RE: [PATCH 12/15] spi/s3c64xx: Add support DMA engine API

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Jassi Brar Wrote:
> Sent: Tuesday, August 09, 2011 2:48 AM
> To: Boojin Kim
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-samsung-
> soc@xxxxxxxxxxxxxxx; Vinod Koul; Dan Williams; Kukjin Kim; Mark Brown;
> Grant Likely; Russell King
> Subject: Re: [PATCH 12/15] spi/s3c64xx: Add support DMA engine API
>
> On Wed, Jul 27, 2011 at 11:01 AM, Boojin Kim <boojin.kim@xxxxxxxxxxx>
> wrote:
> > This patch adds to support DMA generic API to transfer raw
> > SPI data. Basiclly the spi driver uses DMA generic API if
> > architecture supports it. Otherwise, uses Samsung specific
> > S3C-PL330 APIs.
> >
> > Signed-off-by: Boojin Kim <boojin.kim@xxxxxxxxxxx>
> > Acked-by: Grant Likely <grant.likely@xxxxxxxxxxxx>
> > Signed-off-by: Kukjin Kim <kgene.kim@xxxxxxxxxxx>
> > ---
> >  drivers/spi/spi_s3c64xx.c |  141 ++++++++++++++++++++++-------------
> ----------
> >  1 files changed, 69 insertions(+), 72 deletions(-)
> >
> > diff --git a/drivers/spi/spi_s3c64xx.c b/drivers/spi/spi_s3c64xx.c
> > index 8945e20..a4cf76a 100644
> > --- a/drivers/spi/spi_s3c64xx.c
> > +++ b/drivers/spi/spi_s3c64xx.c
> > @@ -172,6 +172,9 @@ struct s3c64xx_spi_driver_data {
> >        unsigned                        state;
> >        unsigned                        cur_mode, cur_bpw;
> >        unsigned                        cur_speed;
> > +       unsigned                        rx_ch;
> > +       unsigned                        tx_ch;
> > +       struct samsung_dma_ops          *ops;
> >  };
> >
> >  static struct s3c2410_dma_client s3c64xx_spi_dma_client = {
> > @@ -227,6 +230,38 @@ static void flush_fifo(struct
> s3c64xx_spi_driver_data *sdd)
> >        writel(val, regs + S3C64XX_SPI_CH_CFG);
> >  }
> >
> > +static void s3c64xx_spi_dma_rxcb(void *data)
> > +{
> > +       struct s3c64xx_spi_driver_data *sdd
> > +               = (struct s3c64xx_spi_driver_data *)data;
> void* doesn't need typecasting (same for all such occurances)
> IIRC someone already pointed it out?
I'm sorry for late response. (I was in vacation.)
This comment was reflected on 13/15 patch.

>
>
> > +       unsigned long flags;
> > +
> > +       spin_lock_irqsave(&sdd->lock, flags);
> > +
> > +       sdd->state &= ~RXBUSY;
> > +       /* If the other done */
> > +       if (!(sdd->state & TXBUSY))
> > +               complete(&sdd->xfer_completion);
> > +
> > +       spin_unlock_irqrestore(&sdd->lock, flags);
> > +}
> > +
> > +static void s3c64xx_spi_dma_txcb(void *data)
> > +{
> > +       struct s3c64xx_spi_driver_data *sdd
> > +               = (struct s3c64xx_spi_driver_data *)data;
> > +       unsigned long flags;
> > +
> > +       spin_lock_irqsave(&sdd->lock, flags);
> > +
> > +       sdd->state &= ~TXBUSY;
> > +       /* If the other done */
> > +       if (!(sdd->state & RXBUSY))
> > +               complete(&sdd->xfer_completion);
> > +
> > +       spin_unlock_irqrestore(&sdd->lock, flags);
> > +}
> > +
> >  static void enable_datapath(struct s3c64xx_spi_driver_data *sdd,
> >                                struct spi_device *spi,
> >                                struct spi_transfer *xfer, int dma_mode)
> > @@ -234,6 +269,7 @@ static void enable_datapath(struct
> s3c64xx_spi_driver_data *sdd,
> >        struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
> >        void __iomem *regs = sdd->regs;
> >        u32 modecfg, chcfg;
> > +       struct samsung_dma_prep_info info;
> >
> >        modecfg = readl(regs + S3C64XX_SPI_MODE_CFG);
> >        modecfg &= ~(S3C64XX_SPI_MODE_TXDMA_ON |
> S3C64XX_SPI_MODE_RXDMA_ON);
> > @@ -259,10 +295,14 @@ static void enable_datapath(struct
> s3c64xx_spi_driver_data *sdd,
> >                chcfg |= S3C64XX_SPI_CH_TXCH_ON;
> >                if (dma_mode) {
> >                        modecfg |= S3C64XX_SPI_MODE_TXDMA_ON;
> > -                       s3c2410_dma_config(sdd->tx_dmach, sdd->cur_bpw
> / 8);
> > -                       s3c2410_dma_enqueue(sdd->tx_dmach, (void *)sdd,
> > -                                               xfer->tx_dma, xfer->len);
> > -                       s3c2410_dma_ctrl(sdd->tx_dmach,
> S3C2410_DMAOP_START);
> > +                       info.cap = DMA_SLAVE;
> > +                       info.direction = DMA_TO_DEVICE;
> > +                       info.buf = xfer->tx_dma;
> > +                       info.len = xfer->len;
> > +                       info.fp = s3c64xx_spi_dma_txcb;
> > +                       info.fp_param = sdd;
> > +                       sdd->ops->prepare(sdd->tx_ch, &info);
> > +                       sdd->ops->trigger(sdd->tx_ch);
> >                } else {
> >                        switch (sdd->cur_bpw) {
> >                        case 32:
> > @@ -294,10 +334,14 @@ static void enable_datapath(struct
> s3c64xx_spi_driver_data *sdd,
> >                        writel(((xfer->len * 8 / sdd->cur_bpw) & 0xffff)
> >                                        | S3C64XX_SPI_PACKET_CNT_EN,
> >                                        regs + S3C64XX_SPI_PACKET_CNT);
> > -                       s3c2410_dma_config(sdd->rx_dmach, sdd->cur_bpw
> / 8);
> > -                       s3c2410_dma_enqueue(sdd->rx_dmach, (void *)sdd,
> > -                                               xfer->rx_dma, xfer->len);
> > -                       s3c2410_dma_ctrl(sdd->rx_dmach,
> S3C2410_DMAOP_START);
> > +                       info.cap = DMA_SLAVE;
> > +                       info.direction = DMA_FROM_DEVICE;
> > +                       info.buf = xfer->rx_dma;
> > +                       info.len = xfer->len;
> > +                       info.fp = s3c64xx_spi_dma_rxcb;
> > +                       info.fp_param = sdd;
> > +                       sdd->ops->prepare(sdd->rx_ch, &info);
> > +                       sdd->ops->trigger(sdd->rx_ch);
> >                }
> >        }
> >
> > @@ -483,46 +527,6 @@ static void s3c64xx_spi_config(struct
> s3c64xx_spi_driver_data *sdd)
> >        }
> >  }
> >
> > -static void s3c64xx_spi_dma_rxcb(struct s3c2410_dma_chan *chan,
> void *buf_id,
> > -                                int size, enum s3c2410_dma_buffresult
> res)
> > -{
> > -       struct s3c64xx_spi_driver_data *sdd = buf_id;
> > -       unsigned long flags;
> > -
> > -       spin_lock_irqsave(&sdd->lock, flags);
> > -
> > -       if (res == S3C2410_RES_OK)
> > -               sdd->state &= ~RXBUSY;
> > -       else
> > -               dev_err(&sdd->pdev->dev, "DmaAbrtRx-%d\n", size);
> > -
> > -       /* If the other done */
> > -       if (!(sdd->state & TXBUSY))
> > -               complete(&sdd->xfer_completion);
> > -
> > -       spin_unlock_irqrestore(&sdd->lock, flags);
> > -}
> > -
> > -static void s3c64xx_spi_dma_txcb(struct s3c2410_dma_chan *chan,
> void *buf_id,
> > -                                int size, enum s3c2410_dma_buffresult
> res)
> > -{
> > -       struct s3c64xx_spi_driver_data *sdd = buf_id;
> > -       unsigned long flags;
> > -
> > -       spin_lock_irqsave(&sdd->lock, flags);
> > -
> > -       if (res == S3C2410_RES_OK)
> > -               sdd->state &= ~TXBUSY;
> > -       else
> > -               dev_err(&sdd->pdev->dev, "DmaAbrtTx-%d \n", size);
> > -
> > -       /* If the other done */
> > -       if (!(sdd->state & RXBUSY))
> > -               complete(&sdd->xfer_completion);
> > -
> > -       spin_unlock_irqrestore(&sdd->lock, flags);
> > -}
> > -
> >  #define XFER_DMAADDR_INVALID DMA_BIT_MASK(32)
> >
> >  static int s3c64xx_spi_map_mssg(struct s3c64xx_spi_driver_data *sdd,
> > @@ -697,12 +701,10 @@ static void handle_msg(struct
> s3c64xx_spi_driver_data *sdd,
> >                        if (use_dma) {
> >                                if (xfer->tx_buf != NULL
> >                                                && (sdd->state & TXBUSY))
> > -                                       s3c2410_dma_ctrl(sdd->tx_dmach,
> > -
>                                                        S3C2410_DMAOP_FLUSH);
> > +                                       sdd->ops->stop(sdd->tx_ch);
> >                                if (xfer->rx_buf != NULL
> >                                                && (sdd->state & RXBUSY))
> > -                                       s3c2410_dma_ctrl(sdd->rx_dmach,
> > -
>                                                        S3C2410_DMAOP_FLUSH);
> > +                                       sdd->ops->stop(sdd->rx_ch);
> >                        }
> >
> >                        goto out;
> > @@ -742,24 +744,19 @@ out:
> >
> >  static int acquire_dma(struct s3c64xx_spi_driver_data *sdd)
> >  {
> > -       if (s3c2410_dma_request(sdd->rx_dmach,
> > -                                       &s3c64xx_spi_dma_client, NULL) <
> 0) {
> > -               dev_err(&sdd->pdev->dev, "cannot get RxDMA\n");
> > -               return 0;
> > -       }
> > -       s3c2410_dma_set_buffdone_fn(sdd->rx_dmach,
> s3c64xx_spi_dma_rxcb);
> > -       s3c2410_dma_devconfig(sdd->rx_dmach, S3C2410_DMASRC_HW,
> > -                                       sdd->sfr_start +
> S3C64XX_SPI_RX_DATA);
> > -
> > -       if (s3c2410_dma_request(sdd->tx_dmach,
> > -                                       &s3c64xx_spi_dma_client, NULL) <
> 0) {
> > -               dev_err(&sdd->pdev->dev, "cannot get TxDMA\n");
> > -               s3c2410_dma_free(sdd->rx_dmach,
> &s3c64xx_spi_dma_client);
> > -               return 0;
> > -       }
> > -       s3c2410_dma_set_buffdone_fn(sdd->tx_dmach,
> s3c64xx_spi_dma_txcb);
> > -       s3c2410_dma_devconfig(sdd->tx_dmach, S3C2410_DMASRC_MEM,
> > -                                       sdd->sfr_start +
> S3C64XX_SPI_TX_DATA);
> > +
> > +       struct samsung_dma_info info;
> > +       sdd->ops = samsung_dma_get_ops();
> > +
> > +       info.cap = DMA_SLAVE;
> > +       info.client = &s3c64xx_spi_dma_client;
> > +       info.direction = DMA_FROM_DEVICE;
> > +       info.fifo = sdd->sfr_start + S3C64XX_SPI_RX_DATA;
> > +       info.width = sdd->cur_bpw / 8;
> > +       sdd->rx_ch = sdd->ops->request(sdd->rx_dmach, &info);
> > +       info.direction = DMA_TO_DEVICE;
> > +       info.fifo = sdd->sfr_start + S3C64XX_SPI_TX_DATA;
> > +       sdd->tx_ch = sdd->ops->request(sdd->tx_dmach, &info);
> >
> >        return 1;
> >  }
> > @@ -800,8 +797,8 @@ static void s3c64xx_spi_work(struct work_struct
> *work)
> >        spin_unlock_irqrestore(&sdd->lock, flags);
> >
> >        /* Free DMA channels */
> > -       s3c2410_dma_free(sdd->tx_dmach, &s3c64xx_spi_dma_client);
> > -       s3c2410_dma_free(sdd->rx_dmach, &s3c64xx_spi_dma_client);
> > +       sdd->ops->release(sdd->rx_ch, &s3c64xx_spi_dma_client);
> > +       sdd->ops->release(sdd->tx_ch, &s3c64xx_spi_dma_client);
> >  }
>
> Btw, this spi driver is for S3C64xx(with pl080) and S5P(with pl330)
> series, both of which
> have DMAENGINE drivers. May be it could be directly switched to using
> those, rather than
> via Samsung's wrapper driver.
> Or am I overlooking something ?
Samsung is preparing to use PL080 with DMAENGINE. After this work is done, We 
will consider to using DMAENGINE API if required.



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