[U-Boot] [PATCH] spi: fsl_qspi: Add controller busy check before new spi operation

[Suresh Gupta]

Hi York, 

Can I delegate this patch to you? Delegate to Jagan (SPI Maintainer) delays the acceptance process. 

Thanks 
SuresH

> -----Original Message-----
> From: Suresh Gupta [mailto:suresh.gupta at nxp.com]
> Sent: Monday, August 21, 2017 3:56 PM
> To: u-boot at lists.denx.de
> Cc: York Sun <york.sun at nxp.com>; jagan at openedev.com; Prabhakar Kushwaha
> <prabhakar.kushwaha at nxp.com>; Suresh Gupta <suresh.gupta at nxp.com>
> Subject: [PATCH] spi: fsl_qspi: Add controller busy check before new spi
> operation
> 
> It is recommended to check either controller is free to take new spi action. The
> IP_ACC and AHB_ACC bits indicates that the controller is busy in IP or AHB mode
> respectively.
> And the BUSY bit indicates that the controller is currently busy handling a
> transaction to an external flash device
> 
> Signed-off-by: Suresh Gupta <suresh.gupta at nxp.com>
> ---
>  drivers/spi/fsl_qspi.c | 26 ++++++++++++++++++++++++++  drivers/spi/fsl_qspi.h
> |  4 ++++
>  2 files changed, 30 insertions(+)
> 
> diff --git a/drivers/spi/fsl_qspi.c b/drivers/spi/fsl_qspi.c index 1dfa89a..69e9712
> 100644
> --- a/drivers/spi/fsl_qspi.c
> +++ b/drivers/spi/fsl_qspi.c
> @@ -165,6 +165,27 @@ static inline u32 qspi_endian_xchg(u32 data)  #endif  }
> 
> +static inline u32 qspi_controller_busy(struct fsl_qspi_priv *priv) {
> +	u32 sr;
> +	u32 retry = 5;
> +
> +	do {
> +		sr = qspi_read32(priv->flags, &priv->regs->sr);
> +		if ((sr & QSPI_SR_BUSY_MASK) ||
> +		    (sr & QSPI_SR_AHB_ACC_MASK) ||
> +		    (sr & QSPI_SR_IP_ACC_MASK)) {
> +			debug("The controller is busy, sr = 0x%x\n", sr);
> +			udelay(1);
> +		} else {
> +			break;
> +		}
> +	} while (--retry);
> +
> +	return (sr & QSPI_SR_BUSY_MASK) ||
> +		(sr & QSPI_SR_AHB_ACC_MASK) || (sr &
> QSPI_SR_IP_ACC_MASK); }
> +
>  static void qspi_set_lut(struct fsl_qspi_priv *priv)  {
>  	struct fsl_qspi_regs *regs = priv->regs; @@ -765,6 +786,11 @@ int
> qspi_xfer(struct fsl_qspi_priv *priv, unsigned int bitlen,
> 
>  	WATCHDOG_RESET();
> 
> +	if (qspi_controller_busy(priv)) {
> +		printf("ERROR : The controller is busy\n");
> +		return -EBUSY;
> +	}
> +
>  	if (dout) {
>  		if (flags & SPI_XFER_BEGIN) {
>  			priv->cur_seqid = *(u8 *)dout;
> diff --git a/drivers/spi/fsl_qspi.h b/drivers/spi/fsl_qspi.h index 6cb3610..e468eb2
> 100644
> --- a/drivers/spi/fsl_qspi.h
> +++ b/drivers/spi/fsl_qspi.h
> @@ -105,6 +105,10 @@ struct fsl_qspi_regs {
>  #define QSPI_RBCT_RXBRD_SHIFT		8
>  #define QSPI_RBCT_RXBRD_USEIPS		(1 <<
> QSPI_RBCT_RXBRD_SHIFT)
> 
> +#define QSPI_SR_AHB_ACC_SHIFT		2
> +#define QSPI_SR_AHB_ACC_MASK		(1 <<
> QSPI_SR_AHB_ACC_SHIFT)
> +#define QSPI_SR_IP_ACC_SHIFT		1
> +#define QSPI_SR_IP_ACC_MASK		(1 << QSPI_SR_IP_ACC_SHIFT)
>  #define QSPI_SR_BUSY_SHIFT		0
>  #define QSPI_SR_BUSY_MASK		(1 << QSPI_SR_BUSY_SHIFT)
> 
> --
> 1.9.3