diff options
author | Alexey Brodkin <Alexey.Brodkin@synopsys.com> | 2015-06-24 11:47:41 +0300 |
---|---|---|
committer | Ben Hutchings <ben@decadent.org.uk> | 2015-08-12 16:33:17 +0200 |
commit | 6ee65539ef4a1f14a972b2370985870f399b2555 (patch) | |
tree | afc0608d6c7713ca5bfca9f4372c5d11e0a41979 /drivers | |
parent | 40ce76dd060fd92f6f13398fd63c0df8dfd16d0a (diff) |
stmmac: troubleshoot unexpected bits in des0 & des1
commit f1590670ce069eefeb93916391a67643e6ad1630 upstream.
Current implementation of descriptor init procedure only takes
care about setting/clearing ownership flag in "des0"/"des1"
fields while it is perfectly possible to get unexpected bits
set because of the following factors:
[1] On driver probe underlying memory allocated with
dma_alloc_coherent() might not be zeroed and so
it will be filled with garbage.
[2] During driver operation some bits could be set by SD/MMC
controller (for example error flags etc).
And unexpected and/or randomly set flags in "des0"/"des1"
fields may lead to unpredictable behavior of GMAC DMA block.
This change addresses both items above with:
[1] Use of dma_zalloc_coherent() instead of simple
dma_alloc_coherent() to make sure allocated memory is
zeroed. That shouldn't affect performance because
this allocation only happens once on driver probe.
[2] Do explicit zeroing of both "des0" and "des1" fields
of all buffer descriptors during initialization of
DMA transfer.
And while at it fixed identation of dma_free_coherent()
counterpart as well.
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: arc-linux-dev@synopsys.com
Cc: linux-kernel@vger.kernel.org
Cc: David Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2:
- Adjust context, indentation
- Normal and extended descriptors are allocated in the same place here]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Acked-by: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/net/ethernet/stmicro/stmmac/descs.h | 2 | ||||
-rw-r--r-- | drivers/net/ethernet/stmicro/stmmac/enh_desc.c | 3 | ||||
-rw-r--r-- | drivers/net/ethernet/stmicro/stmmac/norm_desc.c | 3 | ||||
-rw-r--r-- | drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 18 |
4 files changed, 14 insertions, 12 deletions
diff --git a/drivers/net/ethernet/stmicro/stmmac/descs.h b/drivers/net/ethernet/stmicro/stmmac/descs.h index 9820ec842cc0..e93a0bf128be 100644 --- a/drivers/net/ethernet/stmicro/stmmac/descs.h +++ b/drivers/net/ethernet/stmicro/stmmac/descs.h @@ -153,6 +153,8 @@ struct dma_desc { u32 buffer2_size:13; u32 reserved4:3; } etx; /* -- enhanced -- */ + + u64 all_flags; } des01; unsigned int des2; unsigned int des3; diff --git a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c index d87976364ec5..73e647ba5517 100644 --- a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c +++ b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c @@ -232,6 +232,7 @@ static void enh_desc_init_rx_desc(struct dma_desc *p, unsigned int ring_size, { int i; for (i = 0; i < ring_size; i++) { + p->des01.all_flags = 0; p->des01.erx.own = 1; p->des01.erx.buffer1_size = BUF_SIZE_8KiB - 1; @@ -248,7 +249,7 @@ static void enh_desc_init_tx_desc(struct dma_desc *p, unsigned int ring_size) int i; for (i = 0; i < ring_size; i++) { - p->des01.etx.own = 0; + p->des01.all_flags = 0; ehn_desc_tx_set_on_ring_chain(p, (i == ring_size - 1)); p++; } diff --git a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c index fda5d2b31d3a..5bf9c3767154 100644 --- a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c +++ b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c @@ -126,6 +126,7 @@ static void ndesc_init_rx_desc(struct dma_desc *p, unsigned int ring_size, { int i; for (i = 0; i < ring_size; i++) { + p->des01.all_flags = 0; p->des01.rx.own = 1; p->des01.rx.buffer1_size = BUF_SIZE_2KiB - 1; @@ -141,7 +142,7 @@ static void ndesc_init_tx_desc(struct dma_desc *p, unsigned int ring_size) { int i; for (i = 0; i < ring_size; i++) { - p->des01.tx.own = 0; + p->des01.all_flags = 0; ndesc_tx_set_on_ring_chain(p, (i == (ring_size - 1))); p++; } diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index d4d2bc1de267..05852e3748e4 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -441,19 +441,17 @@ static void init_dma_desc_rings(struct net_device *dev) priv->rx_skbuff = kmalloc(sizeof(struct sk_buff *) * rxsize, GFP_KERNEL); priv->dma_rx = - (struct dma_desc *)dma_alloc_coherent(priv->device, - rxsize * - sizeof(struct dma_desc), - &priv->dma_rx_phy, - GFP_KERNEL); + (struct dma_desc *)dma_zalloc_coherent(priv->device, rxsize * + sizeof(struct dma_desc), + &priv->dma_rx_phy, + GFP_KERNEL); priv->tx_skbuff = kmalloc(sizeof(struct sk_buff *) * txsize, GFP_KERNEL); priv->dma_tx = - (struct dma_desc *)dma_alloc_coherent(priv->device, - txsize * - sizeof(struct dma_desc), - &priv->dma_tx_phy, - GFP_KERNEL); + (struct dma_desc *)dma_zalloc_coherent(priv->device, txsize * + sizeof(struct dma_desc), + &priv->dma_tx_phy, + GFP_KERNEL); if ((priv->dma_rx == NULL) || (priv->dma_tx == NULL)) { pr_err("%s:ERROR allocating the DMA Tx/Rx desc\n", __func__); |