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net: rtl8169: Properly align buffers

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RX and TX descriptor rings should be aligned to 256 byte boundaries. Use
the DEFINE_ALIGN_BUFFER() macro to define the buffers so that they don't
have to be manually aligned later on. Also make sure that the buffers do
align to cache-line boundaries in case the cache-line is higher than the
256 byte alignment requirements of the NIC.

Also add a warning if the cache-line size is larger than the descriptor
size, because the driver may discard changes to descriptors made by the
hardware when requeuing RX buffers.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
This commit is contained in:
Thierry Reding 2014-12-09 22:25:25 -07:00 committed by Tom Warren
parent c94bbfdf51
commit dad3ba0f0b
1 changed files with 34 additions and 29 deletions
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63
drivers/net/rtl8169.c
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@ -277,23 +277,41 @@ struct RxDesc {
u32 buf_Haddr;
};
/* Define the TX Descriptor */
static u8 tx_ring[NUM_TX_DESC * sizeof(struct TxDesc) + 256];
/* __attribute__ ((aligned(256))); */
#define RTL8169_DESC_SIZE 16
/* Create a static buffer of size RX_BUF_SZ for each
TX Descriptor. All descriptors point to a
part of this buffer */
static unsigned char txb[NUM_TX_DESC * RX_BUF_SIZE];
#if ARCH_DMA_MINALIGN > 256
# define RTL8169_ALIGN ARCH_DMA_MINALIGN
#else
# define RTL8169_ALIGN 256
#endif
/*
* Warn if the cache-line size is larger than the descriptor size. In such
* cases the driver will likely fail because the CPU needs to flush the cache
* when requeuing RX buffers, therefore descriptors written by the hardware
* may be discarded.
*/
#if RTL8169_DESC_SIZE < ARCH_DMA_MINALIGN
#warning cache-line size is larger than descriptor size
#endif
/* Define the TX Descriptor */
DEFINE_ALIGN_BUFFER(struct TxDesc, tx_ring, NUM_TX_DESC, RTL8169_ALIGN);
/* Define the RX Descriptor */
static u8 rx_ring[NUM_RX_DESC * sizeof(struct TxDesc) + 256];
/* __attribute__ ((aligned(256))); */
DEFINE_ALIGN_BUFFER(struct RxDesc, rx_ring, NUM_RX_DESC, RTL8169_ALIGN);
/* Create a static buffer of size RX_BUF_SZ for each
RX Descriptor All descriptors point to a
part of this buffer */
static unsigned char rxb[NUM_RX_DESC * RX_BUF_SIZE];
/*
* Create a static buffer of size RX_BUF_SZ for each TX Descriptor. All
* descriptors point to a part of this buffer.
*/
DEFINE_ALIGN_BUFFER(u8, txb, NUM_TX_DESC * RX_BUF_SIZE, RTL8169_ALIGN);
/*
* Create a static buffer of size RX_BUF_SZ for each RX Descriptor. All
* descriptors point to a part of this buffer.
*/
DEFINE_ALIGN_BUFFER(u8, rxb, NUM_RX_DESC * RX_BUF_SIZE, RTL8169_ALIGN);
struct rtl8169_private {
void *mmio_addr; /* memory map physical address */
@ -301,8 +319,6 @@ struct rtl8169_private {
unsigned long cur_rx; /* Index into the Rx descriptor buffer of next Rx pkt. */
unsigned long cur_tx; /* Index into the Tx descriptor buffer of next Rx pkt. */
unsigned long dirty_tx;
unsigned char *TxDescArrays; /* Index of Tx Descriptor buffer */
unsigned char *RxDescArrays; /* Index of Rx Descriptor buffer */
struct TxDesc *TxDescArray; /* Index of 256-alignment Tx Descriptor buffer */
struct RxDesc *RxDescArray; /* Index of 256-alignment Rx Descriptor buffer */
unsigned char *RxBufferRings; /* Index of Rx Buffer */
@ -711,16 +727,6 @@ static int rtl_reset(struct eth_device *dev, bd_t *bis)
printf ("%s\n", __FUNCTION__);
#endif
tpc->TxDescArrays = tx_ring;
/* Tx Desscriptor needs 256 bytes alignment; */
tpc->TxDescArray = (struct TxDesc *) ((unsigned long)(tpc->TxDescArrays +
255) & ~255);
tpc->RxDescArrays = rx_ring;
/* Rx Desscriptor needs 256 bytes alignment; */
tpc->RxDescArray = (struct RxDesc *) ((unsigned long)(tpc->RxDescArrays +
255) & ~255);
rtl8169_init_ring(dev);
rtl8169_hw_start(dev);
/* Construct a perfect filter frame with the mac address as first match
@ -762,10 +768,6 @@ static void rtl_halt(struct eth_device *dev)
RTL_W32(RxMissed, 0);
tpc->TxDescArrays = NULL;
tpc->RxDescArrays = NULL;
tpc->TxDescArray = NULL;
tpc->RxDescArray = NULL;
for (i = 0; i < NUM_RX_DESC; i++) {
tpc->RxBufferRing[i] = NULL;
}
@ -910,6 +912,9 @@ static int rtl_init(struct eth_device *dev, bd_t *bis)
#endif
}
tpc->TxDescArray = tx_ring;
tpc->RxDescArray = rx_ring;
return 1;
}