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fsi/fsi-master-gpio: Reduce dpoll clocks

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FSI_GPIO_DPOLL_CLOCKS is the number of clocks before sending
a DPOLL command after receiving a BUSY status. It should be
at least tSendDelay (16 clocks).

According to comments in the code, it needs to also be at least
21 clocks due to HW issues.

It's currently 100 clocks which impacts performances negatively
in some cases. Reduces it in half to 50 clocks which seems to
still be solid.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
This commit is contained in:
Benjamin Herrenschmidt 2018-05-08 11:46:18 +10:00
parent 97a4e5c95b
commit b632642e4c
1 changed files with 3 additions and 2 deletions
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5
drivers/fsi/fsi-master-gpio.c
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@ -29,7 +29,8 @@
#define FSI_GPIO_CMD_TERM 0x3f
#define FSI_GPIO_CMD_ABS_AR 0x4
#define FSI_GPIO_DPOLL_CLOCKS 100 /* < 21 will cause slave to hang */
#define FSI_GPIO_DPOLL_CLOCKS 50 /* < 21 will cause slave to hang */
/* Bus errors */
#define FSI_GPIO_ERR_BUSY 1 /* Slave stuck in busy state */
@ -43,7 +44,7 @@
#define FSI_GPIO_RESP_ACK 0
#define FSI_GPIO_RESP_ACKD 4
#define FSI_GPIO_MAX_BUSY 100
#define FSI_GPIO_MAX_BUSY 200
#define FSI_GPIO_MTOE_COUNT 1000
#define FSI_GPIO_DRAIN_BITS 20
#define FSI_GPIO_CRC_SIZE 4