diff options
Diffstat (limited to '8139cp-set-ring-address-after-enabling-C-mode.patch')
| -rw-r--r-- | 8139cp-set-ring-address-after-enabling-C-mode.patch | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/8139cp-set-ring-address-after-enabling-C-mode.patch b/8139cp-set-ring-address-after-enabling-C-mode.patch new file mode 100644 index 000000000..33bd340e9 --- /dev/null +++ b/8139cp-set-ring-address-after-enabling-C-mode.patch @@ -0,0 +1,100 @@ +From a9dbe40fc10cea2efe6e1ff9e03c62dd7579c5ba Mon Sep 17 00:00:00 2001 +From: David Woodhouse <dwmw2@infradead.org> +Date: Wed, 21 Nov 2012 10:27:19 +0000 +Subject: [PATCH] 8139cp: set ring address after enabling C+ mode + +This fixes (for me) a regression introduced by commit b01af457 ("8139cp: +set ring address before enabling receiver"). That commit configured the +descriptor ring addresses earlier in the initialisation sequence, in +order to avoid the possibility of triggering stray DMA before the +correct address had been set up. + +Unfortunately, it seems that the hardware will scribble garbage into the +TxRingAddr registers when we enable "plus mode" Tx in the CpCmd +register. Observed on a Traverse Geos router board. + +To deal with this, while not reintroducing the problem which led to the +original commit, we augment cp_start_hw() to write to the CpCmd register +*first*, then set the descriptor ring addresses, and then finally to +enable Rx and Tx in the original 8139 Cmd register. The datasheet +actually indicates that we should enable Tx/Rx in the Cmd register +*before* configuring the descriptor addresses, but that would appear to +re-introduce the problem that the offending commit b01af457 was trying +to solve. And this variant appears to work fine on real hardware. + +Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> +Cc: stable@kernel.org [3.5+] +Signed-off-by: David S. Miller <davem@davemloft.net> +--- + drivers/net/ethernet/realtek/8139cp.c | 40 +++++++++++++++++++++++---------- + 1 files changed, 28 insertions(+), 12 deletions(-) + +diff --git a/drivers/net/ethernet/realtek/8139cp.c b/drivers/net/ethernet/realtek/8139cp.c +index 1c81825..5166d94 100644 +--- a/drivers/net/ethernet/realtek/8139cp.c ++++ b/drivers/net/ethernet/realtek/8139cp.c +@@ -957,7 +957,35 @@ static void cp_reset_hw (struct cp_private *cp) + + static inline void cp_start_hw (struct cp_private *cp) + { ++ dma_addr_t ring_dma; ++ + cpw16(CpCmd, cp->cpcmd); ++ ++ /* ++ * These (at least TxRingAddr) need to be configured after the ++ * corresponding bits in CpCmd are enabled. Datasheet v1.6 §6.33 ++ * (C+ Command Register) recommends that these and more be configured ++ * *after* the [RT]xEnable bits in CpCmd are set. And on some hardware ++ * it's been observed that the TxRingAddr is actually reset to garbage ++ * when C+ mode Tx is enabled in CpCmd. ++ */ ++ cpw32_f(HiTxRingAddr, 0); ++ cpw32_f(HiTxRingAddr + 4, 0); ++ ++ ring_dma = cp->ring_dma; ++ cpw32_f(RxRingAddr, ring_dma & 0xffffffff); ++ cpw32_f(RxRingAddr + 4, (ring_dma >> 16) >> 16); ++ ++ ring_dma += sizeof(struct cp_desc) * CP_RX_RING_SIZE; ++ cpw32_f(TxRingAddr, ring_dma & 0xffffffff); ++ cpw32_f(TxRingAddr + 4, (ring_dma >> 16) >> 16); ++ ++ /* ++ * Strictly speaking, the datasheet says this should be enabled ++ * *before* setting the descriptor addresses. But what, then, would ++ * prevent it from doing DMA to random unconfigured addresses? ++ * This variant appears to work fine. ++ */ + cpw8(Cmd, RxOn | TxOn); + } + +@@ -969,7 +997,6 @@ static void cp_enable_irq(struct cp_private *cp) + static void cp_init_hw (struct cp_private *cp) + { + struct net_device *dev = cp->dev; +- dma_addr_t ring_dma; + + cp_reset_hw(cp); + +@@ -979,17 +1006,6 @@ static void cp_init_hw (struct cp_private *cp) + cpw32_f (MAC0 + 0, le32_to_cpu (*(__le32 *) (dev->dev_addr + 0))); + cpw32_f (MAC0 + 4, le32_to_cpu (*(__le32 *) (dev->dev_addr + 4))); + +- cpw32_f(HiTxRingAddr, 0); +- cpw32_f(HiTxRingAddr + 4, 0); +- +- ring_dma = cp->ring_dma; +- cpw32_f(RxRingAddr, ring_dma & 0xffffffff); +- cpw32_f(RxRingAddr + 4, (ring_dma >> 16) >> 16); +- +- ring_dma += sizeof(struct cp_desc) * CP_RX_RING_SIZE; +- cpw32_f(TxRingAddr, ring_dma & 0xffffffff); +- cpw32_f(TxRingAddr + 4, (ring_dma >> 16) >> 16); +- + cp_start_hw(cp); + cpw8(TxThresh, 0x06); /* XXX convert magic num to a constant */ + +-- +1.7.6.5 + |