Hi all,
I've built current u-boot (v2019.07-rc4) with QSPI support for our i.MX7D Sabre
eval system. I am using mx7dsabresd_qspi_defconfig.
The resulting u-boot fails to read from QSPI, i.e. the data read is not the
same than that written before with a previous (v2018) version.
After some investigation I found that the 'is_controller_busy' function comes
back with -ETIMEDOUT during read operation, because the retry count of 5 is too
low.
To figure out how many retries are needed, I added some debug code as part of a
while(1) loop to the is_controller_busy function:
diff --git a/drivers/spi/fsl_qspi.c b/drivers/spi/fsl_qspi.c
index 1598c4f698..fa5b7a29f2 100644
--- a/drivers/spi/fsl_qspi.c
+++ b/drivers/spi/fsl_qspi.c
@@ -152,16 +152,20 @@ static inline int is_controller_busy(const struct
fsl_qspi_priv *priv)
u32 val;
const u32 mask = QSPI_SR_BUSY_MASK | QSPI_SR_AHB_ACC_MASK |
QSPI_SR_IP_ACC_MASK;
- unsigned int retry = 5;
+ unsigned int retry = 0;
do {
val = qspi_read32(priv->flags, &priv->regs->sr);
- if ((~val & mask) == mask)
+ if ((~val & mask) == mask) {
+ if (retry > 5)
+ printf("%s: timeout! retry = %d\n", __func__,
retry);
return 0;
+ }
udelay(1);
- } while (--retry);
+ retry++;
+ } while (1);
return -ETIMEDOUT;
}
On my MX7 eval system I found that a retry count between 73 and 147 is
necessary to make sure that the controller will be ready before the next
operation.
So from my point of view we have 2 options to fix this issue:
- increase retry from 5 to 200
- wait in an endless loop (while (1) ) and return only when the controller is
ready (which means that the board will hang if the controller doesn't come back
for some other reason.
What do you think?
Best regards,
Thomas Schäfer
SW Design Engineer
Kontron - An S&T Company
Heinrich-Barth-Straße 1-1a | 66115 Saarbrücken | Germany
thomas.schae...@kontron.com
http://www.kontron.com
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