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Revert "sfc: Use write-combining to reduce TX latency" and follow-ups

Browse source 
This reverts commits 65f0b417de,
d88d6b05fe,
fcfa060468,
747df2258b and
867955f568.

Depending on the processor model, write-combining may result in
reordering that the NIC will not tolerate.  This typically results
in a DMA error event and reset by the driver, logged as:

sfc 0000:0e:00.0: eth2: TX DMA Q reports TX_EV_PKT_ERR.
sfc 0000:0e:00.0: eth2: resetting (ALL)

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ben Hutchings 2011-09-01 12:09:29 +00:00 committed by David S. Miller
parent 883cb07583
commit 86c432ca5d
7 changed files with 27 additions and 88 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

18
drivers/net/sfc/efx.c
View file

@ -1050,7 +1050,6 @@ static int efx_init_io(struct efx_nic *efx)
{
struct pci_dev *pci_dev = efx->pci_dev;
dma_addr_t dma_mask = efx->type->max_dma_mask;
bool use_wc;
int rc;
netif_dbg(efx, probe, efx->net_dev, "initialising I/O\n");
@ -1101,21 +1100,8 @@ static int efx_init_io(struct efx_nic *efx)
rc = -EIO;
goto fail3;
}
/* bug22643: If SR-IOV is enabled then tx push over a write combined
* mapping is unsafe. We need to disable write combining in this case.
* MSI is unsupported when SR-IOV is enabled, and the firmware will
* have removed the MSI capability. So write combining is safe if
* there is an MSI capability.
*/
use_wc = (!EFX_WORKAROUND_22643(efx) ||
pci_find_capability(pci_dev, PCI_CAP_ID_MSI));
if (use_wc)
efx->membase = ioremap_wc(efx->membase_phys,
efx->type->mem_map_size);
else
efx->membase = ioremap_nocache(efx->membase_phys,
efx->type->mem_map_size);
efx->membase = ioremap_nocache(efx->membase_phys,
efx->type->mem_map_size);
if (!efx->membase) {
netif_err(efx, probe, efx->net_dev,
"could not map memory BAR at %llx+%x\n",

15
drivers/net/sfc/io.h
View file

@ -48,9 +48,9 @@
* replacing the low 96 bits with zero does not affect functionality.
* - If the host writes to the last dword address of such a register
* (i.e. the high 32 bits) the underlying register will always be
* written. If the collector and the current write together do not
* provide values for all 128 bits of the register, the low 96 bits
* will be written as zero.
* written. If the collector does not hold values for the low 96
* bits of the register, they will be written as zero. Writing to
* the last qword does not have this effect and must not be done.
* - If the host writes to the address of any other part of such a
* register while the collector already holds values for some other
* register, the write is discarded and the collector maintains its
@ -103,7 +103,6 @@ static inline void efx_writeo(struct efx_nic *efx, efx_oword_t *value,
_efx_writed(efx, value->u32[2], reg + 8);
_efx_writed(efx, value->u32[3], reg + 12);
#endif
wmb();
mmiowb();
spin_unlock_irqrestore(&efx->biu_lock, flags);
}
@ -126,7 +125,6 @@ static inline void efx_sram_writeq(struct efx_nic *efx, void __iomem *membase,
__raw_writel((__force u32)value->u32[0], membase + addr);
__raw_writel((__force u32)value->u32[1], membase + addr + 4);
#endif
wmb();
mmiowb();
spin_unlock_irqrestore(&efx->biu_lock, flags);
}
@ -141,7 +139,6 @@ static inline void efx_writed(struct efx_nic *efx, efx_dword_t *value,
/* No lock required */
_efx_writed(efx, value->u32[0], reg);
wmb();
}
/* Read a 128-bit CSR, locking as appropriate. */
@ -152,7 +149,6 @@ static inline void efx_reado(struct efx_nic *efx, efx_oword_t *value,
spin_lock_irqsave(&efx->biu_lock, flags);
value->u32[0] = _efx_readd(efx, reg + 0);
rmb();
value->u32[1] = _efx_readd(efx, reg + 4);
value->u32[2] = _efx_readd(efx, reg + 8);
value->u32[3] = _efx_readd(efx, reg + 12);
@ -175,7 +171,6 @@ static inline void efx_sram_readq(struct efx_nic *efx, void __iomem *membase,
value->u64[0] = (__force __le64)__raw_readq(membase + addr);
#else
value->u32[0] = (__force __le32)__raw_readl(membase + addr);
rmb();
value->u32[1] = (__force __le32)__raw_readl(membase + addr + 4);
#endif
spin_unlock_irqrestore(&efx->biu_lock, flags);
@ -242,14 +237,12 @@ static inline void _efx_writeo_page(struct efx_nic *efx, efx_oword_t *value,
#ifdef EFX_USE_QWORD_IO
_efx_writeq(efx, value->u64[0], reg + 0);
_efx_writeq(efx, value->u64[1], reg + 8);
#else
_efx_writed(efx, value->u32[0], reg + 0);
_efx_writed(efx, value->u32[1], reg + 4);
#endif
_efx_writed(efx, value->u32[2], reg + 8);
_efx_writed(efx, value->u32[3], reg + 12);
#endif
wmb();
}
#define efx_writeo_page(efx, value, reg, page) \
_efx_writeo_page(efx, value, \

46
drivers/net/sfc/mcdi.c
View file

@ -50,20 +50,6 @@ static inline struct efx_mcdi_iface *efx_mcdi(struct efx_nic *efx)
return &nic_data->mcdi;
}
static inline void
efx_mcdi_readd(struct efx_nic *efx, efx_dword_t *value, unsigned reg)
{
struct siena_nic_data *nic_data = efx->nic_data;
value->u32[0] = (__force __le32)__raw_readl(nic_data->mcdi_smem + reg);
}
static inline void
efx_mcdi_writed(struct efx_nic *efx, const efx_dword_t *value, unsigned reg)
{
struct siena_nic_data *nic_data = efx->nic_data;
__raw_writel((__force u32)value->u32[0], nic_data->mcdi_smem + reg);
}
void efx_mcdi_init(struct efx_nic *efx)
{
struct efx_mcdi_iface *mcdi;
@ -84,8 +70,8 @@ static void efx_mcdi_copyin(struct efx_nic *efx, unsigned cmd,
const u8 *inbuf, size_t inlen)
{
struct efx_mcdi_iface *mcdi = efx_mcdi(efx);
unsigned pdu = MCDI_PDU(efx);
unsigned doorbell = MCDI_DOORBELL(efx);
unsigned pdu = FR_CZ_MC_TREG_SMEM + MCDI_PDU(efx);
unsigned doorbell = FR_CZ_MC_TREG_SMEM + MCDI_DOORBELL(efx);
unsigned int i;
efx_dword_t hdr;
u32 xflags, seqno;
@ -106,28 +92,29 @@ static void efx_mcdi_copyin(struct efx_nic *efx, unsigned cmd,
MCDI_HEADER_SEQ, seqno,
MCDI_HEADER_XFLAGS, xflags);
efx_mcdi_writed(efx, &hdr, pdu);
efx_writed(efx, &hdr, pdu);
for (i = 0; i < inlen; i += 4)
efx_mcdi_writed(efx, (const efx_dword_t *)(inbuf + i),
pdu + 4 + i);
_efx_writed(efx, *((__le32 *)(inbuf + i)), pdu + 4 + i);
/* Ensure the payload is written out before the header */
wmb();
/* ring the doorbell with a distinctive value */
EFX_POPULATE_DWORD_1(hdr, EFX_DWORD_0, 0x45789abc);
efx_mcdi_writed(efx, &hdr, doorbell);
_efx_writed(efx, (__force __le32) 0x45789abc, doorbell);
}
static void efx_mcdi_copyout(struct efx_nic *efx, u8 *outbuf, size_t outlen)
{
struct efx_mcdi_iface *mcdi = efx_mcdi(efx);
unsigned int pdu = MCDI_PDU(efx);
unsigned int pdu = FR_CZ_MC_TREG_SMEM + MCDI_PDU(efx);
int i;
BUG_ON(atomic_read(&mcdi->state) == MCDI_STATE_QUIESCENT);
BUG_ON(outlen & 3 || outlen >= 0x100);
for (i = 0; i < outlen; i += 4)
efx_mcdi_readd(efx, (efx_dword_t *)(outbuf + i), pdu + 4 + i);
*((__le32 *)(outbuf + i)) = _efx_readd(efx, pdu + 4 + i);
}
static int efx_mcdi_poll(struct efx_nic *efx)
@ -135,7 +122,7 @@ static int efx_mcdi_poll(struct efx_nic *efx)
struct efx_mcdi_iface *mcdi = efx_mcdi(efx);
unsigned int time, finish;
unsigned int respseq, respcmd, error;
unsigned int pdu = MCDI_PDU(efx);
unsigned int pdu = FR_CZ_MC_TREG_SMEM + MCDI_PDU(efx);
unsigned int rc, spins;
efx_dword_t reg;
@ -161,7 +148,8 @@ static int efx_mcdi_poll(struct efx_nic *efx)
time = get_seconds();
efx_mcdi_readd(efx, &reg, pdu);
rmb();
efx_readd(efx, &reg, pdu);
/* All 1's indicates that shared memory is in reset (and is
* not a valid header). Wait for it to come out reset before
@ -188,7 +176,7 @@ static int efx_mcdi_poll(struct efx_nic *efx)
respseq, mcdi->seqno);
rc = EIO;
} else if (error) {
efx_mcdi_readd(efx, &reg, pdu + 4);
efx_readd(efx, &reg, pdu + 4);
switch (EFX_DWORD_FIELD(reg, EFX_DWORD_0)) {
#define TRANSLATE_ERROR(name) \
case MC_CMD_ERR_ ## name: \
@ -222,21 +210,21 @@ out:
/* Test and clear MC-rebooted flag for this port/function */
int efx_mcdi_poll_reboot(struct efx_nic *efx)
{
unsigned int addr = MCDI_REBOOT_FLAG(efx);
unsigned int addr = FR_CZ_MC_TREG_SMEM + MCDI_REBOOT_FLAG(efx);
efx_dword_t reg;
uint32_t value;
if (efx_nic_rev(efx) < EFX_REV_SIENA_A0)
return false;
efx_mcdi_readd(efx, &reg, addr);
efx_readd(efx, &reg, addr);
value = EFX_DWORD_FIELD(reg, EFX_DWORD_0);
if (value == 0)
return 0;
EFX_ZERO_DWORD(reg);
efx_mcdi_writed(efx, &reg, addr);
efx_writed(efx, &reg, addr);
if (value == MC_STATUS_DWORD_ASSERT)
return -EINTR;

7
drivers/net/sfc/nic.c
View file

@ -1936,13 +1936,6 @@ void efx_nic_get_regs(struct efx_nic *efx, void *buf)
size = min_t(size_t, table->step, 16);
if (table->offset >= efx->type->mem_map_size) {
/* No longer mapped; return dummy data */
memcpy(buf, "\xde\xc0\xad\xde", 4);
buf += table->rows * size;
continue;
}
for (i = 0; i < table->rows; i++) {
switch (table->step) {
case 4: /* 32-bit register or SRAM */

2
drivers/net/sfc/nic.h
View file

@ -143,12 +143,10 @@ static inline struct falcon_board *falcon_board(struct efx_nic *efx)
/**
* struct siena_nic_data - Siena NIC state
* @mcdi: Management-Controller-to-Driver Interface
* @mcdi_smem: MCDI shared memory mapping. The mapping is always uncacheable.
* @wol_filter_id: Wake-on-LAN packet filter id
*/
struct siena_nic_data {
struct efx_mcdi_iface mcdi;
void __iomem *mcdi_smem;
int wol_filter_id;
};

25
drivers/net/sfc/siena.c
View file

@ -250,26 +250,12 @@ static int siena_probe_nic(struct efx_nic *efx)
efx_reado(efx, &reg, FR_AZ_CS_DEBUG);
efx->net_dev->dev_id = EFX_OWORD_FIELD(reg, FRF_CZ_CS_PORT_NUM) - 1;
/* Initialise MCDI */
nic_data->mcdi_smem = ioremap_nocache(efx->membase_phys +
FR_CZ_MC_TREG_SMEM,
FR_CZ_MC_TREG_SMEM_STEP *
FR_CZ_MC_TREG_SMEM_ROWS);
if (!nic_data->mcdi_smem) {
netif_err(efx, probe, efx->net_dev,
"could not map MCDI at %llx+%x\n",
(unsigned long long)efx->membase_phys +
FR_CZ_MC_TREG_SMEM,
FR_CZ_MC_TREG_SMEM_STEP * FR_CZ_MC_TREG_SMEM_ROWS);
rc = -ENOMEM;
goto fail1;
}
efx_mcdi_init(efx);
/* Recover from a failed assertion before probing */
rc = efx_mcdi_handle_assertion(efx);
if (rc)
goto fail2;
goto fail1;
/* Let the BMC know that the driver is now in charge of link and
* filter settings. We must do this before we reset the NIC */
@ -324,7 +310,6 @@ fail4:
fail3:
efx_mcdi_drv_attach(efx, false, NULL);
fail2:
iounmap(nic_data->mcdi_smem);
fail1:
kfree(efx->nic_data);
return rc;
@ -404,8 +389,6 @@ static int siena_init_nic(struct efx_nic *efx)
static void siena_remove_nic(struct efx_nic *efx)
{
struct siena_nic_data *nic_data = efx->nic_data;
efx_nic_free_buffer(efx, &efx->irq_status);
siena_reset_hw(efx, RESET_TYPE_ALL);
@ -415,8 +398,7 @@ static void siena_remove_nic(struct efx_nic *efx)
efx_mcdi_drv_attach(efx, false, NULL);
/* Tear down the private nic state */
iounmap(nic_data->mcdi_smem);
kfree(nic_data);
kfree(efx->nic_data);
efx->nic_data = NULL;
}
@ -656,7 +638,8 @@ const struct efx_nic_type siena_a0_nic_type = {
.default_mac_ops = &efx_mcdi_mac_operations,
.revision = EFX_REV_SIENA_A0,
.mem_map_size = FR_CZ_MC_TREG_SMEM, /* MC_TREG_SMEM mapped separately */
.mem_map_size = (FR_CZ_MC_TREG_SMEM +
FR_CZ_MC_TREG_SMEM_STEP * FR_CZ_MC_TREG_SMEM_ROWS),
.txd_ptr_tbl_base = FR_BZ_TX_DESC_PTR_TBL,
.rxd_ptr_tbl_base = FR_BZ_RX_DESC_PTR_TBL,
.buf_tbl_base = FR_BZ_BUF_FULL_TBL,

2
drivers/net/sfc/workarounds.h
View file

@ -38,8 +38,6 @@
#define EFX_WORKAROUND_15783 EFX_WORKAROUND_ALWAYS
/* Legacy interrupt storm when interrupt fifo fills */
#define EFX_WORKAROUND_17213 EFX_WORKAROUND_SIENA
/* Write combining and sriov=enabled are incompatible */
#define EFX_WORKAROUND_22643 EFX_WORKAROUND_SIENA
/* Spurious parity errors in TSORT buffers */
#define EFX_WORKAROUND_5129 EFX_WORKAROUND_FALCON_A