pm80xx: wait a minimum of 500ms before issuing commands to SPCv

The documentation for the 8070 and 8072 SPCv chip explicitly states that
a minimum of 500ms must elapse before issuing commands, otherwise the
SPCv may not process them and the firmware may get into an unrecoverable
state requiring a reboot.  While the Linux guys will probably think this
is 'racy', it is called out in the chip documentation and inserting this
delay makes power management function properly.

Signed-off-by: Benjamin Rood <brood@attotech.com>
Reviewed-by: Jack Wang <jinpu.wang@profitbricks.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/scsi/pm8001/pm8001_init.c b/drivers/scsi/pm8001/pm8001_init.c
index 7ce7ea3..d147c41 100644
--- a/drivers/scsi/pm8001/pm8001_init.c
+++ b/drivers/scsi/pm8001/pm8001_init.c
@@ -1243,6 +1243,19 @@ static int pm8001_pci_resume(struct pci_dev *pdev)
 		for (i = 1; i < pm8001_ha->number_of_intr; i++)
 			PM8001_CHIP_DISP->interrupt_enable(pm8001_ha, i);
 	}
+
+	/* Chip documentation for the 8070 and 8072 SPCv    */
+	/* states that a 500ms minimum delay is required    */
+	/* before issuing commands.  Otherwise, the firmare */
+	/* will enter an unrecoverable state.               */
+
+	if (pm8001_ha->chip_id == chip_8070 ||
+		pm8001_ha->chip_id == chip_8072) {
+		mdelay(500);
+	}
+
+	/* Spin up the PHYs */
+
 	pm8001_ha->flags = PM8001F_RUN_TIME;
 	for (i = 0; i < pm8001_ha->chip->n_phy; i++) {
 		pm8001_ha->phy[i].enable_completion = &completion;