Re: [PATCH v2 1/1 resend] spi: Using Trigger number to transmit/receive data

[Cao Minh Hiep <cm-hiep@jinso.co.jp>]

Hi Geert-san

Thanks for your comments.

I'm going to update a new version with your comments that you've pointed 
out for me,
I'll send you when I finish.

Best Regards,
Cao Minh Hiep.

On 2014年10月20日 18:33, Geert Uytterhoeven wrote:
> Hi Hiep-san,
>
> On Tue, Oct 14, 2014 at 2:57 AM, Cao Minh Hiep <cm-hiep@jinso.co.jp> wrote:
>> From: Hiep Cao Minh <cm-hiep@jinso.co.jp>
>>
>> In order to transmit and receive data when have 32 bytes of data that
>> ready has prepared on Transmit/Receive Buffer to transmit or receive.
>> Instead transmits/receives a byte data using Transmit/Receive Buffer
>> Data Triggering Number will improve the speed of transfer data.
>>
>> Signed-off-by: Hiep Cao Minh <cm-hiep@jinso.co.jp>
> Thanks for your patch!
>
>> --- a/drivers/spi/spi-rspi.c
>> +++ b/drivers/spi/spi-rspi.c
>> @@ -182,6 +182,13 @@
>>   #define SPBFCR_RXRST           0x40    /* Receive Buffer Data Reset */
>>   #define SPBFCR_TXTRG_MASK      0x30    /* Transmit Buffer Data Triggering Number */
>>   #define SPBFCR_RXTRG_MASK      0x07    /* Receive Buffer Data Triggering Number */
>> +/* QSPI on R-Car H2 */
> This applies not only to H2, but to all R-Car Gen2.
>
>> +#define SPBFCR_TXTRG_32B       0x00    /* 32Byte Transmit Buffer Triggering */
>> +#define SPBFCR_TXTRG_1B                0x30    /* 1Byte Transmit Buffer Triggering */
> The "32B" and "1B" don't match the documentation I have, which says for bits
> 5 and 4:
>
>     "When the number of bytes of data in the transmit buffer (SPTXB) is equal
>      to or less than the specified triggering number, the SPTEF flag is set to 1.
>
>      00: 31 bytes (1 byte available)
>      11: 0 byte (32 bytes available)"
>
> (of course this could be attributed to a bad translation from Japanese
> to English ;-)
>
> See also qspi_set_send_trigger() below...
>
>> +#define SPBFCR_RXTRG_1B                0x00    /* 32Byte Receive Buffer Triggering */
>> +#define SPBFCR_RXTRG_32B       0x07    /* 1Byte Receive Buffer Triggering */
> The comments seem to be swapped?
>
>> @@ -371,6 +378,52 @@ static int qspi_set_config_register(struct rspi_data *rspi, int access_size)
>>          return 0;
>>   }
>>
>> +static void qspi_update(const struct rspi_data *rspi, u8 mask, u8 val, u8 reg)
>> +{
>> +       u8 data;
>> +
>> +       data = rspi_read8(rspi, reg);
>> +       data &= ~mask;
>> +       data |= (val & mask);
>> +       rspi_write8(rspi, data, reg);
>> +}
>> +
>> +static int qspi_set_send_trigger(struct rspi_data *rspi, int len)
> unsigned int len
>
>> +{
>> +       int n;
> unsigned int n;
>
>> +
>> +       n = min(len, QSPI_BUFFER_SIZE);
>> +
>> +       if (len >= QSPI_BUFFER_SIZE) {
>> +               /* sets triggering number to 32 bytes */
>> +               qspi_update(rspi, SPBFCR_TXTRG_MASK,
>> +                            SPBFCR_TXTRG_32B, QSPI_SPBFCR);
>> +       } else {
>> +               /* sets triggering number to 1 byte */
>> +               qspi_update(rspi, SPBFCR_TXTRG_MASK,
>> +                            SPBFCR_TXTRG_1B, QSPI_SPBFCR);
>> +       }
> Haven't you swapped the two branches of the if statement?
> If len >= QSPI_BUFFER_SIZE, I'd expect you only want to be woken up
> if there are 32 available entries in the FIFO, i.e. when bits 5 and 4 are both
> one, which is the case for your definition of SPBFCR_TXTRG_1B.
>
>> +
>> +       return n;
>> +}
>> +
>> +static void qspi_set_receive_trigger(struct rspi_data *rspi, int len)
> unsigned int len
>
>> +{
>> +       int n;
> unsigned int n;
>
>> +
>> +       n = min(len, QSPI_BUFFER_SIZE);
>> +
>> +       if (len >= QSPI_BUFFER_SIZE) {
>> +               /* sets triggering number to 32 bytes */
>> +               qspi_update(rspi, SPBFCR_RXTRG_MASK,
>> +                            SPBFCR_RXTRG_32B, QSPI_SPBFCR);
>> +       } else {
>> +               /* sets triggering number to 1 byte */
>> +               qspi_update(rspi, SPBFCR_RXTRG_MASK,
>> +                            SPBFCR_RXTRG_1B, QSPI_SPBFCR);
>> +       }
>> +}
>> +
>>   #define set_config_register(spi, n) spi->ops->set_config_register(spi, n)
>>
>>   static void rspi_enable_irq(const struct rspi_data *rspi, u8 enable)
>> @@ -410,27 +463,40 @@ static inline int rspi_wait_for_rx_full(struct rspi_data *rspi)
>>          return rspi_wait_for_interrupt(rspi, SPSR_SPRF, SPCR_SPRIE);
>>   }
>>
>> -static int rspi_data_out(struct rspi_data *rspi, u8 data)
>> +static int rspi_wait_for_tx_empty_check(struct rspi_data *rspi)
>>   {
>>          int error = rspi_wait_for_tx_empty(rspi);
>>          if (error < 0) {
>>                  dev_err(&rspi->master->dev, "transmit timeout\n");
>>                  return error;
>>          }
> Perhaps the error check should just be moved inside rspi_wait_for_tx_empty(),
> so you don't have to introduce a new function?
>
>> -       rspi_write_data(rspi, data);
>> +
>>          return 0;
>>   }
>>
>> -static int rspi_data_in(struct rspi_data *rspi)
>> +static int rspi_wait_for_rx_full_check(struct rspi_data *rspi)
>>   {
>> -       int error;
>> -       u8 data;
>> -
>> -       error = rspi_wait_for_rx_full(rspi);
>> +       int error = rspi_wait_for_rx_full(rspi);
>>          if (error < 0) {
>>                  dev_err(&rspi->master->dev, "receive timeout\n");
>>                  return error;
> Perhaps the error check should just be moved inside rspi_wait_for_tx_full(),
> so you don't have to introduce a new function?
>
>>          }
>> +
>> +       return 0;
>> +}
>> +
>> +static int rspi_data_out(struct rspi_data *rspi, u8 data)
>> +{
>> +       rspi_wait_for_tx_empty_check(rspi);
> You forgot to check the return value of rspi_wait_for_tx_empty_check()?
>
>> +       rspi_write_data(rspi, data);
>> +       return 0;
>> +}
>> +
>> +static int rspi_data_in(struct rspi_data *rspi)
>> +{
>> +       u8 data;
>> +
>> +       rspi_wait_for_rx_full_check(rspi);
> You forgot to check the return value of rspi_wait_for_rx_full_check()?
>
>>          data = rspi_read_data(rspi);
>>          return data;
>>   }
>> @@ -614,19 +680,28 @@ static bool rspi_can_dma(struct spi_master *master, struct spi_device *spi,
>>          return __rspi_can_dma(rspi, xfer);
>>   }
>>
>> -static int rspi_common_transfer(struct rspi_data *rspi,
>> -                               struct spi_transfer *xfer)
>> +static int rspi_dma_check_then_transfer(struct rspi_data *rspi,
>> +                                        struct spi_transfer *xfer)
>>   {
>> -       int ret;
>> -
>>          if (rspi->master->can_dma && __rspi_can_dma(rspi, xfer)) {
>>                  /* rx_buf can be NULL on RSPI on SH in TX-only Mode */
>> -               ret = rspi_dma_transfer(rspi, &xfer->tx_sg,
>> +               int ret = rspi_dma_transfer(rspi, &xfer->tx_sg,
>>                                          xfer->rx_buf ? &xfer->rx_sg : NULL);
>>                  if (ret != -EAGAIN)
>>                          return ret;
> This returns zero on success...
>
>>          }
>>
>> +       return 0;
> ... but this also returns zero if DMA cannot be used?
> Shouldn't you return -EAGAIN here?
>
>> +}
>> +
>> +static int rspi_common_transfer(struct rspi_data *rspi,
>> +                               struct spi_transfer *xfer)
>> +{
>> +       int ret;
>> +
>> +       ret = rspi_dma_check_then_transfer(rspi, xfer);
>> +       if (ret < 0)
>> +               return ret;
> As rspi_dma_check_then_transfer() returns zero on success,
> it will continue below using PIO?
>
>>          ret = rspi_pio_transfer(rspi, xfer->tx_buf, xfer->rx_buf, xfer->len);
>>          if (ret < 0)
>>                  return ret;
>> @@ -666,12 +741,49 @@ static int rspi_rz_transfer_one(struct spi_master *master,
>>          return rspi_common_transfer(rspi, xfer);
>>   }
>>
>> +static int qspi_trigger_transfer_out_int(struct rspi_data *rspi, const u8 *tx,
>> +                                       u8 *rx, unsigned int len)
>> +{
>> +       int i, n, ret;
> unsigned int i, n;
>
>> +       while (len > 0) {
>> +               n = qspi_set_send_trigger(rspi, len);
>> +               qspi_set_receive_trigger(rspi, len);
>> +               if (n == QSPI_BUFFER_SIZE) {
>> +                       rspi_wait_for_tx_empty_check(rspi);
>> +                       for (i = 0; i < n; i++)
>> +                               rspi_write_data(rspi, *tx++);
>> +                       rspi_wait_for_rx_full_check(rspi);
>> +                       for (i = 0; i < n; i++)
>> +                               *rx++ = rspi_read_data(rspi);
>> +               } else {
>> +                       ret = rspi_pio_transfer(rspi, tx, rx, n);
>> +                       if (ret < 0)
>> +                               return ret;
>> +               }
>> +               len -= n;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>>   static int qspi_transfer_out_in(struct rspi_data *rspi,
>>                                  struct spi_transfer *xfer)
>>   {
>> +       int ret;
>> +
>>          qspi_receive_init(rspi);
>>
>> -       return rspi_common_transfer(rspi, xfer);
>> +       ret = rspi_dma_check_then_transfer(rspi, xfer);
>> +       if (ret < 0)
>> +               return ret;
> As rspi_dma_check_then_transfer() returns zero on success,
> it will continue below using PIO?
>
>> +
>> +       ret = qspi_trigger_transfer_out_int(rspi, xfer->tx_buf,
>> +                                           xfer->rx_buf, xfer->len);
>> +       if (ret < 0)
>> +               return ret;
>> +
>> +       return 0;
>>   }
> Gr{oetje,eeting}s,
>
>                          Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                  -- Linus Torvalds
> --
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