From 77afdc56439c904b0a8ae167a0a899c1488b328a Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Thu, 23 Aug 2012 13:27:31 +0100 Subject: [PATCH] [realtek] Use explicit value for TCR.MXDMA Some RTL8169 cards (observed with an RTL8169SC) power up with TCR.MXDMA set to 16 bytes. While this does not prevent proper operation, it almost certainly degrades performance. Fix by explicitly setting TCR.MXDMA to "unlimited". Signed-off-by: Michael Brown --- src/drivers/net/realtek.c | 7 +++++++ src/drivers/net/realtek.h | 6 ++++++ 2 files changed, 13 insertions(+) diff --git a/src/drivers/net/realtek.c b/src/drivers/net/realtek.c index 2dded0a5..77df64e6 100644 --- a/src/drivers/net/realtek.c +++ b/src/drivers/net/realtek.c @@ -500,6 +500,7 @@ static void realtek_refill_rx ( struct realtek_nic *rtl ) { */ static int realtek_open ( struct net_device *netdev ) { struct realtek_nic *rtl = netdev->priv; + uint32_t tcr; uint32_t rcr; int rc; @@ -524,6 +525,12 @@ static int realtek_open ( struct net_device *netdev ) { */ writeb ( ( RTL_CR_TE | RTL_CR_RE ), rtl->regs + RTL_CR ); + /* Configure transmitter */ + tcr = readl ( rtl->regs + RTL_TCR ); + tcr &= ~RTL_TCR_MXDMA_MASK; + tcr |= RTL_TCR_MXDMA_DEFAULT; + writel ( tcr, rtl->regs + RTL_TCR ); + /* Configure receiver */ rcr = readl ( rtl->regs + RTL_RCR ); rcr &= ~( RTL_RCR_RXFTH_MASK | RTL_RCR_RBLEN_MASK | diff --git a/src/drivers/net/realtek.h b/src/drivers/net/realtek.h index 24ec09e7..2591e725 100644 --- a/src/drivers/net/realtek.h +++ b/src/drivers/net/realtek.h @@ -132,6 +132,12 @@ enum realtek_legacy_status { /** Interrupt Status Register (word) */ #define RTL_ISR 0x3e +/** Transmit (Tx) Configuration Register (dword) */ +#define RTL_TCR 0x40 +#define RTL_TCR_MXDMA(x) ( (x) << 8 ) /**< Max DMA burst size */ +#define RTL_TCR_MXDMA_MASK RTL_TCR_MXDMA ( 0x7 ) +#define RTL_TCR_MXDMA_DEFAULT RTL_TCR_MXDMA ( 0x7 /* Unlimited */ ) + /** Receive (Rx) Configuration Register (dword) */ #define RTL_RCR 0x44 #define RTL_RCR_RXFTH(x) ( (x) << 13 ) /**< Receive FIFO threshold */