From: Doug Meyer dmeyer@gigaio.com
[ Upstream commit 140eb5227767c6754742020a16d2691222b9c19b ]
This resolves a bug which may incorrectly configure the peer host's LUT for shared memory window access. The code was using the local host's first BAR number, rather than the peer hosts's first BAR number, to determine what peer NT control register to program.
The bug will cause the Switchtec NTB link to work only if both peers have the same first NTB BAR configured. In all other configurations, the link will not come up, failing silently.
When both hosts have the same first BAR, the configuration works only because the first BAR numbers happent to be the same. When the hosts do not have the same first BAR, then the LUT translation will not be configured in the correct peer LUT and will not give the peer the shared memory window access required for the link to operate.
Signed-off-by: Doug Meyer dmeyer@gigaio.com Reviewed-by: Logan Gunthorpe logang@deltatee.com Fixes: 678784a44ae8 ("NTB: switchtec_ntb: Initialize hardware for memory windows") Signed-off-by: Jon Mason jdmason@kudzu.us Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- drivers/ntb/hw/mscc/ntb_hw_switchtec.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/ntb/hw/mscc/ntb_hw_switchtec.c b/drivers/ntb/hw/mscc/ntb_hw_switchtec.c index afe8ed6f3b23..ca0334a6b759 100644 --- a/drivers/ntb/hw/mscc/ntb_hw_switchtec.c +++ b/drivers/ntb/hw/mscc/ntb_hw_switchtec.c @@ -964,7 +964,8 @@ static void switchtec_ntb_init_shared(struct switchtec_ntb *sndev) static int switchtec_ntb_init_shared_mw(struct switchtec_ntb *sndev) { struct ntb_ctrl_regs __iomem *ctl = sndev->mmio_peer_ctrl; - int bar = sndev->direct_mw_to_bar[0]; + int self_bar = sndev->direct_mw_to_bar[0]; + int peer_bar = sndev->peer_direct_mw_to_bar[0]; u32 ctl_val; int rc;
@@ -985,12 +986,12 @@ static int switchtec_ntb_init_shared_mw(struct switchtec_ntb *sndev) if (rc) goto unalloc_and_exit;
- ctl_val = ioread32(&ctl->bar_entry[bar].ctl); + ctl_val = ioread32(&ctl->bar_entry[peer_bar].ctl); ctl_val &= 0xFF; ctl_val |= NTB_CTRL_BAR_LUT_WIN_EN; ctl_val |= ilog2(LUT_SIZE) << 8; ctl_val |= (sndev->nr_lut_mw - 1) << 14; - iowrite32(ctl_val, &ctl->bar_entry[bar].ctl); + iowrite32(ctl_val, &ctl->bar_entry[peer_bar].ctl);
iowrite64((NTB_CTRL_LUT_EN | (sndev->self_partition << 1) | sndev->self_shared_dma), @@ -1009,7 +1010,7 @@ static int switchtec_ntb_init_shared_mw(struct switchtec_ntb *sndev) goto unalloc_and_exit; }
- sndev->peer_shared = pci_iomap(sndev->stdev->pdev, bar, LUT_SIZE); + sndev->peer_shared = pci_iomap(sndev->stdev->pdev, self_bar, LUT_SIZE); if (!sndev->peer_shared) { rc = -ENOMEM; goto unalloc_and_exit;