It's important that buffer descriptors are aligned in accordance to GMAC data bus width (32/64/128-bit). It's safe to align to 128-bit (16-bytes) for every bus width type.

If buffer descriptor is improperly aligned GMAC discards lower bits of provided address and as a result reads from improper location that doesn't match expected fields.

Any other members of structure "dw_eth_dev" (and structure itself) don't need any specific alignment.

Moreover commit ef76025a99247cdb8f927a2c9f15400678dfb599 "net: Multiple updates/enhancements to designware.c" introduced another structure member "link_printed" right before buffer descriptors while "padding" member was left untouched. This together with alignment of structure itself to 8-byte boundary forces buffer descriptoprs always to be 4-byte aligned that causes driver complete disfunction if GMAC bus width is 64 or 128-bit.

Proposed change makes sure all buffer descriptors are 128-bit aligned.

Signed-off-by: Alexey Brodkin abrodkin@synopsys.com --- drivers/net/designware.c | 6 +----- drivers/net/designware.h | 7 +++---- 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/net/designware.c b/drivers/net/designware.c index f11cb0b..c8e3fc8 100644 --- a/drivers/net/designware.c +++ b/drivers/net/designware.c @@ -534,11 +534,7 @@ int designware_initialize(u32 id, ulong base_addr, u32 phy_addr, u32 interface) if (!dev) return -ENOMEM;

- /* - * Since the priv structure contains the descriptors which need a strict - * buswidth alignment, memalign is used to allocate memory - */ - priv = (struct dw_eth_dev *) memalign(16, sizeof(struct dw_eth_dev)); + priv = (struct dw_eth_dev *) malloc(sizeof(struct dw_eth_dev)); if (!priv) { free(dev); return -ENOMEM; diff --git a/drivers/net/designware.h b/drivers/net/designware.h index d668f8f..137acb0 100644 --- a/drivers/net/designware.h +++ b/drivers/net/designware.h @@ -128,7 +128,7 @@ struct dmamacdescr { u32 dmamac_cntl; void *dmamac_addr; struct dmamacdescr *dmamac_next; -}; +} __aligned(16);

/* * txrx_status definitions @@ -240,8 +240,7 @@ struct dw_eth_dev { u32 tx_currdescnum; u32 rx_currdescnum; u32 phy_configured; - int link_printed; - u32 padding; + u32 link_printed;

struct dmamacdescr tx_mac_descrtable[CONFIG_TX_DESCR_NUM]; struct dmamacdescr rx_mac_descrtable[CONFIG_RX_DESCR_NUM]; @@ -253,7 +252,7 @@ struct dw_eth_dev { struct eth_dma_regs *dma_regs_p;

struct eth_device *dev; -} __attribute__ ((aligned(8))); +};

/* Speed specific definitions */ #define SPEED_10M 1