u-boot/drivers/spi/stm32_spi.c
Patrice Chotard a2a89b2e21 spi: stm32: Add Serial Peripheral Interface driver for STM32MP
Add SPI driver support for STM32MP SoCs family.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
2019-06-06 17:40:17 +02:00

615 lines
14 KiB
C

// 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,
};