path: root/drivers/pnp/core.c
diff options
authorBjorn Helgaas <bjorn.helgaas@hp.com>2008-06-27 16:57:17 -0600
committerAndi Kleen <andi@basil.nowhere.org>2008-07-16 23:27:07 +0200
commit1f32ca31e7409d37c1b25e5f81840fb184380cdf (patch)
treee587c85b46b04dbbb5987e2a4986ab174f3bd6fa /drivers/pnp/core.c
parentbbe413b4fc7f791248c7ee00ce7b3778491a3700 (diff)
PNP: convert resource options to single linked list
ISAPNP, PNPBIOS, and ACPI describe the "possible resource settings" of a device, i.e., the possibilities an OS bus driver has when it assigns I/O port, MMIO, and other resources to the device. PNP used to maintain this "possible resource setting" information in one independent option structure and a list of dependent option structures for each device. Each of these option structures had lists of I/O, memory, IRQ, and DMA resources, for example: dev independent options ind-io0 -> ind-io1 ... ind-mem0 -> ind-mem1 ... ... dependent option set 0 dep0-io0 -> dep0-io1 ... dep0-mem0 -> dep0-mem1 ... ... dependent option set 1 dep1-io0 -> dep1-io1 ... dep1-mem0 -> dep1-mem1 ... ... ... This data structure was designed for ISAPNP, where the OS configures device resource settings by writing directly to configuration registers. The OS can write the registers in arbitrary order much like it writes PCI BARs. However, for PNPBIOS and ACPI devices, the OS uses firmware interfaces that perform device configuration, and it is important to pass the desired settings to those interfaces in the correct order. The OS learns the correct order by using firmware interfaces that return the "current resource settings" and "possible resource settings," but the option structures above doesn't store the ordering information. This patch replaces the independent and dependent lists with a single list of options. For example, a device might have possible resource settings like this: dev options ind-io0 -> dep0-io0 -> dep1->io0 -> ind-io1 ... All the possible settings are in the same list, in the order they come from the firmware "possible resource settings" list. Each entry is tagged with an independent/dependent flag. Dependent entries also have a "set number" and an optional priority value. All dependent entries must be assigned from the same set. For example, the OS can use all the entries from dependent set 0, or all the entries from dependent set 1, but it cannot mix entries from set 0 with entries from set 1. Prior to this patch PNP didn't keep track of the order of this list, and it assigned all independent options first, then all dependent ones. Using the example above, that resulted in a "desired configuration" list like this: ind->io0 -> ind->io1 -> depN-io0 ... instead of the list the firmware expects, which looks like this: ind->io0 -> depN-io0 -> ind-io1 ... Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Rene Herman <rene.herman@gmail.com> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/pnp/core.c')
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/pnp/core.c b/drivers/pnp/core.c
index 7182da92aec3..a411582bcd72 100644
--- a/drivers/pnp/core.c
+++ b/drivers/pnp/core.c
@@ -118,10 +118,9 @@ static void pnp_release_device(struct device *dmdev)
struct pnp_dev *dev = to_pnp_dev(dmdev);
- pnp_free_option(dev->independent);
- pnp_free_option(dev->dependent);
+ pnp_free_options(dev);
@@ -135,6 +134,7 @@ struct pnp_dev *pnp_alloc_dev(struct pnp_protocol *protocol, int id, char *pnpid
return NULL;
+ INIT_LIST_HEAD(&dev->options);
dev->protocol = protocol;
dev->number = id;
dev->dma_mask = DMA_24BIT_MASK;

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