[PATCH AUTOSEL for 4.9 25/52] tg3: Add workaround to restrict 5762 MRRS to 2048

Sasha Levin
2018-02-03T18:24:03Z

From: Siva Reddy Kallam <siva.kallam@broadcom.com>

[ Upstream commit 4419bb1cedcda0272e1dc410345c5a1d1da0e367 ]

One of AMD based server with 5762 hangs with jumbo frame traffic.
This AMD platform has southbridge limitation which is restricting MRRS
to 4000. As a work around, driver to restricts the MRRS to 2048 for
this particular 5762 NX1 card.

Signed-off-by: Siva Reddy Kallam <siva.kallam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
drivers/net/ethernet/broadcom/tg3.c | 10 ++++++++++
drivers/net/ethernet/broadcom/tg3.h | 4 ++++
2 files changed, 14 insertions(+)

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index bb22d325e965..3943c5c1281c 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -10049,6 +10049,16 @@ static int tg3_reset_hw(struct tg3 *tp, bool reset_phy)

tw32(GRC_MODE, tp->grc_mode | val);

+ /* On one of the AMD platform, MRRS is restricted to 4000 because of
+ * south bridge limitation. As a workaround, Driver is setting MRRS
+ * to 2048 instead of default 4096.
+ */
+ if (tp->pdev->subsystem_vendor == PCI_VENDOR_ID_DELL &&
+ tp->pdev->subsystem_device == TG3PCI_SUBDEVICE_ID_DELL_5762) {
+ val = tr32(TG3PCI_DEV_STATUS_CTRL) & ~MAX_READ_REQ_MASK;
+ tw32(TG3PCI_DEV_STATUS_CTRL, val | MAX_READ_REQ_SIZE_2048);
+ }
+
/* Setup the timer prescalar register. Clock is always 66Mhz. */
val = tr32(GRC_MISC_CFG);
val &= ~0xff;
diff --git a/drivers/net/ethernet/broadcom/tg3.h b/drivers/net/ethernet/broadcom/tg3.h
index 3b5e98ecba00..6e51b793615c 100644
--- a/drivers/net/ethernet/broadcom/tg3.h
+++ b/drivers/net/ethernet/broadcom/tg3.h
@@ -95,6 +95,7 @@
#define TG3PCI_SUBDEVICE_ID_DELL_JAGUAR 0x0106
#define TG3PCI_SUBDEVICE_ID_DELL_MERLOT 0x0109
#define TG3PCI_SUBDEVICE_ID_DELL_SLIM_MERLOT 0x010a
+#define TG3PCI_SUBDEVICE_ID_DELL_5762 0x07f0
#define TG3PCI_SUBVENDOR_ID_COMPAQ PCI_VENDOR_ID_COMPAQ
#define TG3PCI_SUBDEVICE_ID_COMPAQ_BANSHEE 0x007c
#define TG3PCI_SUBDEVICE_ID_COMPAQ_BANSHEE_2 0x009a
@@ -280,6 +281,9 @@
#define TG3PCI_STD_RING_PROD_IDX 0x00000098 /* 64-bit */
#define TG3PCI_RCV_RET_RING_CON_IDX 0x000000a0 /* 64-bit */
/* 0xa8 --> 0xb8 unused */
+#define TG3PCI_DEV_STATUS_CTRL 0x000000b4
+#define MAX_READ_REQ_SIZE_2048 0x00004000
+#define MAX_READ_REQ_MASK 0x00007000
#define TG3PCI_DUAL_MAC_CTRL 0x000000b8
#define DUAL_MAC_CTRL_CH_MASK 0x00000003
#define DUAL_MAC_CTRL_ID 0x00000004
--
2.11.0