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m68k/PCI: Use pci_enable_resources() in pcibios_enable_device() 

m68k has a resource enable (check) loop in its pcibios_enable_device()
which for some reason differs from pci_enable_resources(). This could lead
to inconsistencies in behavior, especially now as pci_enable_resources()
and the bridge window resource flags behavior are going to be altered by
upcoming changes.

The check for !r->start && r->end is already covered by the more generic
checks done in pci_enable_resources().

The entire pcibios_enable_device() suspiciously looks copy-paste from some
other arch as also indicated by the preceding comment. However, it also
enables PCI_COMMAND_IO | PCI_COMMAND_MEMORY always for bridges. It is not
clear why that is being done as the commit e93a6bbeb5 ("m68k: common PCI
support definitions and code") introducing this code states "Nothing
specific to any PCI implementation in any m68k class CPU hardware yet".

Replace the resource enable loop with a call to pci_enable_resources() and
adjust the Command Register afterwards as it's unclear if that is necessary
or not so keep it for now.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20250829131113.36754-2-ilpo.jarvinen@linux.intel.com
This commit is contained in:
Ilpo Järvinen 2025-08-29 16:10:50 +03:00 committed by Bjorn Helgaas
parent 31af09b3ea
commit 2657a0c982
1 changed files with 11 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
arch/m68k/kernel/pcibios.c
View File

@ -44,41 +44,24 @@ resource_size_t pcibios_align_resource(void *data, const struct resource *res,
*/
int pcibios_enable_device(struct pci_dev *dev, int mask)
{
struct resource *r;
u16 cmd, newcmd;
int idx;
int ret;
pci_read_config_word(dev, PCI_COMMAND, &cmd);
newcmd = cmd;
for (idx = 0; idx < 6; idx++) {
/* Only set up the requested stuff */
if (!(mask & (1 << idx)))
continue;
r = dev->resource + idx;
if (!r->start && r->end) {
pr_err("PCI: Device %s not available because of resource collisions\n",
pci_name(dev));
return -EINVAL;
}
if (r->flags & IORESOURCE_IO)
newcmd |= PCI_COMMAND_IO;
if (r->flags & IORESOURCE_MEM)
newcmd |= PCI_COMMAND_MEMORY;
}
ret = pci_enable_resources(dev, mask);
if (ret < 0)
return ret;
/*
* Bridges (eg, cardbus bridges) need to be fully enabled
*/
if ((dev->class >> 16) == PCI_BASE_CLASS_BRIDGE)
if ((dev->class >> 16) == PCI_BASE_CLASS_BRIDGE) {
pci_read_config_word(dev, PCI_COMMAND, &cmd);
newcmd |= PCI_COMMAND_IO | PCI_COMMAND_MEMORY;
if (newcmd != cmd) {
pr_info("PCI: enabling device %s (0x%04x -> 0x%04x)\n",
pci_name(dev), cmd, newcmd);
pci_write_config_word(dev, PCI_COMMAND, newcmd);
if (newcmd != cmd) {
pr_info("PCI: enabling bridge %s (0x%04x -> 0x%04x)\n",
pci_name(dev), cmd, newcmd);
pci_write_config_word(dev, PCI_COMMAND, newcmd);
}
}
return 0;
}