From 4d95fbcd38406f6747aeb86560a15a95e4527cc4 Mon Sep 17 00:00:00 2001 From: Alexey Brodkin Date: Wed, 24 Jun 2015 11:47:41 +0300 Subject: 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 Cc: Giuseppe Cavallaro Cc: arc-linux-dev@synopsys.com Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org Cc: David Miller Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/stmicro/stmmac/descs.h | 2 ++ drivers/net/ethernet/stmicro/stmmac/enh_desc.c | 3 +- drivers/net/ethernet/stmicro/stmmac/norm_desc.c | 3 +- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 44 +++++++++++------------ 4 files changed, 28 insertions(+), 24 deletions(-) (limited to 'drivers/net/ethernet') diff --git a/drivers/net/ethernet/stmicro/stmmac/descs.h b/drivers/net/ethernet/stmicro/stmmac/descs.h index ad3996038018..799c2929c536 100644 --- a/drivers/net/ethernet/stmicro/stmmac/descs.h +++ b/drivers/net/ethernet/stmicro/stmmac/descs.h @@ -158,6 +158,8 @@ 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 1e2bcf5f89e1..7d944449f5ef 100644 --- a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c +++ b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c @@ -240,6 +240,7 @@ static int enh_desc_get_rx_status(void *data, struct stmmac_extra_stats *x, static void enh_desc_init_rx_desc(struct dma_desc *p, int disable_rx_ic, int mode, int end) { + p->des01.all_flags = 0; p->des01.erx.own = 1; p->des01.erx.buffer1_size = BUF_SIZE_8KiB - 1; @@ -254,7 +255,7 @@ static void enh_desc_init_rx_desc(struct dma_desc *p, int disable_rx_ic, static void enh_desc_init_tx_desc(struct dma_desc *p, int mode, int end) { - p->des01.etx.own = 0; + p->des01.all_flags = 0; if (mode == STMMAC_CHAIN_MODE) ehn_desc_tx_set_on_chain(p, end); else diff --git a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c index 35ad4f427ae2..48c3456445b2 100644 --- a/drivers/net/ethernet/stmicro/stmmac/norm_desc.c +++ b/drivers/net/ethernet/stmicro/stmmac/norm_desc.c @@ -123,6 +123,7 @@ static int ndesc_get_rx_status(void *data, struct stmmac_extra_stats *x, static void ndesc_init_rx_desc(struct dma_desc *p, int disable_rx_ic, int mode, int end) { + p->des01.all_flags = 0; p->des01.rx.own = 1; p->des01.rx.buffer1_size = BUF_SIZE_2KiB - 1; @@ -137,7 +138,7 @@ static void ndesc_init_rx_desc(struct dma_desc *p, int disable_rx_ic, int mode, static void ndesc_init_tx_desc(struct dma_desc *p, int mode, int end) { - p->des01.tx.own = 0; + p->des01.all_flags = 0; if (mode == STMMAC_CHAIN_MODE) ndesc_tx_set_on_chain(p, end); else diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 57ab4629ea2f..c274cdc5df1e 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -1192,41 +1192,41 @@ static int alloc_dma_desc_resources(struct stmmac_priv *priv) goto err_tx_skbuff; if (priv->extend_desc) { - priv->dma_erx = dma_alloc_coherent(priv->device, rxsize * - sizeof(struct - dma_extended_desc), - &priv->dma_rx_phy, - GFP_KERNEL); + priv->dma_erx = dma_zalloc_coherent(priv->device, rxsize * + sizeof(struct + dma_extended_desc), + &priv->dma_rx_phy, + GFP_KERNEL); if (!priv->dma_erx) goto err_dma; - priv->dma_etx = dma_alloc_coherent(priv->device, txsize * - sizeof(struct - dma_extended_desc), - &priv->dma_tx_phy, - GFP_KERNEL); + priv->dma_etx = dma_zalloc_coherent(priv->device, txsize * + sizeof(struct + dma_extended_desc), + &priv->dma_tx_phy, + GFP_KERNEL); if (!priv->dma_etx) { dma_free_coherent(priv->device, priv->dma_rx_size * - sizeof(struct dma_extended_desc), - priv->dma_erx, priv->dma_rx_phy); + sizeof(struct dma_extended_desc), + priv->dma_erx, priv->dma_rx_phy); goto err_dma; } } else { - priv->dma_rx = dma_alloc_coherent(priv->device, rxsize * - sizeof(struct dma_desc), - &priv->dma_rx_phy, - GFP_KERNEL); + priv->dma_rx = dma_zalloc_coherent(priv->device, rxsize * + sizeof(struct dma_desc), + &priv->dma_rx_phy, + GFP_KERNEL); if (!priv->dma_rx) goto err_dma; - priv->dma_tx = dma_alloc_coherent(priv->device, txsize * - sizeof(struct dma_desc), - &priv->dma_tx_phy, - GFP_KERNEL); + priv->dma_tx = dma_zalloc_coherent(priv->device, txsize * + sizeof(struct dma_desc), + &priv->dma_tx_phy, + GFP_KERNEL); if (!priv->dma_tx) { dma_free_coherent(priv->device, priv->dma_rx_size * - sizeof(struct dma_desc), - priv->dma_rx, priv->dma_rx_phy); + sizeof(struct dma_desc), + priv->dma_rx, priv->dma_rx_phy); goto err_dma; } } -- cgit v1.2.3