From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sasha Levin <sashal@kernel.org>, Sagi Grimberg <sagi@grimberg.me>,
linux-nvme@lists.infradead.org,
Ard Biesheuvel <ard.biesheuvel@linaro.org>
Subject: [PATCH AUTOSEL 4.9 209/251] nvme: retain split access workaround for capability reads
Date: Thu, 16 Jan 2020 12:35:58 -0500 [thread overview]
Message-ID: <20200116173641.22137-169-sashal@kernel.org> (raw)
In-Reply-To: <20200116173641.22137-1-sashal@kernel.org>
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 1ac4cec5f4f7..e2bce9385eda 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1863,7 +1863,7 @@ 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;
}
--
2.20.1
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parent reply other threads:[~2020-01-16 18:25 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <20200116173641.22137-1-sashal@kernel.org>]
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