[PATCH 0/2] stmmac: nfs reboot crash & jumbo frame handling fix

[PATCH 0/2] stmmac: nfs reboot crash & jumbo frame handling fix

[Deepak Sikri]

This patch set handles in the fixes for following bugs that were
observed during testing.
1. On Multiple reboot operations using nfs, system crash were observed
with inconsistency in status of dma descriptors.
2. There were data losses observed whenever the jumbo frames were used
for data transfers.

Deepak Sikri (2):
  stmmac: Fix for nfs hang on multiple reboot
  stmmac: Fix for higher mtu size handling

 drivers/net/ethernet/stmicro/stmmac/ring_mode.c   |    3 ++-
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c |    3 +++
 2 files changed, 5 insertions(+), 1 deletions(-)

-- 
1.7.2.2

[PATCH 1/2] stmmac: Fix for nfs hang on multiple reboot

[Deepak Sikri]

It was observed that during multiple reboots nfs hangs. The status of
receive descriptors shows that all the descriptors were in control of
CPU, and none were assigned to DMA.
Also the DMA status register confirmed that the Rx buffer is
unavailable.

This patch adds the fix for the same by adding the memory barriers to
ascertain that the all instructions before enabling the Rx or Tx DMA are
completed which involves the proper setting of the ownership bit in DMA
descriptors.

Signed-off-by: Deepak Sikri <deepak.sikri@st.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 51b3b68..ea3003e 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1212,6 +1212,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 		priv->hw->desc->prepare_tx_desc(desc, 0, len, csum_insertion);
 		wmb();
 		priv->hw->desc->set_tx_owner(desc);
+		wmb();
 	}
 
 	/* Interrupt on completition only for the latest segment */
@@ -1227,6 +1228,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	/* To avoid raise condition */
 	priv->hw->desc->set_tx_owner(first);
+	wmb();
 
 	priv->cur_tx++;
 
@@ -1290,6 +1292,7 @@ static inline void stmmac_rx_refill(struct stmmac_priv *priv)
 		}
 		wmb();
 		priv->hw->desc->set_rx_owner(p + entry);
+		wmb();
 	}
 }
 
-- 
1.7.2.2

[PATCH 2/2] stmmac: Fix for higher mtu size handling

[Deepak Sikri]

For the higher mtu sizes requiring the buffer size greater than 8192,
the buffers are sent or received using multiple dma descriptors/ same
descriptor with option of multi buffer handling.
It was observed during tests that the driver was missing on data
packets during the normal ping operations if the data buffers being used
catered to jumbo frame handling.

The memory barrriers are added in between preparation of dma descriptors
in the jumbo frame handling path to ensure all instructions before
enabling the dma are complete.

Signed-off-by: Deepak Sikri <deepak.sikri@st.com>
---
 drivers/net/ethernet/stmicro/stmmac/ring_mode.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
index fb8377d..4b785e1 100644
--- a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
+++ b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c
@@ -51,7 +51,7 @@ static unsigned int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
 		desc->des3 = desc->des2 + BUF_SIZE_4KiB;
 		priv->hw->desc->prepare_tx_desc(desc, 1, bmax,
 						csum);
-
+		wmb();
 		entry = (++priv->cur_tx) % txsize;
 		desc = priv->dma_tx + entry;
 
@@ -59,6 +59,7 @@ static unsigned int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
 					    len, DMA_TO_DEVICE);
 		desc->des3 = desc->des2 + BUF_SIZE_4KiB;
 		priv->hw->desc->prepare_tx_desc(desc, 0, len, csum);
+		wmb();
 		priv->hw->desc->set_tx_owner(desc);
 		priv->tx_skbuff[entry] = NULL;
 	} else {
-- 
1.7.2.2

Re: [PATCH 0/2] stmmac: nfs reboot crash & jumbo frame handling fix

[David Miller]

From: Deepak Sikri <deepak.sikri@st.com>
Date: Mon, 9 Jul 2012 12:44:44 +0530

> This patch set handles in the fixes for following bugs that were
> observed during testing.
> 1. On Multiple reboot operations using nfs, system crash were observed
> with inconsistency in status of dma descriptors.
> 2. There were data losses observed whenever the jumbo frames were used
> for data transfers.
> 
> Deepak Sikri (2):
>   stmmac: Fix for nfs hang on multiple reboot
>   stmmac: Fix for higher mtu size handling

All applied, thanks.