Re: [PATCH] spi: fsl-espi: master->mem_ops is implemented in the controller

[Boris Brezillon]

On Fri, 17 Aug 2018 18:07:05 +0800
Chuanhua Han <chuanhua....@nxp.com> wrote:

> The length of the transmitted data needs to be adjusted due to the maximum 
> length limit for espi transmission messages
> 
> Signed-off-by: Chuanhua Han <chuanhua....@nxp.com>
> ---
>  drivers/spi/spi-fsl-espi.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c
> index 1d332e2..4724127 100644
> --- a/drivers/spi/spi-fsl-espi.c
> +++ b/drivers/spi/spi-fsl-espi.c
> @@ -22,6 +22,7 @@
>  #include <linux/spi/spi.h>
>  #include <linux/pm_runtime.h>
>  #include <sysdev/fsl_soc.h>
> +#include <linux/spi/spi-mem.h>
>  
>  /* eSPI Controller registers */
>  #define ESPI_SPMODE  0x00    /* eSPI mode register */
> @@ -659,6 +660,29 @@ static void fsl_espi_init_regs(struct device *dev, bool 
> initial)
>       fsl_espi_write_reg(espi, ESPI_SPMODE, SPMODE_INIT_VAL | SPMODE_ENABLE);
>  }
>  
> +static int fsl_espi_adjust_op_size(struct spi_mem *mem, struct spi_mem_op 
> *op)
> +{
> +     if (!mem || !op)
> +             return -EINVAL;
> +     op->data.nbytes = min3((unsigned long)op->data.nbytes,
> +                     spi_max_transfer_size(mem->spi),
> +                     spi_max_message_size(mem->spi) -
> +                     sizeof(op->cmd.opcode) -
> +                     op->addr.nbytes -
> +                     op->dummy.nbytes);

Oops! Looks like I was wrong in my initial review, this code is generic
and should be placed in spi_mem_adjust_op_size() if !ctlr->mem_ops
or !ctlr->mem_ops->exec_op:

int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
{
        struct spi_controller *ctlr = mem->spi->controller;

        if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
                return ctlr->mem_ops->adjust_op_size(mem, op);

        if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op)
                op->data.nbytes = min3((unsigned long)op->data.nbytes,
                                       spi_max_transfer_size(mem->spi),
                                       spi_max_message_size(mem->spi) -
                                       sizeof(op->cmd.opcode) -
                                       op->addr.nbytes -
                                       op->dummy.nbytes);

        return 0;
}

Also, you don't seem to check spi_max_message_size(mem->spi) value
before subtracting opcode, addr and dummy bytes.


> +     return 0;
> +}
> +
> +static int fsl_espi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
> +{
> +     return -ENOTSUPP;
> +}
> +
> +static const struct spi_controller_mem_ops fsl_espi_mem_ops = {
> +     .adjust_op_size = fsl_espi_adjust_op_size,
> +     .exec_op = fsl_espi_exec_op,
> +};
> +
>  static int fsl_espi_probe(struct device *dev, struct resource *mem,
>                         unsigned int irq, unsigned int num_cs)
>  {
> @@ -682,6 +706,7 @@ static int fsl_espi_probe(struct device *dev, struct 
> resource *mem,
>       master->auto_runtime_pm = true;
>       master->max_message_size = fsl_espi_max_message_size;
>       master->num_chipselect = num_cs;
> +     master->mem_ops = &fsl_espi_mem_ops;
>  
>       espi = spi_master_get_devdata(master);
>       spin_lock_init(&espi->lock);