From d88d6b05fee3cc78e5b0273eb58c31201dcc6b76 Mon Sep 17 00:00:00 2001 From: Steve Hodgson Date: Tue, 22 Mar 2011 19:46:43 +0000 Subject: [PATCH] sfc: Siena: Disable write-combining when SR-IOV is enabled If SR-IOV is enabled by firmware, even if it is not enabled in the PCI capability, TX pushes using write-combining may be corrupted. We want to know whether it is enabled before mapping the NIC registers, and even if PCI extended capabilities are not accessible. Therefore, we look for the MSI capability, which is removed if SR-IOV is enabled. Signed-off-by: Ben Hutchings --- drivers/net/sfc/efx.c | 18 ++++++++++++++++-- drivers/net/sfc/workarounds.h | 2 ++ 2 files changed, 18 insertions(+), 2 deletions(-) diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c index b8bd936374f2..d890679e4c4d 100644 --- a/drivers/net/sfc/efx.c +++ b/drivers/net/sfc/efx.c @@ -1054,6 +1054,7 @@ 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"); @@ -1104,8 +1105,21 @@ static int efx_init_io(struct efx_nic *efx) rc = -EIO; goto fail3; } - efx->membase = ioremap_wc(efx->membase_phys, - efx->type->mem_map_size); + + /* 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); if (!efx->membase) { netif_err(efx, probe, efx->net_dev, "could not map memory BAR at %llx+%x\n", diff --git a/drivers/net/sfc/workarounds.h b/drivers/net/sfc/workarounds.h index e4dd3a7f304b..99ff11400cef 100644 --- a/drivers/net/sfc/workarounds.h +++ b/drivers/net/sfc/workarounds.h @@ -38,6 +38,8 @@ #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