On Mon, Jun 05, 2017 at 12:38:09PM +0900, Jiada Wang wrote:
> Previously i.MX SPI controller only works in Master mode.
> This patch adds support to i.MX51, i.MX53 and i.MX6 ECSPI
> controller to work also in Slave mode.
>
> Currently SPI Slave mode support patch has the following limitations:
> 1. The stale data in RXFIFO will be dropped when the Slave does any new
> transfer.
> 2. One transfer can be finished only after all transfer->len data been
> transferred to master device
> 3. Slave device only accepts transfer->len data. Any data longer than this
> from master device will be dropped. Any data shorter than this from
> master will cause SPI to stuck due to mentioned HW limitation 2.
> 4. Only PIO transfer is supported in Slave mode.
>
> Following HW limitation applies:
> 1. ECSPI has a HW issue when works in Slave mode, after 64
> words written to TXFIFO, even TXFIFO becomes empty,
> ECSPI_TXDATA keeps shift out the last word data,
> so we have to disable ECSPI when in slave mode after the
> transfer completes
> 2. Due to Freescale errata ERR003775 "eCSPI: Burst completion by Chip
> Select (SS) signal in Slave mode is not functional" burst size must
> be set exactly to the size of the transfer. This limit SPI transaction
> with maximum 2^12 bits. This errata affects i.MX53 and i.MX6 ECSPI
> controllers.
>
> Signed-off-by: Jiada Wang <jiada_wang@xxxxxxxxxx>
> ---
> drivers/spi/spi-imx.c | 228 +++++++++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 198 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
> index 5034f89..3db3809 100644
> --- a/drivers/spi/spi-imx.c
> +++ b/drivers/spi/spi-imx.c
> @@ -53,9 +53,13 @@
> /* generic defines to abstract from the different register layouts */
> #define MXC_INT_RR (1 << 0) /* Receive data ready interrupt */
> #define MXC_INT_TE (1 << 1) /* Transmit FIFO empty interrupt */
> +#define MXC_INT_RDR BIT(4) /* Receive date threshold interrupt */
>
> /* The maximum bytes that a sdma BD can transfer.*/
> #define MAX_SDMA_BD_BYTES (1 << 15)
> +/* The maximum bytes that IMX53_ECSPI can transfer in slave mode.*/
> +#define MX53_MAX_TRANSFER_BYTES 512
> +
> struct spi_imx_config {
> unsigned int speed_hz;
> unsigned int bpw;
> @@ -79,7 +83,9 @@ struct spi_imx_devtype_data {
> void (*trigger)(struct spi_imx_data *);
> int (*rx_available)(struct spi_imx_data *);
> void (*reset)(struct spi_imx_data *);
> + void (*disable)(struct spi_imx_data *);
> bool has_dmamode;
> + bool has_slavemode;
> unsigned int fifo_size;
> enum spi_imx_devtype devtype;
> };
> @@ -107,6 +113,11 @@ struct spi_imx_data {
> const void *tx_buf;
> unsigned int txfifo; /* number of words pushed in tx FIFO */
>
> + /* Slave mode */
> + bool slave_mode;
> + bool slave_aborted;
> + unsigned int slave_burst;
> +
> /* DMA */
> bool usedma;
> u32 wml;
> @@ -223,6 +234,9 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
> if (!transfer)
> return false;
>
> + if (spi_imx->slave_mode)
> + return false;
> +
> bpw = transfer->bits_per_word;
> if (!bpw)
> bpw = spi->bits_per_word;
> @@ -266,6 +280,7 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
> #define MX51_ECSPI_INT 0x10
> #define MX51_ECSPI_INT_TEEN (1 << 0)
> #define MX51_ECSPI_INT_RREN (1 << 3)
> +#define MX51_ECSPI_INT_RDREN (1 << 4)
>
> #define MX51_ECSPI_DMA 0x14
> #define MX51_ECSPI_DMA_TX_WML(wml) ((wml) & 0x3f)
> @@ -282,6 +297,46 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
> #define MX51_ECSPI_TESTREG 0x20
> #define MX51_ECSPI_TESTREG_LBC BIT(31)
>
> +static void mx53_ecspi_rx_slave(struct spi_imx_data *spi_imx)
> +{
> + u32 val = be32_to_cpu(readl(spi_imx->base + MXC_CSPIRXDATA));
> +
> + if (spi_imx->rx_buf) {
> + int n_bytes = spi_imx->slave_burst % sizeof(val);
> +
> + if (n_bytes) {
> + memcpy(spi_imx->rx_buf,
> + ((u8 *)&val) + sizeof(val) - n_bytes, n_bytes);
> + } else {
> + *((u32 *)spi_imx->rx_buf) = val;
> + n_bytes = sizeof(val);
> + }
> +
> + spi_imx->rx_buf += n_bytes;
> + spi_imx->slave_burst -= n_bytes;
> + }
> +}
You can do the same optimization you have done for mx53_ecspi_tx_slave()
for mx53_ecspi_rx_slave() aswell.
Otherwise the patch looks fine to me now.
Sascha
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