From: Ard Biesheuvel ard.biesheuvel@linaro.org
[ Upstream commit 3a8ecc935efabdad106b5e06d07b150c394b4465 ]
Commit 7fd8930f26be4
"nvme: add a common helper to read Identify Controller data"
has re-introduced an issue that we have attempted to work around in the past, in commit a310acd7a7ea ("NVMe: use split lo_hi_{read,write}q").
The problem is that some PCIe NVMe controllers do not implement 64-bit outbound accesses correctly, which is why the commit above switched to using lo_hi_[read|write]q for all 64-bit BAR accesses occuring in the code.
In the mean time, the NVMe subsystem has been refactored, and now calls into the PCIe support layer for NVMe via a .reg_read64() method, which fails to use lo_hi_readq(), and thus reintroduces the problem that the workaround above aimed to address.
Given that, at the moment, .reg_read64() is only used to read the capability register [which is known to tolerate split reads], let's switch .reg_read64() to lo_hi_readq() as well.
This fixes a boot issue on some ARM boxes with NVMe behind a Synopsys DesignWare PCIe host controller.
Fixes: 7fd8930f26be4 ("nvme: add a common helper to read Identify Controller data") Signed-off-by: Ard Biesheuvel ard.biesheuvel@linaro.org Signed-off-by: Sagi Grimberg sagi@grimberg.me Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/nvme/host/pci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index 124f41157173..3c68a5b35ec1 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -2396,7 +2396,7 @@ static int nvme_pci_reg_write32(struct nvme_ctrl *ctrl, u32 off, u32 val)
static int nvme_pci_reg_read64(struct nvme_ctrl *ctrl, u32 off, u64 *val) { - *val = readq(to_nvme_dev(ctrl)->bar + off); + *val = lo_hi_readq(to_nvme_dev(ctrl)->bar + off); return 0; }