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| author | Helge Deller <deller@gmx.de> | 2018-03-25 14:04:22 +0200 |
|---|---|---|
| committer | Helge Deller <deller@gmx.de> | 2018-03-27 18:52:22 +0200 |
| commit | b845f66f78bf42a4ce98e5cfe0e94fab41dd0742 (patch) | |
| tree | f146133732045dcdf83ec6434a587a447c418c5a /drivers | |
| parent | d5654e156bc4d68a87bbaa6d7e020baceddf6e68 (diff) | |
| download | linux-rpi-b845f66f78bf42a4ce98e5cfe0e94fab41dd0742.tar.gz linux-rpi-b845f66f78bf42a4ce98e5cfe0e94fab41dd0742.tar.bz2 linux-rpi-b845f66f78bf42a4ce98e5cfe0e94fab41dd0742.zip | |
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')
| -rw-r--r-- | drivers/parisc/lba_pci.c | 20 |
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 |