[012/126] EISA/PCI: Fix bus res reference

Steven Rostedt
2013-05-07T04:11:40Z

[-- Attachment #1: 0012-EISA-PCI-Fix-bus-res-reference.patch --]
[-- Type: text/plain, Size: 3066 bytes --]

3.6.11.3 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Yinghai Lu <yinghai@kernel.org>

[ Upstream commit 2cfda637e29ce9e3df31b59f64516b2e571cc985 ]

Matthew found that 3.8.3 is having problems with an old (ancient)
PCI-to-EISA bridge, the Intel 82375. It worked with the 3.2 kernel.
He identified the 82375, but doesn't assign the struct resource *res
pointer inside the struct eisa_root_device, and panics.

pci_eisa_init() was using bus->resource[] directly instead of
pci_bus_resource_n(). The bus->resource[] array is a PCI-internal
implementation detail, and after commit 45ca9e97 (PCI: add helpers for
building PCI bus resource lists) and commit 0efd5aab (PCI: add struct
pci_host_bridge_window with CPU/bus address offset), bus->resource[] is not
used for PCI root buses any more.

The 82375 is a subtractive-decode PCI device, so handle it the same
way we handle PCI-PCI bridges in subtractive-decode mode in
pci_read_bridge_bases().

[bhelgaas: changelog]
Reported-by: Matthew Whitehead <mwhitehe@redhat.com>
Tested-by: Matthew Whitehead <mwhitehe@redhat.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org # v3.3+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
drivers/eisa/pci_eisa.c | 28 +++++++++++++++++++++++++---
1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/drivers/eisa/pci_eisa.c b/drivers/eisa/pci_eisa.c
index d4cd56a..6c3fca9 100644
--- a/drivers/eisa/pci_eisa.c
+++ b/drivers/eisa/pci_eisa.c
@@ -21,7 +21,8 @@ static struct eisa_root_device pci_eisa_root;

static int __init pci_eisa_init(struct pci_dev *pdev)
{
- int rc;
+ int rc, i;
+ struct resource *res, *bus_res = NULL;

if ((rc = pci_enable_device (pdev))) {
printk (KERN_ERR "pci_eisa : Could not enable device %s\n",
@@ -29,9 +30,30 @@ static int __init pci_eisa_init(struct pci_dev *pdev)
return rc;
}

+ /*
+ * The Intel 82375 PCI-EISA bridge is a subtractive-decode PCI
+ * device, so the resources available on EISA are the same as those
+ * available on the 82375 bus. This works the same as a PCI-PCI
+ * bridge in subtractive-decode mode (see pci_read_bridge_bases()).
+ * We assume other PCI-EISA bridges are similar.
+ *
+ * eisa_root_register() can only deal with a single io port resource,
+ * so we use the first valid io port resource.
+ */
+ pci_bus_for_each_resource(pdev->bus, res, i)
+ if (res && (res->flags & IORESOURCE_IO)) {
+ bus_res = res;
+ break;
+ }
+
+ if (!bus_res) {
+ dev_err(&pdev->dev, "No resources available\n");
+ return -1;
+ }
+
pci_eisa_root.dev = &pdev->dev;
- pci_eisa_root.res = pdev->bus->resource[0];
- pci_eisa_root.bus_base_addr = pdev->bus->resource[0]->start;
+ pci_eisa_root.res = bus_res;
+ pci_eisa_root.bus_base_addr = bus_res->start;
pci_eisa_root.slots = EISA_MAX_SLOTS;
pci_eisa_root.dma_mask = pdev->dma_mask;
dev_set_drvdata(pci_eisa_root.dev, &pci_eisa_root);
--
1.7.10.4