[hermon] Minimise reset time

Check for reset completion by waiting for the device to respond to PCI
configuration cycles, as documented in the Programmer's Reference
Manual.  On the original ConnectX HCA, this reduces the time spent on
reset from 1000ms down to 1ms.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 31 insertions, 6 deletions

diff --git a/src/drivers/infiniband/hermon.c b/src/drivers/infiniband/hermon.c
index 35326ac6e..d13a14678 100644
--- a/src/drivers/infiniband/hermon.c
+++ b/src/drivers/infiniband/hermon.c
@@ -2792,22 +2792,45 @@ static void hermon_unmap_icm ( struct hermon *hermon ) {
  * Reset device
  *
  * @v hermon		Hermon device
+ * @ret rc		Return status code
  */
-static void hermon_reset ( struct hermon *hermon ) {
+static int hermon_reset ( struct hermon *hermon ) {
 	struct pci_device *pci = hermon->pci;
 	struct pci_config_backup backup;
 	static const uint8_t backup_exclude[] =
 		PCI_CONFIG_BACKUP_EXCLUDE ( 0x58, 0x5c );
+	uint16_t vendor;
+	unsigned int i;
+
+	/* Reset command interface toggle */
+	hermon->toggle = 0;
 
 	/* Perform device reset and preserve PCI configuration */
 	pci_backup ( pci, &backup, backup_exclude );
 	writel ( HERMON_RESET_MAGIC,
 		 ( hermon->config + HERMON_RESET_OFFSET ) );
-	mdelay ( HERMON_RESET_WAIT_TIME_MS );
-	pci_restore ( pci, &backup, backup_exclude );
 
-	/* Reset command interface toggle */
-	hermon->toggle = 0;
+	/* Wait until device starts responding to configuration cycles */
+	for ( i = 0 ; i < HERMON_RESET_MAX_WAIT_MS ; i++ ) {
+
+		/* Read PCI vendor ID */
+		pci_read_config_word ( pci, PCI_VENDOR_ID, &vendor );
+		if ( vendor == pci->vendor ) {
+
+			/* Restore PCI configuration */
+			pci_restore ( pci, &backup, backup_exclude );
+
+			DBGC ( hermon, "Hermon %p reset after %dms\n",
+			       hermon, i );
+			return 0;
+		}
+
+		/* Delay */
+		mdelay ( 1 );
+	}
+
+	DBGC ( hermon, "Hermon %p timed out waiting for reset\n", hermon );
+	return -ETIMEDOUT;
 }
 
 /**
@@ -3967,7 +3990,8 @@ static int hermon_probe ( struct pci_device *pci ) {
 				    HERMON_UAR_NON_EQ_PAGE * HERMON_PAGE_SIZE );
 
 	/* Reset device */
-	hermon_reset ( hermon );
+	if ( ( rc = hermon_reset ( hermon ) ) != 0 )
+		goto err_reset;
 
 	/* Start firmware */
 	if ( ( rc = hermon_start_firmware ( hermon ) ) != 0 )
@@ -4060,6 +4084,7 @@ static int hermon_probe ( struct pci_device *pci ) {
  err_get_cap:
 	hermon_stop_firmware ( hermon );
  err_start_firmware:
+ err_reset:
 	iounmap ( hermon->uar );
 	iounmap ( hermon->config );
 	hermon_free ( hermon );