[U-Boot] [PATCH v3 1/6] spi: Add SiFive SPI driver
Jagan Teki
jagan at amarulasolutions.com
Mon Jul 15 08:31:57 UTC 2019
On Mon, Jul 8, 2019 at 9:40 AM Anup Patel <Anup.Patel at wdc.com> wrote:
>
> From: Bhargav Shah <bhargavshah1988 at gmail.com>
>
> This patch adds SiFive SPI driver. The driver is 100% DM driver
> and it determines input clock using clk framework.
>
> The SiFive SPI block is found on SiFive FU540 SOC and is used to
> access flash and MMC devices on SiFive Unleashed board.
>
> This driver implementation is inspired from the Linux SiFive SPI
> driver available in Linux-5.2 or higher and SiFive FSBL sources.
>
> Signed-off-by: Bhargav Shah <bhargavshah1988 at gmail.com>
> Signed-off-by: Anup Patel <anup.patel at wdc.com>
> Reviewed-by: Bin Meng <bmeng.cn at gmail.com>
> Tested-by: Bin Meng <bmeng.cn at gmail.com>
> ---
> drivers/spi/Kconfig | 8 +
> drivers/spi/Makefile | 1 +
> drivers/spi/spi-sifive.c | 403 +++++++++++++++++++++++++++++++++++++++
> 3 files changed, 412 insertions(+)
> create mode 100644 drivers/spi/spi-sifive.c
>
> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> index eb32f082fe..2712bad310 100644
> --- a/drivers/spi/Kconfig
> +++ b/drivers/spi/Kconfig
> @@ -224,6 +224,14 @@ config SANDBOX_SPI
> };
> };
>
> +config SIFIVE_SPI
> + bool "SiFive SPI driver"
> + help
> + This driver supports the SiFive SPI IP. If unsure say N.
> + Enable the SiFive SPI controller driver.
> +
> + The SiFive SPI controller driver is found on various SiFive SoCs.
> +
> config SPI_SUNXI
> bool "Allwinner SoC SPI controllers"
> help
> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
> index 8be9a4baa2..09a9d3697e 100644
> --- a/drivers/spi/Makefile
> +++ b/drivers/spi/Makefile
> @@ -49,6 +49,7 @@ obj-$(CONFIG_PL022_SPI) += pl022_spi.o
> obj-$(CONFIG_RENESAS_RPC_SPI) += renesas_rpc_spi.o
> obj-$(CONFIG_ROCKCHIP_SPI) += rk_spi.o
> obj-$(CONFIG_SANDBOX_SPI) += sandbox_spi.o
> +obj-$(CONFIG_SIFIVE_SPI) += spi-sifive.o
> obj-$(CONFIG_SPI_SUNXI) += spi-sunxi.o
> obj-$(CONFIG_SH_SPI) += sh_spi.o
> obj-$(CONFIG_SH_QSPI) += sh_qspi.o
> diff --git a/drivers/spi/spi-sifive.c b/drivers/spi/spi-sifive.c
> new file mode 100644
> index 0000000000..1186f6e8f5
> --- /dev/null
> +++ b/drivers/spi/spi-sifive.c
> @@ -0,0 +1,403 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright 2018 SiFive, Inc.
> + * Copyright 2019 Bhargav Shah <bhargavshah1988 at gmail.com>
> + *
> + * SiFive SPI controller driver (master mode only)
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <malloc.h>
> +#include <spi.h>
> +#include <asm/io.h>
> +#include <linux/log2.h>
> +#include <clk.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)
> +
> +struct sifive_spi {
> + void *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;
> + u32 num_cs;
> +};
> +
> +static void sifive_spi_write(struct sifive_spi *spi, int offset, u32 value)
> +{
> + writel(value, spi->regs + offset);
> +}
> +
> +static u32 sifive_spi_read(struct sifive_spi *spi, int offset)
> +{
> + return readl(spi->regs + offset);
> +}
Look like these are direct IO calls, so better call them directly.
> +
> +static void sifive_spi_prep_device(struct sifive_spi *spi,
> + struct dm_spi_slave_platdata *slave)
> +{
> + /* Update the chip select polarity */
> + if (slave->mode & SPI_CS_HIGH)
> + spi->cs_inactive &= ~BIT(slave->cs);
> + else
> + spi->cs_inactive |= BIT(slave->cs);
> + sifive_spi_write(spi, SIFIVE_SPI_REG_CSDEF, spi->cs_inactive);
> +
> + /* Select the correct device */
> + sifive_spi_write(spi, SIFIVE_SPI_REG_CSID, slave->cs);
> +}
> +
> +static int sifive_spi_set_cs(struct sifive_spi *spi,
> + struct dm_spi_slave_platdata *slave)
> +{
> + u32 cs_mode = SIFIVE_SPI_CSMODE_MODE_HOLD;
> +
> + if (slave->cs > spi->num_cs)
> + return -EINVAL;
> +
> + if (slave->mode & SPI_CS_HIGH)
> + cs_mode = SIFIVE_SPI_CSMODE_MODE_AUTO;
> +
> + sifive_spi_write(spi, SIFIVE_SPI_REG_CSMODE, cs_mode);
> +
> + return 0;
> +}
> +
> +static void sifive_spi_clear_cs(struct sifive_spi *spi)
> +{
> + sifive_spi_write(spi, SIFIVE_SPI_REG_CSMODE,
> + SIFIVE_SPI_CSMODE_MODE_AUTO);
> +}
This seems to be different CS and bus handling compared to existing spi drivers.
00: for claim or release - we enable and disable the bus
01: we have SPI_XFER_BEGIN flag ie where we activate the CS
02: we have SPI_XFER_END flag ie where we deactivae the CS
Look like the above code is managing all above points in calim and
release func calls, which is not a better approach interms of data
transfer b/w slave to bus. example the spi-nor do claim the bus before
flash operation but will call spi_xfer with device activate and
deactive flags (like BEGIN and END). so managing cs on spi_xfer can
make the data tranfer feasible, atleast from u-boot spi-nor or
spi-uclass point-of-view.
> +
> +static void sifive_spi_prep_transfer(struct sifive_spi *spi,
> + bool is_rx_xfer,
> + struct dm_spi_slave_platdata *slave)
> +{
> + u32 cr;
> +
> + /* Modify the SPI protocol mode */
> + cr = sifive_spi_read(spi, 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 (slave->mode & SPI_LSB_FIRST)
> + cr |= SIFIVE_SPI_FMT_ENDIAN;
> +
> + /* Number of wires ? */
> + cr &= ~SIFIVE_SPI_FMT_PROTO_MASK;
> + if ((slave->mode & SPI_TX_QUAD) || (slave->mode & SPI_RX_QUAD))
> + cr |= SIFIVE_SPI_FMT_PROTO_QUAD;
> + else if ((slave->mode & SPI_TX_DUAL) || (slave->mode & SPI_RX_DUAL))
> + cr |= SIFIVE_SPI_FMT_PROTO_DUAL;
> + else
> + cr |= SIFIVE_SPI_FMT_PROTO_SINGLE;
> +
> + /* SPI direction in/out ? */
> + cr &= ~SIFIVE_SPI_FMT_DIR;
> + if (!is_rx_xfer)
> + cr |= SIFIVE_SPI_FMT_DIR;
> +
> + sifive_spi_write(spi, SIFIVE_SPI_REG_FMT, cr);
> +}
> +
> +static void sifive_spi_rx(struct sifive_spi *spi, u8 *rx_ptr)
> +{
> + u32 data;
> +
> + do {
> + data = sifive_spi_read(spi, SIFIVE_SPI_REG_RXDATA);
> + } while (data & SIFIVE_SPI_RXDATA_EMPTY);
can be handle via wait_for_bit calls?
> +
> + 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 = sifive_spi_read(spi, SIFIVE_SPI_REG_TXDATA);
> + } while (data & SIFIVE_SPI_TXDATA_FULL);
can be handle via wait_for_bit calls?
> +
> + sifive_spi_write(spi, SIFIVE_SPI_REG_TXDATA, tx_data);
> +}
> +
> +static u8 sifive_spi_txrx(struct sifive_spi *spi, const u8 *tx_ptr)
> +{
> + u8 rx = 0;
> +
> + sifive_spi_tx(spi, tx_ptr);
> + sifive_spi_rx(spi, &rx);
> +
> + return rx;
> +}
> +
> +static int sifive_spi_claim_bus(struct udevice *dev)
> +{
> + int ret;
> + struct udevice *bus = dev->parent;
> + struct sifive_spi *spi = dev_get_priv(bus);
> + struct dm_spi_slave_platdata *slave = dev_get_parent_platdata(dev);
> +
> + sifive_spi_prep_device(spi, slave);
> +
> + ret = sifive_spi_set_cs(spi, slave);
> + if (ret)
> + return ret;
> +
> + return 0;
> +}
> +
> +static int sifive_spi_release_bus(struct udevice *dev)
> +{
> + struct sifive_spi *spi = dev_get_priv(dev->parent);
> +
> + sifive_spi_clear_cs(spi);
> +
> + return 0;
> +}
> +
> +static int sifive_spi_xfer(struct udevice *dev, unsigned int bitlen,
> + const void *dout, void *din, unsigned long flags)
> +{
> + struct udevice *bus = dev->parent;
> + struct sifive_spi *spi = dev_get_priv(bus);
> + struct dm_spi_slave_platdata *slave = dev_get_parent_platdata(dev);
> + const unsigned char *tx_ptr = dout;
> + unsigned char *rx_ptr = din;
> + u32 remaining_len;
> +
> + sifive_spi_prep_transfer(spi, true, slave);
> +
> + remaining_len = bitlen / 8;
> +
> + while (remaining_len) {
> + int n_words, tx_words, rx_words;
> +
> + n_words = min(remaining_len, spi->fifo_depth);
> +
> + /* Enqueue n_words for transmission */
> + if (tx_ptr) {
> + for (tx_words = 0; tx_words < n_words; ++tx_words) {
> + sifive_spi_txrx(spi, tx_ptr);
> + tx_ptr++;
> + }
> + }
> +
> + /* Read out all the data from the RX FIFO */
> + if (rx_ptr) {
> + for (rx_words = 0; rx_words < n_words; ++rx_words) {
> + *rx_ptr = sifive_spi_txrx(spi, NULL);
> + rx_ptr++;
> + }
> + }
> +
I don't see much code on sifive_spi_txrx except register read/writes
better handle all in this function itself.
> + remaining_len -= n_words;
> + }
> +
> + return 0;
> +}
> +
> +static int sifive_spi_set_speed(struct udevice *bus, uint speed)
> +{
> + struct sifive_spi *spi = dev_get_priv(bus);
> + 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;
> + sifive_spi_write(spi, SIFIVE_SPI_REG_SCKDIV, scale);
space here.
> + return 0;
> +}
> +
> +static int sifive_spi_set_mode(struct udevice *bus, uint mode)
> +{
> + struct sifive_spi *spi = dev_get_priv(bus);
> + u32 cr;
> +
> + /* Switch clock mode bits */
> + cr = sifive_spi_read(spi, 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;
> +
> + sifive_spi_write(spi, SIFIVE_SPI_REG_SCKMODE, cr);
> +
> + return 0;
> +}
> +
> +static int sifive_spi_cs_info(struct udevice *bus, uint cs,
> + struct spi_cs_info *info)
> +{
> + return 0;
> +}
Usually it has check for supported bus and cs number, if unsure better
remove this.
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