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 <abrod...@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
--
1.8.1.2
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