_SPI_IP_RXWM BIT(1) + +/* format protocol */ +#define SIFIVE_SPI_PROTO_QUAD 4 /* 4 lines I/O protocol transfer */ +#define SIFIVE_SPI_PROTO_DUAL 2 /* 2 lines I/O protocol transfer */ +#define SIFIVE_SPI_PROTO_SINGLE 1 /* 1 line I/O protocol transfer */ + +#define SPI_XFER_BEGIN 0x01 /* Assert CS before transfer */ +#define SPI_XFER_END 0x02 /* Deassert CS after transfer */ + +struct sifive_spi { + struct spi_controller ctlr; + void __iomem *regs; /* base address of the registers */ + u32 fifo_depth; + u32 bits_per_word; + u32 cs_inactive; /* Level of the CS pins when inactive*/ + u32 freq; + u8 fmt_proto; +}; + +static inline struct sifive_spi *to_sifive_spi(struct spi_controller *ctlr) +{ + return container_of(ctlr, struct sifive_spi, ctlr); +} + +static void sifive_spi_prep_device(struct sifive_spi *spi, + struct spi_device *spi_dev) +{ + /* Update the chip select polarity */ + if (spi_dev->mode & SPI_CS_HIGH) + spi->cs_inactive &= ~BIT(spi_dev->chip_select); + else + spi->cs_inactive |= BIT(spi_dev->chip_select); + writel(spi->cs_inactive, spi->regs + SIFIVE_SPI_REG_CSDEF); + + /* Select the correct device */ + writel(spi_dev->chip_select, spi->regs + SIFIVE_SPI_REG_CSID); +} + +static void sifive_spi_set_cs(struct sifive_spi *spi, + struct spi_device *spi_dev) +{ + u32 cs_mode = SIFIVE_SPI_CSMODE_MODE_HOLD; + + if (spi_dev->mode & SPI_CS_HIGH) + cs_mode = SIFIVE_SPI_CSMODE_MODE_AUTO; + + writel(cs_mode, spi->regs + SIFIVE_SPI_REG_CSMODE); +} + +static void sifive_spi_clear_cs(struct sifive_spi *spi) +{ + writel(SIFIVE_SPI_CSMODE_MODE_AUTO, spi->regs + SIFIVE_SPI_REG_CSMODE); +} + +static void sifive_spi_prep_transfer(struct sifive_spi *spi, + struct spi_device *spi_dev, + u8 *rx_ptr) +{ + u32 cr; + + /* Modify the SPI protocol mode */ + cr = readl(spi->regs + SIFIVE_SPI_REG_FMT); + + /* Bits per word ? */ + cr &= ~SIFIVE_SPI_FMT_LEN_MASK; + cr |= SIFIVE_SPI_FMT_LEN(spi->bits_per_word); + + /* LSB first? */ + cr &= ~SIFIVE_SPI_FMT_ENDIAN; + if (spi_dev->mode & SPI_LSB_FIRST) + cr |= SIFIVE_SPI_FMT_ENDIAN; + + /* Number of wires ? */ + cr &= ~SIFIVE_SPI_FMT_PROTO_MASK; + switch (spi->fmt_proto) { + case SIFIVE_SPI_PROTO_QUAD: + cr |= SIFIVE_SPI_FMT_PROTO_QUAD; + break; + case SIFIVE_SPI_PROTO_DUAL: + cr |= SIFIVE_SPI_FMT_PROTO_DUAL; + break; + default: + cr |= SIFIVE_SPI_FMT_PROTO_SINGLE; + break; + } + + /* SPI direction in/out ? */ + cr &= ~SIFIVE_SPI_FMT_DIR; + if (!rx_ptr) + cr |= SIFIVE_SPI_FMT_DIR; + + writel(cr, spi->regs + SIFIVE_SPI_REG_FMT); +} + +static void sifive_spi_rx(struct sifive_spi *spi, u8 *rx_ptr) +{ + u32 data; + + do { + data = readl(spi->regs + SIFIVE_SPI_REG_RXDATA); + } while (data & SIFIVE_SPI_RXDATA_EMPTY); + + if (rx_ptr) + *rx_ptr = data & SIFIVE_SPI_RXDATA_DATA_MASK; +} + +static void sifive_spi_tx(struct sifive_spi *spi, const u8 *tx_ptr) +{ + u32 data; + u8 tx_data = (tx_ptr) ? *tx_ptr & SIFIVE_SPI_TXDATA_DATA_MASK : + SIFIVE_SPI_TXDATA_DATA_MASK; + + do { + data = readl(spi->regs + SIFIVE_SPI_REG_TXDATA); + } while (data & SIFIVE_SPI_TXDATA_FULL); + + writel(tx_data, spi->regs + SIFIVE_SPI_REG_TXDATA); +} + +static int sifive_spi_wait(struct sifive_spi *spi, u32 mask) +{ + u32 val; + + return readl_poll_timeout(spi->regs + SIFIVE_SPI_REG_IP, val, + (val & mask) == mask, 100 * USEC_PER_MSEC); +} + +static int sifive_spi_transfer_one(struct spi_device *spi_dev, unsigned int nbytes, + const void *dout, void *din) +{ + struct sifive_spi *spi = to_sifive_spi(spi_dev->controller); + const u8 *tx_ptr = dout; + u8 *rx_ptr = din; + int ret; + + sifive_spi_prep_transfer(spi, spi_dev, rx_ptr); + + while (nbytes) { + unsigned int n_words = min(nbytes, spi->fifo_depth); + unsigned int tx_words, rx_words; + + /* Enqueue n_words for transmission */ + for (tx_words = 0; tx_words < n_words; tx_words++) { + if (!tx_ptr) + sifive_spi_tx(spi, NULL); + else + sifive_spi_tx(spi, tx_ptr++); + } + + if (rx_ptr) { + /* Wait for transmission + reception to complete */ + writel(n_words - 1, spi->regs + SIFIVE_SPI_REG_RXMARK); + ret = sifive_spi_wait(spi, SIFIVE_SPI_IP_RXWM); + if (ret) + return ret; + + /* Read out all the data from the RX FIFO */ + for (rx_words = 0; rx_words < n_words; rx_words++) + sifive_spi_rx(spi, rx_ptr++); + } else { + /* Wait for transmission to complete */ + ret = sifive_spi_wait(spi, SIFIVE_SPI_IP_TXWM); + if (ret) + return ret; + } + + nbytes -= n_words; + } + + return 0; +} + +static int sifive_spi_transfer(struct spi_device *spi_dev, struct spi_message *msg) +{ + struct spi_controller *ctlr = spi_dev->controller; + struct sifive_spi *spi = to_sifive_spi(ctlr); + struct spi_transfer *t; + int ret = 0; + + if (list_empty(&msg->transfers)) + return 0; + + msg->actual_length = 0; + + sifive_spi_prep_device(spi, spi_dev); + sifive_spi_set_cs(spi, spi_dev); + + dev_dbg(ctlr->dev, "transfer start actual_length=%i\n", msg->actual_length); + list_for_each_entry(t, &msg->transfers, transfer_list) { + dev_dbg(ctlr->dev, " xfer %p: len %u tx %p rx %p\n", + t, t->len, t->tx_buf, t->rx_buf); + + ret = sifive_spi_transfer_one(spi_dev, t->len, + t->tx_buf, t->rx_buf); + if (ret < 0) + goto out; + msg->actual_length += t->len; + } + dev_dbg(ctlr->dev, "transfer done actual_length=%i\n", msg->actual_length); + +out: + sifive_spi_clear_cs(spi); + return ret; +} + +static int sifive_spi_exec_op(struct spi_mem *mem, + const struct spi_mem_op *op) +{ + struct spi_device *spi_dev = mem->spi; + struct device *dev = &spi_dev->dev; + struct sifive_spi *spi = spi_controller_get_devdata(spi_dev->controller); + u8 opcode = op->cmd.opcode; + int ret; + + spi->fmt_proto = op->cmd.buswidth; + + sifive_spi_prep_device(spi, spi_dev); + sifive_spi_set_cs(spi, spi_dev); + + /* send the opcode */ + ret = sifive_spi_transfer_one(spi_dev, 1, &opcode, NULL); + if (ret < 0) { + dev_err(dev, "failed to xfer opcode\n"); + goto out; + } + + if (!op->addr.nbytes && !op->data.nbytes) + goto out; + + /* send the addr + dummy */ + if (op->addr.nbytes) { + int i, op_len = op->addr.nbytes + op->dummy.nbytes; + u8 *op_buf; + + op_buf = malloc(op_len); + if (!op_buf) { + ret = -ENOMEM; + goto out; + } + + /* fill address */ + for (i = 0; i < op->addr.nbytes; i++) + op_buf[i] = op->addr.val >> + (8 * (op->addr.nbytes - i - 1)); + + /* fill dummy */ + memset(op_buf + op->addr.nbytes, 0xff, op->dummy.nbytes); + + spi->fmt_proto = op->addr.buswidth; + + ret = sifive_spi_transfer_one(spi_dev, op_len, op_buf, NULL); + free(op_buf); + if (ret < 0) { + dev_err(dev, "failed to xfer addr + dummy\n"); + goto out; + } + } + + /* send/received the data */ + if (op->data.nbytes) { + const void *tx_buf = NULL; + void *rx_buf = NULL; + + if (op->data.dir == SPI_MEM_DATA_IN) + rx_buf = op->data.buf.in; + else + tx_buf = op->data.buf.out; + + spi->fmt_proto = op->data.buswidth; + + ret = sifive_spi_transfer_one(spi_dev, op->data.nbytes, + tx_buf, rx_buf); + if (ret) { + dev_err(dev, "failed to xfer data\n"); + goto out; + } + } + +out: + sifive_spi_clear_cs(spi); + return ret; +} + +static void sifive_spi_set_speed(struct sifive_spi *spi, uint speed) +{ + u32 scale; + + if (speed > spi->freq) + speed = spi->freq; + + /* Cofigure max speed */ + scale = (DIV_ROUND_UP(spi->freq >> 1, speed) - 1) + & SIFIVE_SPI_SCKDIV_DIV_MASK; + writel(scale, spi->regs + SIFIVE_SPI_REG_SCKDIV); +} + +static void sifive_spi_set_mode(struct sifive_spi *spi, uint mode) +{ + u32 cr; + + /* Switch clock mode bits */ + cr = readl(spi->regs + SIFIVE_SPI_REG_SCKMODE) & + ~SIFIVE_SPI_SCKMODE_MODE_MASK; + if (mode & SPI_CPHA) + cr |= SIFIVE_SPI_SCKMODE_PHA; + if (mode & SPI_CPOL) + cr |= SIFIVE_SPI_SCKMODE_POL; + + writel(cr, spi->regs + SIFIVE_SPI_REG_SCKMODE); +} + +static int sifive_spi_setup(struct spi_device *spi_dev) +{ + struct sifive_spi *spi = to_sifive_spi(spi_dev->controller); + + sifive_spi_set_mode(spi, spi_dev->mode); + sifive_spi_set_speed(spi, spi_dev->max_speed_hz); + + return 0; +} + +static void sifive_spi_init_hw(struct sifive_spi *spi) +{ + struct device *dev = spi->ctlr.dev; + u32 cs_bits; + + /* probe the number of CS lines */ + spi->cs_inactive = readl(spi->regs + SIFIVE_SPI_REG_CSDEF); + writel(0xffffffffU, spi->regs + SIFIVE_SPI_REG_CSDEF); + cs_bits = readl(spi->regs + SIFIVE_SPI_REG_CSDEF); + writel(spi->cs_inactive, spi->regs + SIFIVE_SPI_REG_CSDEF); + if (!cs_bits) { + dev_warn(dev, "Could not auto probe CS lines\n"); + return; + } + + spi->ctlr.num_chipselect = ilog2(cs_bits) + 1; + if (spi->ctlr.num_chipselect > SIFIVE_SPI_MAX_CS) { + dev_warn(dev, "Invalid number of spi slaves\n"); + return; + } + + /* Watermark interrupts are disabled by default */ + writel(0, spi->regs + SIFIVE_SPI_REG_IE); + + /* Default watermark FIFO threshold values */ + writel(1, spi->regs + SIFIVE_SPI_REG_TXMARK); + writel(0, spi->regs + SIFIVE_SPI_REG_RXMARK); + + /* Set CS/SCK Delays and Inactive Time to defaults */ + writel(SIFIVE_SPI_DELAY0_CSSCK(1) | SIFIVE_SPI_DELAY0_SCKCS(1), + spi->regs + SIFIVE_SPI_REG_DELAY0); + writel(SIFIVE_SPI_DELAY1_INTERCS(1) | SIFIVE_SPI_DELAY1_INTERXFR(0), + spi->regs + SIFIVE_SPI_REG_DELAY1); + + /* Exit specialized memory-mapped SPI flash mode */ + writel(0, spi->regs + SIFIVE_SPI_REG_FCTRL); +} + +static const struct spi_controller_mem_ops sifive_spi_mem_ops = { + .exec_op = sifive_spi_exec_op, +}; + +static void sifive_spi_dt_probe(struct sifive_spi *spi) +{ + struct device_node *node = spi->ctlr.dev->of_node; + + spi->fifo_depth = SIFIVE_SPI_DEFAULT_DEPTH; + of_property_read_u32(node, "sifive,fifo-depth", &spi->fifo_depth); + + spi->bits_per_word = SIFIVE_SPI_DEFAULT_BITS; + of_property_read_u32(node, "sifive,max-bits-per-word", &spi->bits_per_word); +} + +static int sifive_spi_probe(struct device *dev) +{ + struct sifive_spi *spi; + struct resource *iores; + struct spi_controller *ctlr; + struct clk *clkdev; + + iores = dev_request_mem_resource(dev, 0); + if (IS_ERR(iores)) + return PTR_ERR(iores); + + spi = xzalloc(sizeof(*spi)); + + spi->regs = IOMEM(iores->start); + if (!spi->regs) + return -ENODEV; + + ctlr = &spi->ctlr; + ctlr->dev = dev; + + ctlr->setup = sifive_spi_setup; + ctlr->transfer = sifive_spi_transfer; + ctlr->mem_ops = &sifive_spi_mem_ops; + + ctlr->bus_num = -1; + + spi_controller_set_devdata(ctlr, spi); + + sifive_spi_dt_probe(spi); + + clkdev = clk_get(dev, NULL); + if (IS_ERR(clkdev)) + return PTR_ERR(clkdev); + + spi->freq = clk_get_rate(clkdev); + + /* init the sifive spi hw */ + sifive_spi_init_hw(spi); + + return spi_register_master(ctlr); +} + +static const struct of_device_id sifive_spi_ids[] = { + { .compatible = "sifive,spi0" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, sifive_spi_ids); + +static struct driver sifive_spi_driver = { + .name = "sifive_spi", + .probe = sifive_spi_probe, + .of_compatible = sifive_spi_ids, +}; +coredevice_platform_driver(sifive_spi_driver); |