[U-Boot] [PATCH v5 03/10] dm: spi: add BCM63xx SPI driver

Jagan Teki
2017-08-10T09:25:12Z

On Sun, Jul 30, 2017 at 5:43 PM, Álvaro Fernández Rojas
<noltari@gmail.com> wrote:
> This driver is a simplified version of linux/drivers/spi/spi-bcm63xx.c
>
> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
> Reviewed-by: Simon Glass <sjg@chromium.org>
> Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
> ---
> v5: Introduce changes suggested by Jagan Teki:
> - Use long structure instead of a custom bmips_spi_hw structure.
> - Define constants for each SPI core.
> v4: Introduce changes suggested by Jagan Teki:
> - Add data for each HW controller instead of having two separate configs.
> - Also check clock and reset returns as suggested by Simon Glass for HSSPI.
> v3: rename BCM6338 SPI driver to BCM6348
> switch to devfdt_get_addr_size_index()
> v2: no changes
>
> drivers/spi/Kconfig | 8 +
> drivers/spi/Makefile | 1 +
> drivers/spi/bcm63xx_spi.c | 434 ++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 443 insertions(+)
> create mode 100644 drivers/spi/bcm63xx_spi.c
>
> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> index 8a8e8e480f..511643607b 100644
> --- a/drivers/spi/Kconfig
> +++ b/drivers/spi/Kconfig
> @@ -40,6 +40,14 @@ config ATMEL_SPI
> many AT91 (ARM) chips. This driver can be used to access
> the SPI Flash, such as AT25DF321.
>
> +config BCM63XX_SPI
> + bool "BCM6348 SPI driver"
> + depends on ARCH_BMIPS
> + help
> + Enable the BCM6348/BCM6358 SPI driver. This driver can be used to
> + access the SPI NOR flash on platforms embedding these Broadcom
> + SPI cores.
> +
> config CADENCE_QSPI
> bool "Cadence QSPI driver"
> help
> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
> index 9f8b86de76..d9802dd8c3 100644
> --- a/drivers/spi/Makefile
> +++ b/drivers/spi/Makefile
> @@ -19,6 +19,7 @@ obj-$(CONFIG_ALTERA_SPI) += altera_spi.o
> obj-$(CONFIG_ATH79_SPI) += ath79_spi.o
> obj-$(CONFIG_ATMEL_DATAFLASH_SPI) += atmel_dataflash_spi.o
> obj-$(CONFIG_ATMEL_SPI) += atmel_spi.o
> +obj-$(CONFIG_BCM63XX_SPI) += bcm63xx_spi.o
> obj-$(CONFIG_CADENCE_QSPI) += cadence_qspi.o cadence_qspi_apb.o
> obj-$(CONFIG_CF_SPI) += cf_spi.o
> obj-$(CONFIG_DAVINCI_SPI) += davinci_spi.o
> diff --git a/drivers/spi/bcm63xx_spi.c b/drivers/spi/bcm63xx_spi.c
> new file mode 100644
> index 0000000000..904db2b7c7
> --- /dev/null
> +++ b/drivers/spi/bcm63xx_spi.c
> @@ -0,0 +1,434 @@
> +/*
> + * Copyright (C) 2017 Álvaro Fernández Rojas <noltari@gmail.com>
> + *
> + * Derived from linux/drivers/spi/spi-bcm63xx.c:
> + * Copyright (C) 2009-2012 Florian Fainelli <florian@openwrt.org>
> + * Copyright (C) 2010 Tanguy Bouzeloc <tanguy.bouzeloc@efixo.com>
> + *
> + * SPDX-License-Identifier: GPL-2.0+
> + */
> +
> +#include <common.h>
> +#include <clk.h>
> +#include <dm.h>
> +#include <spi.h>
> +#include <reset.h>
> +#include <asm/io.h>
> +
> +DECLARE_GLOBAL_DATA_PTR;
> +
> +/* BCM6348 SPI core */
> +#define SPI_6348_CLK 0x06
> +#define SPI_6348_CMD 0x00
> +#define SPI_6348_CTL 0x40
> +#define SPI_6348_CTL_SHIFT 6
> +#define SPI_6348_FILL 0x07
> +#define SPI_6348_IR_MASK 0x04
> +#define SPI_6348_IR_STAT 0x02
> +#define SPI_6348_RX 0x80
> +#define SPI_6348_RX_SIZE 0x3f
> +#define SPI_6348_TX 0x41
> +#define SPI_6348_TX_SIZE 0x3f
> +
> +/* BCM6358 SPI core */
> +#define SPI_6358_CLK 0x706
> +#define SPI_6358_CMD 0x700
> +#define SPI_6358_CTL 0x000
> +#define SPI_6358_CTL_SHIFT 14
> +#define SPI_6358_FILL 0x707
> +#define SPI_6358_IR_MASK 0x702
> +#define SPI_6358_IR_STAT 0x704
> +#define SPI_6358_RX 0x400
> +#define SPI_6358_RX_SIZE 0x220
> +#define SPI_6358_TX 0x002
> +#define SPI_6358_TX_SIZE 0x21e
> +
> +/* SPI Clock register */
> +#define SPI_CLK_SHIFT 0
> +#define SPI_CLK_20MHZ (0 << SPI_CLK_SHIFT)
> +#define SPI_CLK_0_391MHZ (1 << SPI_CLK_SHIFT)
> +#define SPI_CLK_0_781MHZ (2 << SPI_CLK_SHIFT)
> +#define SPI_CLK_1_563MHZ (3 << SPI_CLK_SHIFT)
> +#define SPI_CLK_3_125MHZ (4 << SPI_CLK_SHIFT)
> +#define SPI_CLK_6_250MHZ (5 << SPI_CLK_SHIFT)
> +#define SPI_CLK_12_50MHZ (6 << SPI_CLK_SHIFT)
> +#define SPI_CLK_25MHZ (7 << SPI_CLK_SHIFT)
> +#define SPI_CLK_MASK (7 << SPI_CLK_SHIFT)
> +#define SPI_CLK_SSOFF_SHIFT 3
> +#define SPI_CLK_SSOFF_2 (2 << SPI_CLK_SSOFF_SHIFT)
> +#define SPI_CLK_SSOFF_MASK (7 << SPI_CLK_SSOFF_SHIFT)
> +#define SPI_CLK_BSWAP_SHIFT 7
> +#define SPI_CLK_BSWAP_MASK (1 << SPI_CLK_BSWAP_SHIFT)
> +
> +/* SPI Command register */
> +#define SPI_CMD_OP_SHIFT 0
> +#define SPI_CMD_OP_START (0x3 << SPI_CMD_OP_SHIFT)
> +#define SPI_CMD_SLAVE_SHIFT 4
> +#define SPI_CMD_SLAVE_MASK (0xf << SPI_CMD_SLAVE_SHIFT)
> +#define SPI_CMD_PREPEND_SHIFT 8
> +#define SPI_CMD_PREPEND_BYTES 0xf
> +#define SPI_CMD_3WIRE_SHIFT 12
> +#define SPI_CMD_3WIRE_MASK (1 << SPI_CMD_3WIRE_SHIFT)
> +
> +/* SPI Control register */
> +#define SPI_CTL_TYPE_FD_RW 0
> +#define SPI_CTL_TYPE_HD_W 1
> +#define SPI_CTL_TYPE_HD_R 2
> +
> +/* SPI Interrupt registers */
> +#define SPI_IR_DONE_SHIFT 0
> +#define SPI_IR_DONE_MASK (1 << SPI_IR_DONE_SHIFT)
> +#define SPI_IR_RXOVER_SHIFT 1
> +#define SPI_IR_RXOVER_MASK (1 << SPI_IR_RXOVER_SHIFT)
> +#define SPI_IR_TXUNDER_SHIFT 2
> +#define SPI_IR_TXUNDER_MASK (1 << SPI_IR_TXUNDER_SHIFT)
> +#define SPI_IR_TXOVER_SHIFT 3
> +#define SPI_IR_TXOVER_MASK (1 << SPI_IR_TXOVER_SHIFT)
> +#define SPI_IR_RXUNDER_SHIFT 4
> +#define SPI_IR_RXUNDER_MASK (1 << SPI_IR_RXUNDER_SHIFT)
> +#define SPI_IR_CLEAR_MASK (SPI_IR_DONE_MASK |\
> + SPI_IR_RXOVER_MASK |\
> + SPI_IR_TXUNDER_MASK |\
> + SPI_IR_TXOVER_MASK |\
> + SPI_IR_RXUNDER_MASK)
> +
> +enum bcm63xx_regs_spi {
> + SPI_CLK,
> + SPI_CMD,
> + SPI_CTL,
> + SPI_CTL_SHIFT,
> + SPI_FILL,
> + SPI_IR_MASK,
> + SPI_IR_STAT,
> + SPI_RX,
> + SPI_RX_SIZE,
> + SPI_TX,
> + SPI_TX_SIZE,
> +};
> +
> +struct bcm63xx_spi_priv {
> + const unsigned long *regs;
> + void __iomem *base;
> + size_t tx_bytes;
> + uint8_t num_cs;
> +};
> +
> +#define SPI_CLK_CNT 8
> +static const unsigned bcm63xx_spi_freq_table[SPI_CLK_CNT][2] = {
> + { 25000000, SPI_CLK_25MHZ },
> + { 20000000, SPI_CLK_20MHZ },
> + { 12500000, SPI_CLK_12_50MHZ },
> + { 6250000, SPI_CLK_6_250MHZ },
> + { 3125000, SPI_CLK_3_125MHZ },
> + { 1563000, SPI_CLK_1_563MHZ },
> + { 781000, SPI_CLK_0_781MHZ },
> + { 391000, SPI_CLK_0_391MHZ }
> +};
> +
> +static int bcm63xx_spi_cs_info(struct udevice *bus, uint cs,
> + struct spi_cs_info *info)
> +{
> + struct bcm63xx_spi_priv *priv = dev_get_priv(bus);
> +
> + if (cs >= priv->num_cs) {
> + error("no cs %u\n", cs);
> + return -ENODEV;
> + }
> +
> + return 0;
> +}
> +
> +static int bcm63xx_spi_set_mode(struct udevice *bus, uint mode)
> +{
> + struct bcm63xx_spi_priv *priv = dev_get_priv(bus);
> + const unsigned long *regs = priv->regs;
> +
> + if (mode & SPI_LSB_FIRST)
> + setbits_8(priv->base + regs[SPI_CLK], SPI_CLK_BSWAP_MASK);
> + else
> + clrbits_8(priv->base + regs[SPI_CLK], SPI_CLK_BSWAP_MASK);
> +
> + return 0;
> +}
> +
> +static int bcm63xx_spi_set_speed(struct udevice *bus, uint speed)
> +{
> + struct bcm63xx_spi_priv *priv = dev_get_priv(bus);
> + const unsigned long *regs = priv->regs;
> + uint8_t clk_cfg;
> + int i;
> +
> + /* default to lowest clock configuration */
> + clk_cfg = SPI_CLK_0_391MHZ;
> +
> + /* find the closest clock configuration */
> + for (i = 0; i < SPI_CLK_CNT; i++) {
> + if (speed >= bcm63xx_spi_freq_table[i][0]) {
> + clk_cfg = bcm63xx_spi_freq_table[i][1];
> + break;
> + }
> + }
> +
> + /* write clock configuration */
> + clrsetbits_8(priv->base + regs[SPI_CLK],
> + SPI_CLK_SSOFF_MASK | SPI_CLK_MASK,
> + clk_cfg | SPI_CLK_SSOFF_2);
> +
> + return 0;
> +}
> +
> +/*
> + * BCM63xx SPI driver doesn't allow keeping CS active between transfers since
> + * they are HW controlled.
> + * However, it provides a mechanism to prepend write transfers prior to read
> + * transfers (with a maximum prepend of 15 bytes), which is usually enough for
> + * SPI-connected flashes since reading requires prepending a write transfer of
> + * 5 bytes.
> + *
> + * This implementation takes advantage of the prepend mechanism and combines
> + * multiple transfers into a single one where possible (single/multiple write
> + * transfer(s) followed by a final read/write transfer).
> + * However, it's not possible to buffer reads, which means that read transfers
> + * should always be done as the final ones.
> + * On the other hand, take into account that combining write transfers into
> + * a single one is just buffering and doesn't require prepend mechanism.
> + */
> +static int bcm63xx_spi_xfer(struct udevice *dev, unsigned int bitlen,
> + const void *dout, void *din, unsigned long flags)
> +{
> + struct bcm63xx_spi_priv *priv = dev_get_priv(dev->parent);
> + const unsigned long *regs = priv->regs;
> + size_t data_bytes = bitlen / 8;
> +
> + if (flags & SPI_XFER_BEGIN) {
> + /* clear prepends */
> + priv->tx_bytes = 0;
> +
> + /* initialize hardware */
> + writeb_be(0, priv->base + regs[SPI_IR_MASK]);
> + }
> +
> + if (din) {
> + /* buffering reads not possible since cs is hw controlled */
> + if (!(flags & SPI_XFER_END)) {
> + error("unable to buffer reads\n");
> + return -EINVAL;
> + }
> +
> + /* check rx size */
> + if (data_bytes > regs[SPI_RX_SIZE]) {
> + error("max rx bytes exceeded\n");
> + return -EMSGSIZE;
> + }
> + }
> +
> + if (dout) {
> + /* check tx size */
> + if (priv->tx_bytes + data_bytes > regs[SPI_TX_SIZE]) {
> + error("max tx bytes exceeded\n");
> + return -EMSGSIZE;
> + }
> +
> + /* copy tx data */
> + memcpy_toio(priv->base + regs[SPI_TX] + priv->tx_bytes,
> + dout, data_bytes);
> + priv->tx_bytes += data_bytes;
> + }
> +
> + if (flags & SPI_XFER_END) {
> + struct dm_spi_slave_platdata *plat =
> + dev_get_parent_platdata(dev);
> + uint16_t val;
> + uint8_t irq;
> +
> + /* determine control config */
> + if (dout && !din) {
> + /* buffered write transfers */
> + val = priv->tx_bytes;
> + val |= (SPI_CTL_TYPE_HD_W << regs[SPI_CTL_SHIFT]);
> + priv->tx_bytes = 0;
> + } else {
> + if (dout && din && (flags & SPI_XFER_ONCE)) {
> + /* full duplex read/write */
> + val = data_bytes;
> + val |= (SPI_CTL_TYPE_FD_RW <<
> + regs[SPI_CTL_SHIFT]);
> + priv->tx_bytes = 0;
> + } else {
> + /* prepended write transfer */
> + val = data_bytes;
> + val |= (SPI_CTL_TYPE_HD_R <<
> + regs[SPI_CTL_SHIFT]);
> + if (priv->tx_bytes > SPI_CMD_PREPEND_BYTES) {
> + error("max prepend bytes exceeded\n");
> + return -EMSGSIZE;
> + }
> + }
> + }
> +
> + if (regs[SPI_CTL_SHIFT] >= 8)
> + writew_be(val, priv->base + regs[SPI_CTL]);
> + else
> + writeb_be(val, priv->base + regs[SPI_CTL]);
> +
> + /* clear interrupts */
> + writeb_be(SPI_IR_CLEAR_MASK, priv->base + regs[SPI_IR_STAT]);
> +
> + /* issue the transfer */
> + val = SPI_CMD_OP_START;
> + val |= (plat->cs << SPI_CMD_SLAVE_SHIFT) & SPI_CMD_SLAVE_MASK;
> + val |= (priv->tx_bytes << SPI_CMD_PREPEND_SHIFT);
> + if (plat->mode & SPI_3WIRE)
> + val |= SPI_CMD_3WIRE_MASK;

Please use cmd instead of val to avoid confusion for previous register
reads use same val. And for issue the transfer why do we need to
update the mode here? usually transfer will be initiate with OP_START,
CS and prepend length right? and modes are usually altered during
.set_mode.

> + writew_be(val, priv->base + regs[SPI_CMD]);
> +
> + /* enable interrupts */
> + writeb_be(SPI_IR_DONE_MASK, priv->base + regs[SPI_IR_MASK]);
> +
> + do {
> + /* read interupts */
> + irq = readb_be(priv->base + regs[SPI_IR_STAT]);
> +
> + /* transfer completed */
> + if (irq & SPI_IR_DONE_MASK)
> + break;
> + } while (1);

This shouldn't be an infinite, try to use wait_for_bit with necessary timeout.

thanks!
--
Jagan Teki
Free Software Engineer | www.openedev.com
U-Boot, Linux | Upstream Maintainer
Hyderabad, India.