[U-Boot] [PATCH v3 1/8] spi: add support of SPI flash commands

[Jagan Teki <jagannadh.teki@gmail.com>]

On Tue, Jul 25, 2017 at 12:30 PM, Wenyou Yang <wenyou.yang@microchip.com> wrote:
> From: Cyrille Pitchen <cyrille.pitchen@atmel.com>
>
> This patch introduces 'struct spi_flash_command' and functions
> spi_is_flash_command_supported() / spi_exec_flash_command().
>

Answer for why this shouldn't be part of SPI area.

[snip]

drivers/spi and include/spi.h is Generic SPI area code - this can deal
all connected slave devices like EEPROM, SPI-NOR etc
drivers/mtd/spi and include/spi_flash.h is SPI-Flash or SPI-NOR code -
this can handle only SPI flashes.

>
> +bool dm_spi_is_flash_command_supported(struct udevice *dev,
> +                                      const struct spi_flash_command *cmd)
> +{
> +       struct udevice *bus = dev->parent;
> +       struct dm_spi_ops *ops = spi_get_ops(bus);
> +
> +       if (ops->is_flash_command_supported)
> +               return ops->is_flash_command_supported(dev, cmd);
> +
> +       return false;
> +}
> +
> +int dm_spi_exec_flash_command(struct udevice *dev,
> +                             const struct spi_flash_command *cmd)
> +{
> +       struct udevice *bus = dev->parent;
> +       struct dm_spi_ops *ops = spi_get_ops(bus);
> +
> +       if (ops->exec_flash_command)
> +               return ops->exec_flash_command(dev, cmd);
> +
> +       return -EINVAL;
> +}
> +
>  int spi_claim_bus(struct spi_slave *slave)
>  {
>         return dm_spi_claim_bus(slave->dev);
> @@ -107,6 +131,18 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
>         return dm_spi_xfer(slave->dev, bitlen, dout, din, flags);
>  }
>
> +bool spi_is_flash_command_supported(struct spi_slave *slave,
> +                                   const struct spi_flash_command *cmd)
> +{
> +       return dm_spi_is_flash_command_supported(slave->dev, cmd);
> +}
> +
> +int spi_exec_flash_command(struct spi_slave *slave,
> +                          const struct spi_flash_command *cmd)
> +{
> +       return dm_spi_exec_flash_command(slave->dev, cmd);
> +}

Handling spi-flash stuff in spi core is not proper way of dealing, and
I saw these functions are not-at-all needed for generic controller
drivers in drivers/spi except the Atmel QSPI driver (in v3,8/8).

> +
>  #if !CONFIG_IS_ENABLED(OF_PLATDATA)
>  static int spi_child_post_bind(struct udevice *dev)
>  {
> @@ -144,6 +180,10 @@ static int spi_post_probe(struct udevice *bus)
>                 ops->set_mode += gd->reloc_off;
>         if (ops->cs_info)
>                 ops->cs_info += gd->reloc_off;
> +       if (ops->is_flash_command_supported)
> +               ops->is_flash_command_supported += gd->reloc_off;
> +       if (ops->exec_flash_command)
> +               ops->exec_flash_command += gd->reloc_off;
>  #endif
>
>         return 0;
> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> index 7d81fbd7f8..e47acdc9e4 100644
> --- a/drivers/spi/spi.c
> +++ b/drivers/spi/spi.c
> @@ -5,6 +5,7 @@
>   */
>
>  #include <common.h>
> +#include <errno.h>
>  #include <fdtdec.h>
>  #include <malloc.h>
>  #include <spi.h>
> @@ -58,3 +59,15 @@ struct spi_slave *spi_base_setup_slave_fdt(const void *blob, int busnum,
>         return spi_setup_slave(busnum, cs, max_hz, mode);
>  }
>  #endif
> +
> +__weak bool spi_is_flash_command_supported(struct spi_slave *slave,
> +                                          const struct spi_flash_command *cmd)
> +{
> +       return false;
> +}
> +
> +__weak int spi_exec_flash_command(struct spi_slave *slave,
> +                                 const struct spi_flash_command *cmd)
> +{
> +       return -EINVAL;
> +}
> diff --git a/include/spi.h b/include/spi.h
> index 8c4b882c54..a090266b52 100644
> --- a/include/spi.h
> +++ b/include/spi.h
> @@ -10,6 +10,8 @@
>  #ifndef _SPI_H_
>  #define _SPI_H_
>
> +#include <linux/string.h> /* memset() */
> +
>  /* SPI mode flags */
>  #define SPI_CPHA       BIT(0)                  /* clock phase */
>  #define SPI_CPOL       BIT(1)                  /* clock polarity */
> @@ -64,6 +66,116 @@ struct dm_spi_slave_platdata {
>  #endif /* CONFIG_DM_SPI */
>
>  /**
> + * enum spi_flash_protocol - SPI flash command protocol
> + */
> +#define SPI_FPROTO_INST_SHIFT  16
> +#define SPI_FPROTO_INST_MASK   GENMASK(23, 16)
> +#define SPI_FPROTO_INST(nbits)                                 \
> +       ((((unsigned long)(nbits)) << SPI_FPROTO_INST_SHIFT) &  \
> +        SPI_FPROTO_INST_MASK)
> +
> +#define SPI_FPROTO_ADDR_SHIFT  8
> +#define SPI_FPROTO_ADDR_MASK   GENMASK(15, 8)
> +#define SPI_FPROTO_ADDR(nbits)                                 \
> +       ((((unsigned long)(nbits)) << SPI_FPROTO_ADDR_SHIFT) &  \
> +        SPI_FPROTO_ADDR_MASK)
> +
> +#define SPI_FPROTO_DATA_SHIFT  0
> +#define SPI_FPROTO_DATA_MASK   GENMASK(7, 0)
> +#define SPI_FPROTO_DATA(nbits)                                 \
> +       ((((unsigned long)(nbits)) << SPI_FPROTO_DATA_SHIFT) &  \
> +        SPI_FPROTO_DATA_MASK)
> +
> +#define SPI_FPROTO(inst_nbits, addr_nbits, data_nbits) \
> +       (SPI_FPROTO_INST(inst_nbits) |                  \
> +        SPI_FPROTO_ADDR(addr_nbits) |                  \
> +        SPI_FPROTO_DATA(data_nbits))
> +
> +enum spi_flash_protocol {
> +       SPI_FPROTO_1_1_1 = SPI_FPROTO(1, 1, 1),
> +       SPI_FPROTO_1_1_2 = SPI_FPROTO(1, 1, 2),
> +       SPI_FPROTO_1_1_4 = SPI_FPROTO(1, 1, 4),
> +       SPI_FPROTO_1_2_2 = SPI_FPROTO(1, 2, 2),
> +       SPI_FPROTO_1_4_4 = SPI_FPROTO(1, 4, 4),
> +       SPI_FPROTO_2_2_2 = SPI_FPROTO(2, 2, 2),
> +       SPI_FPROTO_4_4_4 = SPI_FPROTO(4, 4, 4),
> +};

these protocol also includes IO's like dual and quad and IO's which
are specific for SPI-NOR flash and not Generic SPI protocols.

> +
> +static inline
> +u8 spi_flash_protocol_get_inst_nbits(enum spi_flash_protocol proto)
> +{
> +       return ((unsigned long)(proto & SPI_FPROTO_INST_MASK)) >>
> +               SPI_FPROTO_INST_SHIFT;
> +}
> +
> +static inline
> +u8 spi_flash_protocol_get_addr_nbits(enum spi_flash_protocol proto)
> +{
> +       return ((unsigned long)(proto & SPI_FPROTO_ADDR_MASK)) >>
> +               SPI_FPROTO_ADDR_SHIFT;
> +}
> +
> +static inline
> +u8 spi_flash_protocol_get_data_nbits(enum spi_flash_protocol proto)
> +{
> +       return ((unsigned long)(proto & SPI_FPROTO_DATA_MASK)) >>
> +               SPI_FPROTO_DATA_SHIFT;
> +}
> +
> +/**
> + * struct spi_flash_command - SPI flash command structure
> + *
> + * @instr:             Opcode sent to the SPI slave during instr clock cycles.
> + * @mode:              Value sent to the SPI slave during mode clock cycles.
> + * @num_mode_cycles:   Number of mode clock cycles.
> + * @num_wait_states:   Number of wait-state clock cycles.
> + * @addr_len:          Number of bytes sent during address clock cycles:
> + *                     should be 0, 3, or 4.
> + * @addr:              Value sent to the SPI slave during address clock cycles.
> + * @data_len:          Number of bytes to be sent during data clock cycles.
> + * @tx_data:           Data sent to the SPI slave during data clock cycles.
> + * @rx_data:           Data read from the SPI slave during data clock cycles.
> + */
> +struct spi_flash_command {
> +       enum spi_flash_protocol proto;
> +       u8 flags;
> +#define SPI_FCMD_TYPE          GENMASK(2, 0)
> +#define SPI_FCMD_READ          (0x0U << 0)
> +#define SPI_FCMD_WRITE         (0x1U << 0)
> +#define SPI_FCMD_ERASE         (0x2U << 0)
> +#define SPI_FCMD_READ_REG      (0x3U << 0)
> +#define SPI_FCMD_WRITE_REG     (0x4U << 0)
> +
> +       u8 inst;
> +       u8 mode;
> +       u8 num_mode_cycles;
> +       u8 num_wait_states;
> +       u8 addr_len;
> +       u32 addr;
> +       size_t data_len;
> +       const void *tx_data;
> +       void *rx_data;
> +};

I saw from the other patches, this structure is initializing for each
I/O interface between SPI to driver/mtd like spi_transfer, if so it
shouldn't have flash attributes. Better to move flash contents to
spi_flash structure and do the respective operations.

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