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arm: Kirkwood: Fix compiler optimization bug for kwgbe_send 

kwgbe_send/recv both have loops waiting for the hardware to set  a bit.
GCC 4.3.3 cleverly optimizes the send case to ... a while(1); loop. This
patch uses readl to force a read from device memory. Other volatile
accesses have also been replaced with readl/writel where appropriate
(as per suggestions on the U-boot mailing list).

Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>
This commit is contained in:
Simon Kagstrom 2009-07-08 13:03:18 +02:00 committed by Ben Warren
parent 3f6b18ffd9
commit 7b05f5e027
1 changed files with 19 additions and 12 deletions
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31
drivers/net/kirkwood_egiga.c
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@ -49,7 +49,7 @@ static int smi_reg_read(char *devname, u8 phy_adr, u8 reg_ofs, u16 * data)
struct kwgbe_device *dkwgbe = to_dkwgbe(dev);
struct kwgbe_registers *regs = dkwgbe->regs;
u32 smi_reg;
volatile u32 timeout;
u32 timeout;
/* Phyadr read request */
if (phy_adr == 0xEE && reg_ofs == 0xEE) {
@ -124,7 +124,7 @@ static int smi_reg_write(char *devname, u8 phy_adr, u8 reg_ofs, u16 data)
struct kwgbe_device *dkwgbe = to_dkwgbe(dev);
struct kwgbe_registers *regs = dkwgbe->regs;
u32 smi_reg;
volatile u32 timeout;
u32 timeout;
/* Phyadr write request*/
if (phy_adr == 0xEE && reg_ofs == 0xEE) {
@ -370,7 +370,7 @@ static void port_uc_addr_set(struct kwgbe_registers *regs, u8 * p_addr)
*/
static void kwgbe_init_rx_desc_ring(struct kwgbe_device *dkwgbe)
{
volatile struct kwgbe_rxdesc *p_rx_desc;
struct kwgbe_rxdesc *p_rx_desc;
int i;
/* initialize the Rx descriptors ring */
@ -487,6 +487,7 @@ static int kwgbe_send(struct eth_device *dev, volatile void *dataptr,
struct kwgbe_device *dkwgbe = to_dkwgbe(dev);
struct kwgbe_registers *regs = dkwgbe->regs;
struct kwgbe_txdesc *p_txdesc = dkwgbe->p_txdesc;
u32 cmd_sts;
if ((u32) dataptr & 0x07) {
printf("Err..(%s) xmit dataptr not 64bit aligned\n",
@ -507,21 +508,24 @@ static int kwgbe_send(struct eth_device *dev, volatile void *dataptr,
/*
* wait for packet xmit completion
*/
while (p_txdesc->cmd_sts & KWGBE_BUFFER_OWNED_BY_DMA) {
cmd_sts = readl(&p_txdesc->cmd_sts);
while (cmd_sts & KWGBE_BUFFER_OWNED_BY_DMA) {
/* return fail if error is detected */
if (p_txdesc->cmd_sts & (KWGBE_UR_ERROR | KWGBE_RL_ERROR)) {
if (cmd_sts & (KWGBE_UR_ERROR | KWGBE_RL_ERROR)) {
printf("Err..(%s) in xmit packet\n", __FUNCTION__);
return -1;
}
cmd_sts = readl(&p_txdesc->cmd_sts);
};
return 0;
}
static int kwgbe_recv(struct eth_device *dev)
{
volatile struct kwgbe_device *dkwgbe = to_dkwgbe(dev);
volatile struct kwgbe_rxdesc *p_rxdesc_curr = dkwgbe->p_rxdesc_curr;
volatile u32 timeout = 0;
struct kwgbe_device *dkwgbe = to_dkwgbe(dev);
struct kwgbe_rxdesc *p_rxdesc_curr = dkwgbe->p_rxdesc_curr;
u32 cmd_sts;
u32 timeout = 0;
/* wait untill rx packet available or timeout */
do {
@ -531,7 +535,7 @@ static int kwgbe_recv(struct eth_device *dev)
debug("%s time out...\n", __FUNCTION__);
return -1;
}
} while (p_rxdesc_curr->cmd_sts & KWGBE_BUFFER_OWNED_BY_DMA);
} while (readl(&p_rxdesc_curr->cmd_sts) & KWGBE_BUFFER_OWNED_BY_DMA);
if (p_rxdesc_curr->byte_cnt != 0) {
debug("%s: Received %d byte Packet @ 0x%x (cmd_sts= %08x)\n",
@ -545,14 +549,16 @@ static int kwgbe_recv(struct eth_device *dev)
* OR the error summary bit is on,
* the packets needs to be dropeed.
*/
if ((p_rxdesc_curr->cmd_sts &
cmd_sts = readl(&p_rxdesc_curr->cmd_sts);
if ((cmd_sts &
(KWGBE_RX_FIRST_DESC | KWGBE_RX_LAST_DESC))
!= (KWGBE_RX_FIRST_DESC | KWGBE_RX_LAST_DESC)) {
printf("Err..(%s) Dropping packet spread on"
" multiple descriptors\n", __FUNCTION__);
} else if (p_rxdesc_curr->cmd_sts & KWGBE_ERROR_SUMMARY) {
} else if (cmd_sts & KWGBE_ERROR_SUMMARY) {
printf("Err..(%s) Dropping packet with errors\n",
__FUNCTION__);
@ -574,7 +580,8 @@ static int kwgbe_recv(struct eth_device *dev)
p_rxdesc_curr->buf_size = PKTSIZE_ALIGN;
p_rxdesc_curr->byte_cnt = 0;
dkwgbe->p_rxdesc_curr = p_rxdesc_curr->nxtdesc_p;
writel((unsigned)p_rxdesc_curr->nxtdesc_p, &dkwgbe->p_rxdesc_curr);
return 0;
}