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

Jagan Teki
2017-06-07T17:29:52Z

On Wed, Jun 7, 2017 at 9:05 PM, Álvaro Fernández Rojas
<noltari@gmail.com> wrote:
> Hi Jagan,
>
> El 7/6/17 a las 9:35, Jagan Teki escribió:
>> On Fri, May 19, 2017 at 12:59 AM, Álvaro Fernández Rojas
>> <noltari@gmail.com> wrote:
>>> This driver is a simplified version of linux/drivers/spi/spi-bcm63xx.c
>>> Instead of supporting both HW revisions of the controller in a single build,
>>> support has been split by the selected config to save space.
>>>
>>> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
>>> ---
>>> drivers/spi/Kconfig | 23 +++
>>> drivers/spi/Makefile | 1 +
>>> drivers/spi/bcm63xx_spi.c | 404 ++++++++++++++++++++++++++++++++++++++++++++++
>>> 3 files changed, 428 insertions(+)
>>> create mode 100644 drivers/spi/bcm63xx_spi.c
>>>
>>> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
>>> index a00d401..d458dd7 100644
>>> --- a/drivers/spi/Kconfig
>>> +++ b/drivers/spi/Kconfig
>>> @@ -43,6 +43,29 @@ config ATMEL_SPI
>>> many AT32 (AVR32) and AT91 (ARM) chips. This driver can be
>>> used to access the SPI Flash, such as AT25DF321.
>>>
>>> +choice
>>> + prompt "BCM63xx SPI driver"
>>> + depends on ARCH_BMIPS
>>> + optional
>>> +
>>> +config BCM6338_SPI
>>> + bool "BCM6338 SPI driver"
>>> + select SPI_MAX_WRITE_CMD_BYTES
>>> + help
>>> + Enable the BCM6338 SPI driver. This driver can be used to
>>> + access the SPI NOR flash on platforms embedding this Broadcom
>>> + SPI core.
>>> +
>>> +config BCM6358_SPI
>>> + bool "BCM6358 SPI driver"
>>> + select SPI_MAX_WRITE_CMD_BYTES
>>> + help
>>> + Enable the BCM6358 SPI driver. This driver can be used to
>>> + access the SPI NOR flash on platforms embedding this Broadcom
>>> + SPI core.
>>> +
>>> +endchoice
>>> +
>>> config CADENCE_QSPI
>>> bool "Cadence QSPI driver"
>>> help
>>> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
>>> index c090562..c9ba648 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-$(CONFIG_BCM6338_SPI)$(CONFIG_BCM6358_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 0000000..6e64607
>>> --- /dev/null
>>> +++ b/drivers/spi/bcm63xx_spi.c
>>> @@ -0,0 +1,404 @@
>>> +/*
>>> + * 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;
>>> +
>>> +#if defined(CONFIG_BCM6338_SPI)
>>> +
>>> +# define SPI_DT_ID "brcm,bcm6338-spi"
>>> +
>>> +/* SPI Command register */
>>> +# define SPI_CMD_REG 0x00
>>> +
>>> +/* SPI Interrupt registers */
>>> +# define SPI_IR_STAT_REG 0x02
>>> +# define SPI_IR_MASK_REG 0x04
>>> +
>>> +/* SPI Clock register */
>>> +# define SPI_CLK_REG 0x06
>>> +
>>> +/* SPI Fill register */
>>> +# define SPI_FILL_REG 0x07
>>> +
>>> +/* SPI Control register (8 bit) */
>>> +# define SPI_CTL_REG 0x40
>>> +# define SPI_CTL_BYTES_SHIFT 0
>>> +# define SPI_CTL_BYTES_MASK (0x3f << SPI_CTL_BYTES_SHIFT)
>>> +# define SPI_CTL_TYPE_SHIFT 6
>>> +# define SPI_CTL_TYPE_FD_RW (0 << SPI_CTL_TYPE_SHIFT)
>>> +# define SPI_CTL_TYPE_HD_W (1 << SPI_CTL_TYPE_SHIFT)
>>> +# define SPI_CTL_TYPE_HD_R (2 << SPI_CTL_TYPE_SHIFT)
>>> +
>>> +# define bcm63xx_spi_wctl(v,a) writeb_be(v, a);
>>> +
>>> +/* SPI TX Data registers */
>>> +# define SPI_TX_DATA_REG 0x41
>>> +# define SPI_TX_DATA_SIZE 0x3f
>>> +
>>> +/* SPI RX Data registers */
>>> +# define SPI_RX_DATA_REG 0x80
>>> +# define SPI_RX_DATA_SIZE 0x3f
>>> +
>>> +#elif defined(CONFIG_BCM6358_SPI)
>>> +
>>> +# define SPI_DT_ID "brcm,bcm6358-spi"
>>> +
>>> +/* SPI Control register (16 bit) */
>>> +# define SPI_CTL_REG 0x000
>>> +# define SPI_CTL_BYTES_SHIFT 0
>>> +# define SPI_CTL_BYTES_MASK (0x3ff << SPI_CTL_BYTES_SHIFT)
>>> +# define SPI_CTL_TYPE_SHIFT 14
>>> +# define SPI_CTL_TYPE_FD_RW (0 << SPI_CTL_TYPE_SHIFT)
>>> +# define SPI_CTL_TYPE_HD_W (1 << SPI_CTL_TYPE_SHIFT)
>>> +# define SPI_CTL_TYPE_HD_R (2 << SPI_CTL_TYPE_SHIFT)
>>> +
>>> +# define bcm63xx_spi_wctl(v,a) writew_be(v, a);
>>> +
>>> +/* SPI TX Data registers */
>>> +# define SPI_TX_DATA_REG 0x002
>>> +# define SPI_TX_DATA_SIZE 0x21e
>>> +
>>> +/* SPI RX Data registers */
>>> +# define SPI_RX_DATA_REG 0x400
>>> +# define SPI_RX_DATA_SIZE 0x220
>>> +
>>> +/* SPI Command register */
>>> +# define SPI_CMD_REG 0x700
>>> +
>>> +/* SPI Interrupt registers */
>>> +# define SPI_IR_STAT_REG 0x702
>>> +# define SPI_IR_MASK_REG 0x704
>>> +
>>> +/* SPI Clock register */
>>> +# define SPI_CLK_REG 0x706
>>> +
>>> +/* SPI Fill register */
>>> +# define SPI_FILL_REG 0x707
>>> +
>>> +#endif
>>> +
>>> +/* 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 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)
>>> +
>>> +/* 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)
>>> +
>>> +#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 }
>>> +};
>>> +
>>> +struct bcm63xx_spi_priv {
>>> + void __iomem *regs;
>>> + uint8_t num_cs;
>>> + size_t tx_bytes;
>>> +};
>>> +
>>> +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);
>>> +
>>> + if (mode & SPI_LSB_FIRST)
>>> + setbits_8(priv->regs + SPI_CLK_REG, SPI_CLK_BSWAP_MASK);
>>> + else
>>> + clrbits_8(priv->regs + SPI_CLK_REG, 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);
>>> + 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->regs + SPI_CLK_REG,
>>> + 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);
>>> + size_t data_bytes = bitlen / 8;
>>> +
>>> + if (flags & SPI_XFER_BEGIN) {
>>> + /* clear prepends */
>>> + priv->tx_bytes = 0;
>>> +
>>> + /* initialize hardware */
>>> + writeb_be(0, priv->regs + SPI_IR_MASK_REG);
>>> + }
>>> +
>>> + 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 > SPI_RX_DATA_SIZE) {
>>> + error("max rx bytes exceeded\n");
>>> + return -EMSGSIZE;
>>> + }
>>> + }
>>> +
>>> + if (dout) {
>>> + /* check tx size */
>>> + if (priv->tx_bytes + data_bytes > SPI_TX_DATA_SIZE) {
>>> + error("max tx bytes exceeded\n");
>>> + return -EMSGSIZE;
>>> + }
>>> +
>>> + /* copy tx data */
>>> + memcpy_toio(priv->regs + SPI_TX_DATA_REG + 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 = 0;
>>> + uint8_t irq;
>>> +
>>> + /* determine control config */
>>> + if (dout && !din) {
>>> + /* buffered write transfers */
>>> + val |= (priv->tx_bytes << SPI_CTL_BYTES_SHIFT);
>>> + val |= SPI_CTL_TYPE_HD_W;
>>> + priv->tx_bytes = 0;
>>> + } else {
>>> + if (dout && din && (flags & SPI_XFER_ONCE)) {
>>> + /* full duplex read/write */
>>> + val |= (data_bytes << SPI_CTL_BYTES_SHIFT);
>>> + val |= SPI_CTL_TYPE_FD_RW;
>>> + priv->tx_bytes = 0;
>>> + } else {
>>> + /* prepended write transfer */
>>> + val |= (data_bytes << SPI_CTL_BYTES_SHIFT);
>>> + val |= SPI_CTL_TYPE_HD_R;
>>> + if (priv->tx_bytes > SPI_CMD_PREPEND_BYTES) {
>>> + error("max prepend bytes exceeded\n");
>>> + return -EMSGSIZE;
>>> + }
>>> + }
>>> + }
>>> + bcm63xx_spi_wctl(val, priv->regs + SPI_CTL_REG);
>>> +
>>> + /* clear interrupts */
>>> + writeb_be(SPI_IR_CLEAR_MASK, priv->regs + SPI_IR_STAT_REG);
>>> +
>>> + /* 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;
>>> + writew_be(val, priv->regs + SPI_CMD_REG);
>>> +
>>> + /* enable interrupts */
>>> + writeb_be(SPI_IR_DONE_MASK, priv->regs + SPI_IR_MASK_REG);
>>> +
>>> + do {
>>> + /* read interupts */
>>> + irq = readb_be(priv->regs + SPI_IR_STAT_REG);
>>> +
>>> + /* transfer completed */
>>> + if (irq & SPI_IR_DONE_MASK)
>>> + break;
>>> + } while (1);
>>> +
>>> + /* copy rx data */
>>> + if (din)
>>> + memcpy_fromio(din, priv->regs + SPI_RX_DATA_REG,
>>> + data_bytes);
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static const struct dm_spi_ops bcm63xx_spi_ops = {
>>> + .cs_info = bcm63xx_spi_cs_info,
>>> + .set_mode = bcm63xx_spi_set_mode,
>>> + .set_speed = bcm63xx_spi_set_speed,
>>> + .xfer = bcm63xx_spi_xfer,
>>> +};
>>> +
>>> +static const struct udevice_id bcm63xx_spi_ids[] = {
>>> + { .compatible = SPI_DT_ID, },
>>> + { /* sentinel */ }
>>
>> Try to add .data with reg_space of respective controller, this will
>> eventually reduce to driver configs and make it CONFIG_BCM63XX and
>> reduce unneeded#ifdef.
> This implies adding considerable bloat to the driver...
> Is it imperative for the driver to be accepted?

Yes, as per as recent U-boot developement we're trying to reduce
defconfig code as possible and even this method can improve code
quality.

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