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authorRyan Harkin <ryan.harkin@linaro.org>2016-02-09 08:52:32 +0000
committerArd Biesheuvel <ard.biesheuvel@linaro.org>2016-02-10 17:56:39 +0100
commita4626006bbf86113453aeb7920895e66cdd04737 (patch)
tree755bea0bfc74590934ea761bd2f7aa5498a21a13 /EmbeddedPkg
parent7d0f92e8fd68e1f1242f36c203400be23954d563 (diff)
downloadedk2-platforms-a4626006bbf86113453aeb7920895e66cdd04737.tar.xz
EmbeddedPkg/Lan9118Dxe: use MemoryFence
When reviewing my LAN9118 driver PCD patch [1], Ard Biesheuvel noted that most calls to gBS->Stall() in this driver seem to be used to prevent timing issues between the device updating data and the host reading the values. And that replacing most of these calls with a MemoryFence() would be more robust. The only exceptions are the stalls that are enclosed inside retry loops: - in the AutoNegotiate() function. This stall is waiting for the link to negotiate, which may require stalling until it is ready. - in the Lan9118Initialize() function. These two stalls are waiting for devices and time out after a number of retries. - in the SoftReset() function. This stall is inside a loop where the comment states: "If time taken exceeds 100us, then there was an error condition" In these instances, I kept the stall, but also added a MemoryFence(). [1] http://article.gmane.org/gmane.comp.bios.edk2.devel/7389 Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ryan Harkin <ryan.harkin@linaro.org> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Diffstat (limited to 'EmbeddedPkg')
-rw-r--r--EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.c9
-rw-r--r--EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118DxeUtil.c40
2 files changed, 26 insertions, 23 deletions
diff --git a/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.c b/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.c
index 4de5204899..79bee3f47c 100644
--- a/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.c
+++ b/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118Dxe.c
@@ -307,8 +307,7 @@ SnpInitialize (
// Write the current configuration to the register
MmioWrite32 (LAN9118_PMT_CTRL, PmConf);
- gBS->Stall (LAN9118_STALL);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
// Configure GPIO and HW
Status = ConfigureHardware (HW_CONF_USE_LEDS, Snp);
@@ -431,7 +430,7 @@ SnpReset (
// Write the current configuration to the register
MmioWrite32 (LAN9118_PMT_CTRL, PmConf);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
// Reactivate the LEDs
Status = ConfigureHardware (HW_CONF_USE_LEDS, Snp);
@@ -446,7 +445,7 @@ SnpReset (
HwConf |= HW_CFG_TX_FIFO_SIZE(gTxBuffer); // assign size chosen in SnpInitialize
MmioWrite32 (LAN9118_HW_CFG, HwConf); // Write the conf
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
}
// Enable the receiver and transmitter and clear their contents
@@ -701,7 +700,7 @@ SnpReceiveFilters (
// Write the options to the MAC_CSR
//
IndirectMACWrite32 (INDIRECT_MAC_INDEX_CR, MacCSRValue);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
//
// If we have to retrieve something, start packet reception.
diff --git a/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118DxeUtil.c b/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118DxeUtil.c
index 9531b0ba2a..2ef1ecbb28 100644
--- a/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118DxeUtil.c
+++ b/EmbeddedPkg/Drivers/Lan9118Dxe/Lan9118DxeUtil.c
@@ -236,7 +236,7 @@ IndirectEEPROMRead32 (
// Write to Eeprom command register
MmioWrite32 (LAN9118_E2P_CMD, EepromCmd);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
// Wait until operation has completed
while (MmioRead32 (LAN9118_E2P_CMD) & E2P_EPC_BUSY);
@@ -284,7 +284,7 @@ IndirectEEPROMWrite32 (
// Write to Eeprom command register
MmioWrite32 (LAN9118_E2P_CMD, EepromCmd);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
// Wait until operation has completed
while (MmioRead32 (LAN9118_E2P_CMD) & E2P_EPC_BUSY);
@@ -362,13 +362,14 @@ Lan9118Initialize (
if (((MmioRead32 (LAN9118_PMT_CTRL) & MPTCTRL_PM_MODE_MASK) >> 12) != 0) {
DEBUG ((DEBUG_NET, "Waking from reduced power state.\n"));
MmioWrite32 (LAN9118_BYTE_TEST, 0xFFFFFFFF);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
}
// Check that device is active
Timeout = 20;
while ((MmioRead32 (LAN9118_PMT_CTRL) & MPTCTRL_READY) == 0 && --Timeout) {
gBS->Stall (LAN9118_STALL);
+ MemoryFence();
}
if (!Timeout) {
return EFI_TIMEOUT;
@@ -378,6 +379,7 @@ Lan9118Initialize (
Timeout = 20;
while ((MmioRead32 (LAN9118_E2P_CMD) & E2P_EPC_BUSY) && --Timeout){
gBS->Stall (LAN9118_STALL);
+ MemoryFence();
}
if (!Timeout) {
return EFI_TIMEOUT;
@@ -447,11 +449,12 @@ SoftReset (
// Write the configuration
MmioWrite32 (LAN9118_HW_CFG, HwConf);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
// Wait for reset to complete
while (MmioRead32 (LAN9118_HW_CFG) & HWCFG_SRST) {
+ MemoryFence();
gBS->Stall (LAN9118_STALL);
ResetTime += 1;
@@ -500,7 +503,7 @@ PhySoftReset (
// Wait for completion
while (MmioRead32 (LAN9118_PMT_CTRL) & MPTCTRL_PHY_RST) {
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
}
// PHY Basic Control Register reset
} else if (Flags & PHY_RESET_BCR) {
@@ -508,7 +511,7 @@ PhySoftReset (
// Wait for completion
while (IndirectPHYRead32 (PHY_INDEX_BASIC_CTRL) & PHYCR_RESET) {
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
}
}
@@ -542,7 +545,7 @@ ConfigureHardware (
// Write the configuration
MmioWrite32 (LAN9118_GPIO_CFG, GpioConf);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
}
return EFI_SUCCESS;
@@ -585,6 +588,7 @@ AutoNegotiate (
// Wait until it is up or until Time Out
TimeOut = 2000;
while ((IndirectPHYRead32 (PHY_INDEX_BASIC_STATUS) & PHYSTS_LINK_STS) == 0) {
+ MemoryFence();
gBS->Stall (LAN9118_STALL);
TimeOut--;
if (!TimeOut) {
@@ -671,7 +675,7 @@ StopTx (
TxCfg = MmioRead32 (LAN9118_TX_CFG);
TxCfg |= TXCFG_TXS_DUMP | TXCFG_TXD_DUMP;
MmioWrite32 (LAN9118_TX_CFG, TxCfg);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
}
// Check if already stopped
@@ -690,7 +694,7 @@ StopTx (
if (TxCfg & TXCFG_TX_ON) {
TxCfg |= TXCFG_STOP_TX;
MmioWrite32 (LAN9118_TX_CFG, TxCfg);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
// Wait for Tx to finish transmitting
while (MmioRead32 (LAN9118_TX_CFG) & TXCFG_STOP_TX);
@@ -725,7 +729,7 @@ StopRx (
RxCfg = MmioRead32 (LAN9118_RX_CFG);
RxCfg |= RXCFG_RX_DUMP;
MmioWrite32 (LAN9118_RX_CFG, RxCfg);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
while (MmioRead32 (LAN9118_RX_CFG) & RXCFG_RX_DUMP);
}
@@ -751,28 +755,28 @@ StartTx (
TxCfg = MmioRead32 (LAN9118_TX_CFG);
TxCfg |= TXCFG_TXS_DUMP | TXCFG_TXD_DUMP;
MmioWrite32 (LAN9118_TX_CFG, TxCfg);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
}
// Check if tx was started from MAC and enable if not
if (Flags & START_TX_MAC) {
MacCsr = IndirectMACRead32 (INDIRECT_MAC_INDEX_CR);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
if ((MacCsr & MACCR_TX_EN) == 0) {
MacCsr |= MACCR_TX_EN;
IndirectMACWrite32 (INDIRECT_MAC_INDEX_CR, MacCsr);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
}
}
// Check if tx was started from TX_CFG and enable if not
if (Flags & START_TX_CFG) {
TxCfg = MmioRead32 (LAN9118_TX_CFG);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
if ((TxCfg & TXCFG_TX_ON) == 0) {
TxCfg |= TXCFG_TX_ON;
MmioWrite32 (LAN9118_TX_CFG, TxCfg);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
}
}
@@ -802,14 +806,14 @@ StartRx (
RxCfg = MmioRead32 (LAN9118_RX_CFG);
RxCfg |= RXCFG_RX_DUMP;
MmioWrite32 (LAN9118_RX_CFG, RxCfg);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
while (MmioRead32 (LAN9118_RX_CFG) & RXCFG_RX_DUMP);
}
MacCsr |= MACCR_RX_EN;
IndirectMACWrite32 (INDIRECT_MAC_INDEX_CR, MacCsr);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
}
return EFI_SUCCESS;
@@ -999,7 +1003,7 @@ ChangeFifoAllocation (
HwConf &= ~(0xF0000);
HwConf |= ((TxFifoOption & 0xF) << 16);
MmioWrite32 (LAN9118_HW_CFG, HwConf);
- gBS->Stall (LAN9118_STALL);
+ MemoryFence();
return EFI_SUCCESS;
}