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authorHelge Deller <deller@gmx.de>2018-03-25 14:04:22 +0200
committerHelge Deller <deller@gmx.de>2018-03-27 18:52:22 +0200
commitb845f66f78bf42a4ce98e5cfe0e94fab41dd0742 (patch)
treef146133732045dcdf83ec6434a587a447c418c5a /drivers/parisc/lba_pci.c
parentd5654e156bc4d68a87bbaa6d7e020baceddf6e68 (diff)
parisc/pci: Switch LBA PCI bus from Hard Fail to Soft Fail mode
Carlo Pisani noticed that his C3600 workstation behaved unstable during heavy I/O on the PCI bus with a VIA VT6421 IDE/SATA PCI card. To avoid such instability, this patch switches the LBA PCI bus from Hard Fail mode into Soft Fail mode. In this mode the bus will return -1UL for timed out MMIO transactions, which is exactly how the x86 (and most other architectures) PCI busses behave. This patch is based on a proposal by Grant Grundler and Kyle McMartin 10 years ago: https://www.spinics.net/lists/linux-parisc/msg01027.html Cc: Carlo Pisani <carlojpisani@gmail.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Reviewed-by: Grant Grundler <grantgrundler@gmail.com> Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'drivers/parisc/lba_pci.c')
-rw-r--r--drivers/parisc/lba_pci.c20
1 files changed, 19 insertions, 1 deletions
diff --git a/drivers/parisc/lba_pci.c b/drivers/parisc/lba_pci.c
index 41b740aed3a3..69bd98421eb1 100644
--- a/drivers/parisc/lba_pci.c
+++ b/drivers/parisc/lba_pci.c
@@ -1403,9 +1403,27 @@ lba_hw_init(struct lba_device *d)
WRITE_REG32(stat, d->hba.base_addr + LBA_ERROR_CONFIG);
}
- /* Set HF mode as the default (vs. -1 mode). */
+
+ /*
+ * Hard Fail vs. Soft Fail on PCI "Master Abort".
+ *
+ * "Master Abort" means the MMIO transaction timed out - usually due to
+ * the device not responding to an MMIO read. We would like HF to be
+ * enabled to find driver problems, though it means the system will
+ * crash with a HPMC.
+ *
+ * In SoftFail mode "~0L" is returned as a result of a timeout on the
+ * pci bus. This is like how PCI busses on x86 and most other
+ * architectures behave. In order to increase compatibility with
+ * existing (x86) PCI hardware and existing Linux drivers we enable
+ * Soft Faul mode on PA-RISC now too.
+ */
stat = READ_REG32(d->hba.base_addr + LBA_STAT_CTL);
+#if defined(ENABLE_HARDFAIL)
WRITE_REG32(stat | HF_ENABLE, d->hba.base_addr + LBA_STAT_CTL);
+#else
+ WRITE_REG32(stat & ~HF_ENABLE, d->hba.base_addr + LBA_STAT_CTL);
+#endif
/*
** Writing a zero to STAT_CTL.rf (bit 0) will clear reset signal