On 25/10/12 23:06, H Hartley Sweeten wrote:
Factor out the code in me_attach_pci() that handles the PLX-Bug
workaround to a separate function.
This looks odd. It appears that the bug workaround either swaps
PCI bars 0 and 5 or it modifies PCI bar 0. Shouldn't this happen
before PCI bar 0 is ioremap'ed?
Yes, the workaround is wrong as it ends up ioremap'ing the wrong
address. It should ioremap whatever gets written to the
PCI_BASE_ADDRESS_0 config dword, or the original
pci_resource_start(pcidev, 0) value if no workaround is needed.
The workaround is pretty dodgy anyway and should be done by
pci/quirks.c. The case where it subtracts 0x80 before writing back is
particularly dodgy as it is likely to screw up other devices in the system.
There is a hardware bug in the PLX PCI 9050 that means its local
configuration registers cannot be read through PCI BAR 0 if bit 7 of PCI
BAR 0 is set - the local configuration registers would read back as 0.
The same applies to PCI BAR 1. PCI BAR 0 is memory of size 128 or 0
(disabled); PCI BAR 1 is I/O of size 128 or 0 (disabled). If not
disabled, they both map to the chip's local configuration registers.
The _real_ fix at the hardware design level is to replace the PCI 9050
with a PCI 9052 in subsequent issues of the hardware.
Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/drivers/me_daq.c | 95 ++++++++++++++++-----------------
1 file changed, 47 insertions(+), 48 deletions(-)
diff --git a/drivers/staging/comedi/drivers/me_daq.c b/drivers/staging/comedi/drivers/me_daq.c
index 95fbecc..182a184 100644
--- a/drivers/staging/comedi/drivers/me_daq.c
+++ b/drivers/staging/comedi/drivers/me_daq.c
@@ -617,6 +617,48 @@ static int me_reset(struct comedi_device *dev)
return 0;
}
+static int me_plx_bug_check(struct comedi_device *dev,
+ struct pci_dev *pcidev)
+{
+ resource_size_t plx_regbase_tmp = pci_resource_start(pcidev, 0);
+ resource_size_t swap_regbase_tmp = pci_resource_start(pcidev, 5);
+ resource_size_t regbase_tmp;
+ int ret;
+
+ if (!swap_regbase_tmp)
+ dev_err(dev->class_dev, "Swap not present\n");
+
+ if (plx_regbase_tmp & 0x0080) {
+ dev_err(dev->class_dev, "PLX-Bug detected\n");
+
+ if (swap_regbase_tmp) {
+ regbase_tmp = plx_regbase_tmp;
+ plx_regbase_tmp = swap_regbase_tmp;
+ swap_regbase_tmp = regbase_tmp;
+
+ ret = pci_write_config_dword(pcidev,
+ PCI_BASE_ADDRESS_0,
+ plx_regbase_tmp);
+ if (ret != PCIBIOS_SUCCESSFUL)
+ return -EIO;
+
+ ret = pci_write_config_dword(pcidev,
+ PCI_BASE_ADDRESS_5,
+ swap_regbase_tmp);
+ if (ret != PCIBIOS_SUCCESSFUL)
+ return -EIO;
+ } else {
+ plx_regbase_tmp -= 0x80;
+ ret = pci_write_config_dword(pcidev,
+ PCI_BASE_ADDRESS_0,
+ plx_regbase_tmp);
+ if (ret != PCIBIOS_SUCCESSFUL)
+ return -EIO;
+ }
+ }
+ return 0;
+}
+
static const void *me_find_boardinfo(struct comedi_device *dev,
struct pci_dev *pcidev)
{
@@ -636,10 +678,6 @@ static int me_attach_pci(struct comedi_device *dev, struct pci_dev *pcidev)
const struct me_board *board;
struct me_private_data *dev_private;
struct comedi_subdevice *s;
- resource_size_t plx_regbase_tmp;
- resource_size_t swap_regbase_tmp;
- unsigned long swap_regbase_size_tmp;
- resource_size_t regbase_tmp;
int ret;
board = me_find_boardinfo(dev, pcidev);
@@ -658,53 +696,14 @@ static int me_attach_pci(struct comedi_device *dev, struct pci_dev *pcidev)
return ret;
dev->iobase = 1; /* detach needs this */
- /* Read PLX register base address [PCI_BASE_ADDRESS #0]. */
- plx_regbase_tmp = pci_resource_start(pcidev, 0);
- dev_private->plx_regbase = ioremap(plx_regbase_tmp,
+ dev_private->plx_regbase = ioremap(pci_resource_start(pcidev, 0),
pci_resource_len(pcidev, 0));
- if (!dev_private->plx_regbase) {
- dev_err(dev->class_dev, "Failed to remap I/O memory\n");
+ if (!dev_private->plx_regbase)
return -ENOMEM;
- }
-
- /* Read Swap base address [PCI_BASE_ADDRESS #5]. */
-
- swap_regbase_tmp = pci_resource_start(pcidev, 5);
- swap_regbase_size_tmp = pci_resource_len(pcidev, 5);
-
- if (!swap_regbase_tmp)
- dev_err(dev->class_dev, "Swap not present\n");
-
- /*---------------------------------------------- Workaround start ---*/
- if (plx_regbase_tmp & 0x0080) {
- dev_err(dev->class_dev, "PLX-Bug detected\n");
-
- if (swap_regbase_tmp) {
- regbase_tmp = plx_regbase_tmp;
- plx_regbase_tmp = swap_regbase_tmp;
- swap_regbase_tmp = regbase_tmp;
- ret = pci_write_config_dword(pcidev,
- PCI_BASE_ADDRESS_0,
- plx_regbase_tmp);
- if (ret != PCIBIOS_SUCCESSFUL)
- return -EIO;
-
- ret = pci_write_config_dword(pcidev,
- PCI_BASE_ADDRESS_5,
- swap_regbase_tmp);
- if (ret != PCIBIOS_SUCCESSFUL)
- return -EIO;
- } else {
- plx_regbase_tmp -= 0x80;
- ret = pci_write_config_dword(pcidev,
- PCI_BASE_ADDRESS_0,
- plx_regbase_tmp);
- if (ret != PCIBIOS_SUCCESSFUL)
- return -EIO;
- }
- }
- /*--------------------------------------------- Workaround end -----*/
+ ret = me_plx_bug_check(dev, pcidev);
+ if (ret)
+ return ret;
dev_private->me_regbase = ioremap(pci_resource_start(pcidev, 2),
pci_resource_len(pcidev, 2));
--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@xxxxxxxxx> )=-
-=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
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