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

[York Sun]

I shouldn't take this patch without Jagan's ack.

York

On 08/21/2017 05:03 AM, Suresh Gupta wrote:
> 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
> 
>