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| author | Jon Mason <jon.mason@intel.com> | 2013-09-06 16:51:16 -0700 |
|---|---|---|
| committer | Jon Mason <jon.mason@intel.com> | 2013-11-20 09:57:30 -0700 |
| commit | c529aa30337b928bd6bc34293608cb3d4505856e (patch) | |
| tree | 48cb1e6180ecb243e923f65fa8436a7fa77db8f7 /drivers/ntb | |
| parent | 5e01dc7b26d9f24f39abace5da98ccbd6a5ceb52 (diff) | |
| download | linux-c529aa30337b928bd6bc34293608cb3d4505856e.tar.gz linux-c529aa30337b928bd6bc34293608cb3d4505856e.tar.bz2 linux-c529aa30337b928bd6bc34293608cb3d4505856e.zip | |
NTB: Xeon Doorbell errata workaround
Modifications to the 14th bit of the B2BDOORBELL register will not be
mirrored to the remote system due to a hardware issue. To get around
the issue, shrink the number of available doorbell bits by 1. The max
number of doorbells was being used as a way to referencing the Link
Doorbell bit. Since this would no longer work, the driver must now
explicitly reference that bit.
This does not affect the xeon_errata_workaround case, as it is not using
the b2bdoorbell register.
Signed-off-by: Jon Mason <jon.mason@intel.com>
Diffstat (limited to 'drivers/ntb')
| -rw-r--r-- | drivers/ntb/ntb_hw.c | 20 | ||||
| -rw-r--r-- | drivers/ntb/ntb_regs.h | 1 |
2 files changed, 16 insertions, 5 deletions
diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c index 1cb6e51e6bda..6c9d73348735 100644 --- a/drivers/ntb/ntb_hw.c +++ b/drivers/ntb/ntb_hw.c @@ -678,6 +678,7 @@ static int ntb_xeon_setup(struct ntb_device *ndev) return -EINVAL; ndev->limits.max_mw = SNB_ERRATA_MAX_MW; + ndev->limits.max_db_bits = SNB_MAX_DB_BITS; ndev->reg_ofs.spad_write = ndev->mw[1].vbase + SNB_SPAD_OFFSET; ndev->reg_ofs.rdb = ndev->mw[1].vbase + @@ -690,6 +691,13 @@ static int ntb_xeon_setup(struct ntb_device *ndev) SNB_PBAR4LMT_OFFSET); } else { ndev->limits.max_mw = SNB_MAX_MW; + + /* HW Errata on bit 14 of b2bdoorbell register. Writes + * will not be mirrored to the remote system. Shrink + * the number of bits by one, since bit 14 is the last + * bit. + */ + ndev->limits.max_db_bits = SNB_MAX_DB_BITS - 1; ndev->reg_ofs.spad_write = ndev->reg_base + SNB_B2B_SPAD_OFFSET; ndev->reg_ofs.rdb = ndev->reg_base + @@ -769,6 +777,7 @@ static int ntb_xeon_setup(struct ntb_device *ndev) * have an equal amount. */ ndev->limits.max_spads = SNB_MAX_COMPAT_SPADS / 2; + ndev->limits.max_db_bits = SNB_MAX_DB_BITS; /* Note: The SDOORBELL is the cause of the errata. You REALLY * don't want to touch it. */ @@ -793,6 +802,7 @@ static int ntb_xeon_setup(struct ntb_device *ndev) * have an equal amount. */ ndev->limits.max_spads = SNB_MAX_COMPAT_SPADS / 2; + ndev->limits.max_db_bits = SNB_MAX_DB_BITS; ndev->reg_ofs.rdb = ndev->reg_base + SNB_PDOORBELL_OFFSET; ndev->reg_ofs.ldb = ndev->reg_base + SNB_SDOORBELL_OFFSET; ndev->reg_ofs.ldb_mask = ndev->reg_base + SNB_SDBMSK_OFFSET; @@ -819,7 +829,6 @@ static int ntb_xeon_setup(struct ntb_device *ndev) ndev->reg_ofs.lnk_stat = ndev->reg_base + SNB_SLINK_STATUS_OFFSET; ndev->reg_ofs.spci_cmd = ndev->reg_base + SNB_PCICMD_OFFSET; - ndev->limits.max_db_bits = SNB_MAX_DB_BITS; ndev->limits.msix_cnt = SNB_MSIX_CNT; ndev->bits_per_vector = SNB_DB_BITS_PER_VEC; @@ -986,7 +995,7 @@ static irqreturn_t xeon_event_msix_irq(int irq, void *dev) dev_err(&ndev->pdev->dev, "Error determining link status\n"); /* bit 15 is always the link bit */ - writew(1 << ndev->limits.max_db_bits, ndev->reg_ofs.ldb); + writew(1 << SNB_LINK_DB, ndev->reg_ofs.ldb); return IRQ_HANDLED; } @@ -1176,9 +1185,10 @@ static int ntb_setup_interrupts(struct ntb_device *ndev) */ if (ndev->hw_type == BWD_HW) writeq(~0, ndev->reg_ofs.ldb_mask); - else - writew(~(1 << ndev->limits.max_db_bits), - ndev->reg_ofs.ldb_mask); + else { + u16 var = 1 << SNB_LINK_DB; + writew(~var, ndev->reg_ofs.ldb_mask); + } rc = ntb_setup_msix(ndev); if (!rc) diff --git a/drivers/ntb/ntb_regs.h b/drivers/ntb/ntb_regs.h index aa4bdd393c58..5381b65a6f3a 100644 --- a/drivers/ntb/ntb_regs.h +++ b/drivers/ntb/ntb_regs.h @@ -55,6 +55,7 @@ #define SNB_MAX_COMPAT_SPADS 16 /* Reserve the uppermost bit for link interrupt */ #define SNB_MAX_DB_BITS 15 +#define SNB_LINK_DB 15 #define SNB_DB_BITS_PER_VEC 5 #define SNB_MAX_MW 2 #define SNB_ERRATA_MAX_MW 1 |