On 7/4/21 10:28 PM, Pali Rohár wrote:
+ Bjorn, Krzysztof and linux-pci
On Friday 02 July 2021 12:51:19 Aaron Ma wrote:
Check PCI state when rd/wr iomem.
Implement wr32 function as rd32 too.
When unplug TBT dock with i225, rd/wr PCI iomem will cause error log:
Trace:
BUG: unable to handle page fault for address: 000000000000b604
Oops: 0000 [#1] SMP NOPTI
RIP: 0010:igc_rd32+0x1c/0x90 [igc]
Call Trace:
igc_ptp_suspend+0x6c/0xa0 [igc]
igc_ptp_stop+0x12/0x50 [igc]
igc_remove+0x7f/0x1c0 [igc]
pci_device_remove+0x3e/0xb0
__device_release_driver+0x181/0x240
Signed-off-by: Aaron Ma <aaron.ma@xxxxxxxxxxxxx>
---
drivers/net/ethernet/intel/igc/igc_main.c | 16 ++++++++++++++++
drivers/net/ethernet/intel/igc/igc_regs.h | 7 ++-----
2 files changed, 18 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index f1adf154ec4a..606b72cb6193 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -5292,6 +5292,10 @@ u32 igc_rd32(struct igc_hw *hw, u32 reg)
u8 __iomem *hw_addr = READ_ONCE(hw->hw_addr);
u32 value = 0;
+ if (igc->pdev &&
+ igc->pdev->error_state == pci_channel_io_perm_failure)
Hello! This code pattern and commit message looks like that we could use
pci_dev_is_disconnected() helper function for checking if device is
still connected or was disconnected.
Apparently pci_dev_is_disconnected() is defined only in private header
file drivers/pci/pci.h and not in public include/linux/pci.h.
Aaron: can you check if pci_dev_is_disconnected() is really something
which should be used and it helps you?
Hi Pali,
How about using pci_channel_offline instead?
It's ready and also safe for frozen state, and verified on hw.
Bjorn, Krzysztof: what do you think about lifting helper function
pci_dev_is_disconnected() to be available to all drivers and not only in
PCI subsystem?
I think that such helper function makes driver code more readable and
can be useful also for other drivers which are checking if return value
is all F's.
+ return 0;
Aaron: should not you return all F's on error? Because few lines below
in this function is returned value with all F's when PCIe link lost.
If you agree with the above change, I can fix it to "return -1" in v2.
Thanks for your comments,
Aaron
+
value = readl(&hw_addr[reg]);
Anyway, this code looks to be racy. When pci_channel_io_perm_failure is
set (e.g. by hotplug interrupt) after checking for pdev->error_state and
prior executing above readl() then mentioned fatal error still occurs.
/* reads should not return all F's */
@@ -5308,6 +5312,18 @@ u32 igc_rd32(struct igc_hw *hw, u32 reg)
return value;
}
+void igc_wr32(struct igc_hw *hw, u32 reg, u32 val)
+{
+ struct igc_adapter *igc = container_of(hw, struct igc_adapter, hw);
+ u8 __iomem *hw_addr = READ_ONCE(hw->hw_addr);
+
+ if (igc->pdev &&
+ igc->pdev->error_state == pci_channel_io_perm_failure)
+ return;
+
+ writel((val), &hw_addr[(reg)]);
+}
+
int igc_set_spd_dplx(struct igc_adapter *adapter, u32 spd, u8 dplx)
{
struct igc_mac_info *mac = &adapter->hw.mac;
diff --git a/drivers/net/ethernet/intel/igc/igc_regs.h b/drivers/net/ethernet/intel/igc/igc_regs.h
index cc174853554b..eb4be87d0e8b 100644
--- a/drivers/net/ethernet/intel/igc/igc_regs.h
+++ b/drivers/net/ethernet/intel/igc/igc_regs.h
@@ -260,13 +260,10 @@ struct igc_hw;
u32 igc_rd32(struct igc_hw *hw, u32 reg);
/* write operations, indexed using DWORDS */
-#define wr32(reg, val) \
-do { \
- u8 __iomem *hw_addr = READ_ONCE((hw)->hw_addr); \
- writel((val), &hw_addr[(reg)]); \
-} while (0)
+void igc_wr32(struct igc_hw *hw, u32 reg, u32 val);
#define rd32(reg) (igc_rd32(hw, reg))
+#define wr32(reg, val) (igc_wr32(hw, reg, val))
#define wrfl() ((void)rd32(IGC_STATUS))
--
2.30.2
