diff options
Diffstat (limited to 'drivers/spi/stm32_spi.c')
| -rw-r--r-- | drivers/spi/stm32_spi.c | 615 |
1 files changed, 615 insertions, 0 deletions
diff --git a/drivers/spi/stm32_spi.c b/drivers/spi/stm32_spi.c new file mode 100644 index 0000000000..34b217584d --- /dev/null +++ b/drivers/spi/stm32_spi.c @@ -0,0 +1,615 @@ +// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause +/* + * Copyright (C) 2019, STMicroelectronics - All Rights Reserved + * + * Driver for STMicroelectronics Serial peripheral interface (SPI) + */ +#include <common.h> +#include <clk.h> +#include <dm.h> +#include <errno.h> +#include <reset.h> +#include <spi.h> + +#include <asm/io.h> +#include <asm/gpio.h> +#include <linux/bitfield.h> +#include <linux/iopoll.h> + +/* STM32 SPI registers */ +#define STM32_SPI_CR1 0x00 +#define STM32_SPI_CR2 0x04 +#define STM32_SPI_CFG1 0x08 +#define STM32_SPI_CFG2 0x0C +#define STM32_SPI_SR 0x14 +#define STM32_SPI_IFCR 0x18 +#define STM32_SPI_TXDR 0x20 +#define STM32_SPI_RXDR 0x30 +#define STM32_SPI_I2SCFGR 0x50 + +/* STM32_SPI_CR1 bit fields */ +#define SPI_CR1_SPE BIT(0) +#define SPI_CR1_MASRX BIT(8) +#define SPI_CR1_CSTART BIT(9) +#define SPI_CR1_CSUSP BIT(10) +#define SPI_CR1_HDDIR BIT(11) +#define SPI_CR1_SSI BIT(12) + +/* STM32_SPI_CR2 bit fields */ +#define SPI_CR2_TSIZE GENMASK(15, 0) + +/* STM32_SPI_CFG1 bit fields */ +#define SPI_CFG1_DSIZE GENMASK(4, 0) +#define SPI_CFG1_DSIZE_MIN 3 +#define SPI_CFG1_FTHLV_SHIFT 5 +#define SPI_CFG1_FTHLV GENMASK(8, 5) +#define SPI_CFG1_MBR_SHIFT 28 +#define SPI_CFG1_MBR GENMASK(30, 28) +#define SPI_CFG1_MBR_MIN 0 +#define SPI_CFG1_MBR_MAX FIELD_GET(SPI_CFG1_MBR, SPI_CFG1_MBR) + +/* STM32_SPI_CFG2 bit fields */ +#define SPI_CFG2_COMM_SHIFT 17 +#define SPI_CFG2_COMM GENMASK(18, 17) +#define SPI_CFG2_MASTER BIT(22) +#define SPI_CFG2_LSBFRST BIT(23) +#define SPI_CFG2_CPHA BIT(24) +#define SPI_CFG2_CPOL BIT(25) +#define SPI_CFG2_SSM BIT(26) +#define SPI_CFG2_AFCNTR BIT(31) + +/* STM32_SPI_SR bit fields */ +#define SPI_SR_RXP BIT(0) +#define SPI_SR_TXP BIT(1) +#define SPI_SR_EOT BIT(3) +#define SPI_SR_TXTF BIT(4) +#define SPI_SR_OVR BIT(6) +#define SPI_SR_SUSP BIT(11) +#define SPI_SR_RXPLVL_SHIFT 13 +#define SPI_SR_RXPLVL GENMASK(14, 13) +#define SPI_SR_RXWNE BIT(15) + +/* STM32_SPI_IFCR bit fields */ +#define SPI_IFCR_ALL GENMASK(11, 3) + +/* STM32_SPI_I2SCFGR bit fields */ +#define SPI_I2SCFGR_I2SMOD BIT(0) + +#define MAX_CS_COUNT 4 + +/* SPI Master Baud Rate min/max divisor */ +#define STM32_MBR_DIV_MIN (2 << SPI_CFG1_MBR_MIN) +#define STM32_MBR_DIV_MAX (2 << SPI_CFG1_MBR_MAX) + +#define STM32_SPI_TIMEOUT_US 100000 + +/* SPI Communication mode */ +#define SPI_FULL_DUPLEX 0 +#define SPI_SIMPLEX_TX 1 +#define SPI_SIMPLEX_RX 2 +#define SPI_HALF_DUPLEX 3 + +struct stm32_spi_priv { + void __iomem *base; + struct clk clk; + struct reset_ctl rst_ctl; + struct gpio_desc cs_gpios[MAX_CS_COUNT]; + ulong bus_clk_rate; + unsigned int fifo_size; + unsigned int cur_bpw; + unsigned int cur_hz; + unsigned int cur_xferlen; /* current transfer length in bytes */ + int tx_len; /* number of data to be written in bytes */ + int rx_len; /* number of data to be read in bytes */ + const void *tx_buf; /* data to be written, or NULL */ + void *rx_buf; /* data to be read, or NULL */ + u32 cur_mode; + bool cs_high; +}; + +static void stm32_spi_write_txfifo(struct stm32_spi_priv *priv) +{ + while ((priv->tx_len > 0) && + (readl(priv->base + STM32_SPI_SR) & SPI_SR_TXP)) { + u32 offs = priv->cur_xferlen - priv->tx_len; + + if (priv->tx_len >= sizeof(u32) && + IS_ALIGNED((uintptr_t)(priv->tx_buf + offs), sizeof(u32))) { + const u32 *tx_buf32 = (const u32 *)(priv->tx_buf + offs); + + writel(*tx_buf32, priv->base + STM32_SPI_TXDR); + priv->tx_len -= sizeof(u32); + } else if (priv->tx_len >= sizeof(u16) && + IS_ALIGNED((uintptr_t)(priv->tx_buf + offs), sizeof(u16))) { + const u16 *tx_buf16 = (const u16 *)(priv->tx_buf + offs); + + writew(*tx_buf16, priv->base + STM32_SPI_TXDR); + priv->tx_len -= sizeof(u16); + } else { + const u8 *tx_buf8 = (const u8 *)(priv->tx_buf + offs); + + writeb(*tx_buf8, priv->base + STM32_SPI_TXDR); + priv->tx_len -= sizeof(u8); + } + } + + debug("%s: %d bytes left\n", __func__, priv->tx_len); +} + +static void stm32_spi_read_rxfifo(struct stm32_spi_priv *priv) +{ + u32 sr = readl(priv->base + STM32_SPI_SR); + u32 rxplvl = (sr & SPI_SR_RXPLVL) >> SPI_SR_RXPLVL_SHIFT; + + while ((priv->rx_len > 0) && + ((sr & SPI_SR_RXP) || + ((sr & SPI_SR_EOT) && ((sr & SPI_SR_RXWNE) || (rxplvl > 0))))) { + u32 offs = priv->cur_xferlen - priv->rx_len; + + if (IS_ALIGNED((uintptr_t)(priv->rx_buf + offs), sizeof(u32)) && + (priv->rx_len >= sizeof(u32) || (sr & SPI_SR_RXWNE))) { + u32 *rx_buf32 = (u32 *)(priv->rx_buf + offs); + + *rx_buf32 = readl(priv->base + STM32_SPI_RXDR); + priv->rx_len -= sizeof(u32); + } else if (IS_ALIGNED((uintptr_t)(priv->rx_buf + offs), sizeof(u16)) && + (priv->rx_len >= sizeof(u16) || + (!(sr & SPI_SR_RXWNE) && + (rxplvl >= 2 || priv->cur_bpw > 8)))) { + u16 *rx_buf16 = (u16 *)(priv->rx_buf + offs); + + *rx_buf16 = readw(priv->base + STM32_SPI_RXDR); + priv->rx_len -= sizeof(u16); + } else { + u8 *rx_buf8 = (u8 *)(priv->rx_buf + offs); + + *rx_buf8 = readb(priv->base + STM32_SPI_RXDR); + priv->rx_len -= sizeof(u8); + } + + sr = readl(priv->base + STM32_SPI_SR); + rxplvl = (sr & SPI_SR_RXPLVL) >> SPI_SR_RXPLVL_SHIFT; + } + + debug("%s: %d bytes left\n", __func__, priv->rx_len); +} + +static int stm32_spi_enable(struct stm32_spi_priv *priv) +{ + debug("%s\n", __func__); + + /* Enable the SPI hardware */ + setbits_le32(priv->base + STM32_SPI_CR1, SPI_CR1_SPE); + + return 0; +} + +static int stm32_spi_disable(struct stm32_spi_priv *priv) +{ + debug("%s\n", __func__); + + /* Disable the SPI hardware */ + clrbits_le32(priv->base + STM32_SPI_CR1, SPI_CR1_SPE); + + return 0; +} + +static int stm32_spi_claim_bus(struct udevice *slave) +{ + struct udevice *bus = dev_get_parent(slave); + struct stm32_spi_priv *priv = dev_get_priv(bus); + + debug("%s\n", __func__); + + /* Enable the SPI hardware */ + return stm32_spi_enable(priv); +} + +static int stm32_spi_release_bus(struct udevice *slave) +{ + struct udevice *bus = dev_get_parent(slave); + struct stm32_spi_priv *priv = dev_get_priv(bus); + + debug("%s\n", __func__); + + /* Disable the SPI hardware */ + return stm32_spi_disable(priv); +} + +static void stm32_spi_stopxfer(struct udevice *dev) +{ + struct stm32_spi_priv *priv = dev_get_priv(dev); + u32 cr1, sr; + int ret; + + debug("%s\n", __func__); + + cr1 = readl(priv->base + STM32_SPI_CR1); + + if (!(cr1 & SPI_CR1_SPE)) + return; + + /* Wait on EOT or suspend the flow */ + ret = readl_poll_timeout(priv->base + STM32_SPI_SR, sr, + !(sr & SPI_SR_EOT), 100000); + if (ret < 0) { + if (cr1 & SPI_CR1_CSTART) { + writel(cr1 | SPI_CR1_CSUSP, priv->base + STM32_SPI_CR1); + if (readl_poll_timeout(priv->base + STM32_SPI_SR, + sr, !(sr & SPI_SR_SUSP), + 100000) < 0) + dev_err(dev, "Suspend request timeout\n"); + } + } + + /* clear status flags */ + setbits_le32(priv->base + STM32_SPI_IFCR, SPI_IFCR_ALL); +} + +static int stm32_spi_set_cs(struct udevice *dev, unsigned int cs, bool enable) +{ + struct stm32_spi_priv *priv = dev_get_priv(dev); + + debug("%s: cs=%d enable=%d\n", __func__, cs, enable); + + if (cs >= MAX_CS_COUNT) + return -ENODEV; + + if (!dm_gpio_is_valid(&priv->cs_gpios[cs])) + return -EINVAL; + + if (priv->cs_high) + enable = !enable; + + return dm_gpio_set_value(&priv->cs_gpios[cs], enable ? 1 : 0); +} + +static int stm32_spi_set_mode(struct udevice *bus, uint mode) +{ + struct stm32_spi_priv *priv = dev_get_priv(bus); + u32 cfg2_clrb = 0, cfg2_setb = 0; + + debug("%s: mode=%d\n", __func__, mode); + + if (mode & SPI_CPOL) + cfg2_setb |= SPI_CFG2_CPOL; + else + cfg2_clrb |= SPI_CFG2_CPOL; + + if (mode & SPI_CPHA) + cfg2_setb |= SPI_CFG2_CPHA; + else + cfg2_clrb |= SPI_CFG2_CPHA; + + if (mode & SPI_LSB_FIRST) + cfg2_setb |= SPI_CFG2_LSBFRST; + else + cfg2_clrb |= SPI_CFG2_LSBFRST; + + if (cfg2_clrb || cfg2_setb) + clrsetbits_le32(priv->base + STM32_SPI_CFG2, + cfg2_clrb, cfg2_setb); + + if (mode & SPI_CS_HIGH) + priv->cs_high = true; + else + priv->cs_high = false; + return 0; +} + +static int stm32_spi_set_fthlv(struct udevice *dev, u32 xfer_len) +{ + struct stm32_spi_priv *priv = dev_get_priv(dev); + u32 fthlv, half_fifo; + + /* data packet should not exceed 1/2 of fifo space */ + half_fifo = (priv->fifo_size / 2); + + /* data_packet should not exceed transfer length */ + fthlv = (half_fifo > xfer_len) ? xfer_len : half_fifo; + + /* align packet size with data registers access */ + fthlv -= (fthlv % 4); + + if (!fthlv) + fthlv = 1; + clrsetbits_le32(priv->base + STM32_SPI_CFG1, SPI_CFG1_FTHLV, + (fthlv - 1) << SPI_CFG1_FTHLV_SHIFT); + + return 0; +} + +static int stm32_spi_set_speed(struct udevice *bus, uint hz) +{ + struct stm32_spi_priv *priv = dev_get_priv(bus); + u32 div, mbrdiv; + + debug("%s: hz=%d\n", __func__, hz); + + if (priv->cur_hz == hz) + return 0; + + div = DIV_ROUND_UP(priv->bus_clk_rate, hz); + + if (div < STM32_MBR_DIV_MIN || + div > STM32_MBR_DIV_MAX) + return -EINVAL; + + /* Determine the first power of 2 greater than or equal to div */ + if (div & (div - 1)) + mbrdiv = fls(div); + else + mbrdiv = fls(div) - 1; + + if ((mbrdiv - 1) < 0) + return -EINVAL; + + clrsetbits_le32(priv->base + STM32_SPI_CFG1, SPI_CFG1_MBR, + (mbrdiv - 1) << SPI_CFG1_MBR_SHIFT); + + priv->cur_hz = hz; + + return 0; +} + +static int stm32_spi_xfer(struct udevice *slave, unsigned int bitlen, + const void *dout, void *din, unsigned long flags) +{ + struct udevice *bus = dev_get_parent(slave); + struct dm_spi_slave_platdata *slave_plat; + struct stm32_spi_priv *priv = dev_get_priv(bus); + u32 sr; + u32 ifcr = 0; + u32 xferlen; + u32 mode; + int xfer_status = 0; + + xferlen = bitlen / 8; + + if (xferlen <= SPI_CR2_TSIZE) + writel(xferlen, priv->base + STM32_SPI_CR2); + else + return -EMSGSIZE; + + priv->tx_buf = dout; + priv->rx_buf = din; + priv->tx_len = priv->tx_buf ? bitlen / 8 : 0; + priv->rx_len = priv->rx_buf ? bitlen / 8 : 0; + + mode = SPI_FULL_DUPLEX; + if (!priv->tx_buf) + mode = SPI_SIMPLEX_RX; + else if (!priv->rx_buf) + mode = SPI_SIMPLEX_TX; + + if (priv->cur_xferlen != xferlen || priv->cur_mode != mode) { + priv->cur_mode = mode; + priv->cur_xferlen = xferlen; + + /* Disable the SPI hardware to unlock CFG1/CFG2 registers */ + stm32_spi_disable(priv); + + clrsetbits_le32(priv->base + STM32_SPI_CFG2, SPI_CFG2_COMM, + mode << SPI_CFG2_COMM_SHIFT); + + stm32_spi_set_fthlv(bus, xferlen); + + /* Enable the SPI hardware */ + stm32_spi_enable(priv); + } + + debug("%s: priv->tx_len=%d priv->rx_len=%d\n", __func__, + priv->tx_len, priv->rx_len); + + slave_plat = dev_get_parent_platdata(slave); + if (flags & SPI_XFER_BEGIN) + stm32_spi_set_cs(bus, slave_plat->cs, false); + + /* Be sure to have data in fifo before starting data transfer */ + if (priv->tx_buf) + stm32_spi_write_txfifo(priv); + + setbits_le32(priv->base + STM32_SPI_CR1, SPI_CR1_CSTART); + + while (1) { + sr = readl(priv->base + STM32_SPI_SR); + + if (sr & SPI_SR_OVR) { + dev_err(bus, "Overrun: RX data lost\n"); + xfer_status = -EIO; + break; + } + + if (sr & SPI_SR_SUSP) { + dev_warn(bus, "System too slow is limiting data throughput\n"); + + if (priv->rx_buf && priv->rx_len > 0) + stm32_spi_read_rxfifo(priv); + + ifcr |= SPI_SR_SUSP; + } + + if (sr & SPI_SR_TXTF) + ifcr |= SPI_SR_TXTF; + + if (sr & SPI_SR_TXP) + if (priv->tx_buf && priv->tx_len > 0) + stm32_spi_write_txfifo(priv); + + if (sr & SPI_SR_RXP) + if (priv->rx_buf && priv->rx_len > 0) + stm32_spi_read_rxfifo(priv); + + if (sr & SPI_SR_EOT) { + if (priv->rx_buf && priv->rx_len > 0) + stm32_spi_read_rxfifo(priv); + break; + } + + writel(ifcr, priv->base + STM32_SPI_IFCR); + } + + /* clear status flags */ + setbits_le32(priv->base + STM32_SPI_IFCR, SPI_IFCR_ALL); + stm32_spi_stopxfer(bus); + + if (flags & SPI_XFER_END) + stm32_spi_set_cs(bus, slave_plat->cs, true); + + return xfer_status; +} + +static int stm32_spi_get_fifo_size(struct udevice *dev) +{ + struct stm32_spi_priv *priv = dev_get_priv(dev); + u32 count = 0; + + stm32_spi_enable(priv); + + while (readl(priv->base + STM32_SPI_SR) & SPI_SR_TXP) + writeb(++count, priv->base + STM32_SPI_TXDR); + + stm32_spi_disable(priv); + + debug("%s %d x 8-bit fifo size\n", __func__, count); + + return count; +} + +static int stm32_spi_probe(struct udevice *dev) +{ + struct stm32_spi_priv *priv = dev_get_priv(dev); + unsigned long clk_rate; + int ret; + int i; + + priv->base = dev_remap_addr(dev); + if (!priv->base) + return -EINVAL; + + /* enable clock */ + ret = clk_get_by_index(dev, 0, &priv->clk); + if (ret < 0) + return ret; + + ret = clk_enable(&priv->clk); + if (ret < 0) + return ret; + + clk_rate = clk_get_rate(&priv->clk); + if (!clk_rate) { + ret = -EINVAL; + goto clk_err; + } + + priv->bus_clk_rate = clk_rate; + + /* perform reset */ + ret = reset_get_by_index(dev, 0, &priv->rst_ctl); + if (ret < 0) + goto clk_err; + + reset_assert(&priv->rst_ctl); + udelay(2); + reset_deassert(&priv->rst_ctl); + + ret = gpio_request_list_by_name(dev, "cs-gpios", priv->cs_gpios, + ARRAY_SIZE(priv->cs_gpios), 0); + if (ret < 0) { + pr_err("Can't get %s cs gpios: %d", dev->name, ret); + goto reset_err; + } + + priv->fifo_size = stm32_spi_get_fifo_size(dev); + + priv->cur_mode = SPI_FULL_DUPLEX; + priv->cur_xferlen = 0; + priv->cur_bpw = SPI_DEFAULT_WORDLEN; + clrsetbits_le32(priv->base + STM32_SPI_CFG1, SPI_CFG1_DSIZE, + priv->cur_bpw - 1); + + for (i = 0; i < ARRAY_SIZE(priv->cs_gpios); i++) { + if (!dm_gpio_is_valid(&priv->cs_gpios[i])) + continue; + + dm_gpio_set_dir_flags(&priv->cs_gpios[i], + GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE); + } + + /* Ensure I2SMOD bit is kept cleared */ + clrbits_le32(priv->base + STM32_SPI_I2SCFGR, SPI_I2SCFGR_I2SMOD); + + /* + * - SS input value high + * - transmitter half duplex direction + * - automatic communication suspend when RX-Fifo is full + */ + setbits_le32(priv->base + STM32_SPI_CR1, + SPI_CR1_SSI | SPI_CR1_HDDIR | SPI_CR1_MASRX); + + /* + * - Set the master mode (default Motorola mode) + * - Consider 1 master/n slaves configuration and + * SS input value is determined by the SSI bit + * - keep control of all associated GPIOs + */ + setbits_le32(priv->base + STM32_SPI_CFG2, + SPI_CFG2_MASTER | SPI_CFG2_SSM | SPI_CFG2_AFCNTR); + + return 0; + +reset_err: + reset_free(&priv->rst_ctl); + +clk_err: + clk_disable(&priv->clk); + clk_free(&priv->clk); + + return ret; +}; + +static int stm32_spi_remove(struct udevice *dev) +{ + struct stm32_spi_priv *priv = dev_get_priv(dev); + int ret; + + stm32_spi_stopxfer(dev); + stm32_spi_disable(priv); + + ret = reset_assert(&priv->rst_ctl); + if (ret < 0) + return ret; + + reset_free(&priv->rst_ctl); + + ret = clk_disable(&priv->clk); + if (ret < 0) + return ret; + + clk_free(&priv->clk); + + return ret; +}; + +static const struct dm_spi_ops stm32_spi_ops = { + .claim_bus = stm32_spi_claim_bus, + .release_bus = stm32_spi_release_bus, + .set_mode = stm32_spi_set_mode, + .set_speed = stm32_spi_set_speed, + .xfer = stm32_spi_xfer, +}; + +static const struct udevice_id stm32_spi_ids[] = { + { .compatible = "st,stm32h7-spi", }, + { } +}; + +U_BOOT_DRIVER(stm32_spi) = { + .name = "stm32_spi", + .id = UCLASS_SPI, + .of_match = stm32_spi_ids, + .ops = &stm32_spi_ops, + .priv_auto_alloc_size = sizeof(struct stm32_spi_priv), + .probe = stm32_spi_probe, + .remove = stm32_spi_remove, +}; |