PCI: clean up resource alignment management

Done per Linus' request and suggestions. Linus has explained that
better than I'll be able to explain:

On Thu, Mar 27, 2008 at 10:12:10AM -0700, Linus Torvalds wrote:
> Actually, before we go any further, there might be a less intrusive
> alternative: add just a couple of flags to the resource flags field (we
> still have something like 8 unused bits on 32-bit), and use those to
> implement a generic "resource_alignment()" routine.
>
> Two flags would do it:
>
>  - IORESOURCE_SIZEALIGN: size indicates alignment (regular PCI device
>    resources)
>
>  - IORESOURCE_STARTALIGN: start field is alignment (PCI bus resources
>    during probing)
>
> and then the case of both flags zero (or both bits set) would actually be
> "invalid", and we would also clear the IORESOURCE_STARTALIGN flag when we
> actually allocate the resource (so that we don't use the "start" field as
> alignment incorrectly when it no longer indicates alignment).
>
> That wouldn't be totally generic, but it would have the nice property of
> automatically at least add sanity checking for that whole "res->start has
> the odd meaning of 'alignment' during probing" and remove the need for a
> new field, and it would allow us to have a generic "resource_alignment()"
> routine that just gets a resource pointer.

Besides, I removed IORESOURCE_BUS_HAS_VGA flag which was unused for ages.

Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Gary Hade <garyhade@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

5 files changed, 51 insertions, 22 deletions

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index c2e99fd87faf..33d9b8bea6e0 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -235,7 +235,7 @@ static void pci_read_bases(struct pci_dev *dev, unsigned int howmany, int rom)
                         res->flags |= l & ~PCI_BASE_ADDRESS_IO_MASK;
                 }
                 res->end = res->start + (unsigned long) sz;
-                res->flags |= pci_calc_resource_flags(l);
+                res->flags |= pci_calc_resource_flags(l) | IORESOURCE_SIZEALIGN;
                 if (is_64bit_memory(l)) {
                         u32 szhi, lhi;
 
@@ -288,7 +288,8 @@ static void pci_read_bases(struct pci_dev *dev, unsigned int howmany, int rom)
                         if (sz) {
                                 res->flags = (l & IORESOURCE_ROM_ENABLE) |
                                   IORESOURCE_MEM | IORESOURCE_PREFETCH |
-                                  IORESOURCE_READONLY | IORESOURCE_CACHEABLE;
+                                  IORESOURCE_READONLY | IORESOURCE_CACHEABLE |
+                                  IORESOURCE_SIZEALIGN;
                                 res->start = l & PCI_ROM_ADDRESS_MASK;
                                 res->end = res->start + (unsigned long) sz;
                         }
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index f7cb8e0758b4..5cf84568c9e4 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -65,6 +65,7 @@ static void pbus_assign_resources_sorted(struct pci_bus *bus)
                 res = list->res;
                 idx = res - &list->dev->resource[0];
                 if (pci_assign_resource(list->dev, idx)) {
+                        /* FIXME: get rid of this */
                         res->start = 0;
                         res->end = 0;
                         res->flags = 0;
@@ -327,6 +328,7 @@ static void pbus_size_io(struct pci_bus *bus)
         /* Alignment of the IO window is always 4K */
         b_res->start = 4096;
         b_res->end = b_res->start + size - 1;
+        b_res->flags |= IORESOURCE_STARTALIGN;
 }
 
 /* Calculate the size of the bus and minimal alignment which
@@ -401,6 +403,7 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, unsigned long
         }
         b_res->start = min_align;
         b_res->end = size + min_align - 1;
+        b_res->flags |= IORESOURCE_STARTALIGN;
         return 1;
 }
 
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index bad509e40fbc..7d35cdf4579f 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -137,10 +137,16 @@ int pci_assign_resource(struct pci_dev *dev, int resno)
 
         size = res->end - res->start + 1;
         min = (res->flags & IORESOURCE_IO) ? PCIBIOS_MIN_IO : PCIBIOS_MIN_MEM;
-        /* The bridge resources are special, as their
-           size != alignment. Sizing routines return
-           required alignment in the "start" field. */
-        align = (resno < PCI_BRIDGE_RESOURCES) ? size : res->start;
+
+        align = resource_alignment(res);
+        if (!align) {
+                printk(KERN_ERR "PCI: Cannot allocate resource (bogus "
+                        "alignment) %d [%llx:%llx] (flags %lx) of %s\n",
+                        resno, (unsigned long long)res->start,
+                        (unsigned long long)res->end, res->flags,
+                        pci_name(dev));
+                return -EINVAL;
+        }
 
         /* First, try exact prefetching match.. */
         ret = pci_bus_alloc_resource(bus, res, size, align, min,
@@ -164,8 +170,10 @@ int pci_assign_resource(struct pci_dev *dev, int resno)
                         res->flags & IORESOURCE_IO ? "I/O" : "mem",
                         resno, (unsigned long long)size,
                         (unsigned long long)res->start, pci_name(dev));
-        } else if (resno < PCI_BRIDGE_RESOURCES) {
-                pci_update_resource(dev, res, resno);
+        } else {
+                res->flags &= ~IORESOURCE_STARTALIGN;
+                if (resno < PCI_BRIDGE_RESOURCES)
+                        pci_update_resource(dev, res, resno);
         }
 
         return ret;
@@ -226,29 +234,25 @@ void pdev_sort_resources(struct pci_dev *dev, struct resource_list *head)
                 if (r->flags & IORESOURCE_PCI_FIXED)
                         continue;
 
-                r_align = r->end - r->start;
-                
                 if (!(r->flags) || r->parent)
                         continue;
+
+                r_align = resource_alignment(r);
                 if (!r_align) {
-                        printk(KERN_WARNING "PCI: Ignore bogus resource %d "
-                                "[%llx:%llx] of %s\n",
+                        printk(KERN_WARNING "PCI: bogus alignment of resource "
+                                "%d [%llx:%llx] (flags %lx) of %s\n",
                                 i, (unsigned long long)r->start,
-                                (unsigned long long)r->end, pci_name(dev));
+                                (unsigned long long)r->end, r->flags,
+                                pci_name(dev));
                         continue;
                 }
-                r_align = (i < PCI_BRIDGE_RESOURCES) ? r_align + 1 : r->start;
                 for (list = head; ; list = list->next) {
                         resource_size_t align = 0;
                         struct resource_list *ln = list->next;
-                        int idx;
 
-                        if (ln) {
-                                idx = ln->res - &ln->dev->resource[0];
-                                align = (idx < PCI_BRIDGE_RESOURCES) ?
-                                        ln->res->end - ln->res->start + 1 :
-                                        ln->res->start;
-                        }
+                        if (ln)
+                                align = resource_alignment(ln->res);
+
                         if (r_align > align) {
                                 tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
                                 if (!tmp)
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 605d237364d2..d5d40a9f7929 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -44,7 +44,9 @@ struct resource_list {
 #define IORESOURCE_CACHEABLE    0x00004000
 #define IORESOURCE_RANGELENGTH  0x00008000
 #define IORESOURCE_SHADOWABLE   0x00010000
-#define IORESOURCE_BUS_HAS_VGA  0x00080000
+
+#define IORESOURCE_SIZEALIGN    0x00020000      /* size indicates alignment */
+#define IORESOURCE_STARTALIGN   0x00040000      /* start field is alignment */
 
 #define IORESOURCE_DISABLED     0x10000000
 #define IORESOURCE_UNSET        0x20000000
@@ -110,6 +112,7 @@ extern int allocate_resource(struct resource *root, struct resource *new,
                              void *alignf_data);
 int adjust_resource(struct resource *res, resource_size_t start,
                     resource_size_t size);
+resource_size_t resource_alignment(struct resource *res);
 
 /* Convenience shorthand with allocation */
 #define request_region(start,n,name)    __request_region(&ioport_resource, (start), (n), (name))
diff --git a/kernel/resource.c b/kernel/resource.c
index 82aea814d409..cee12cc47cab 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -486,6 +486,24 @@ int adjust_resource(struct resource *res, resource_size_t start, resource_size_t
 
 EXPORT_SYMBOL(adjust_resource);
 
+/**
+ * resource_alignment - calculate resource's alignment
+ * @res: resource pointer
+ *
+ * Returns alignment on success, 0 (invalid alignment) on failure.
+ */
+resource_size_t resource_alignment(struct resource *res)
+{
+        switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
+        case IORESOURCE_SIZEALIGN:
+                return res->end - res->start + 1;
+        case IORESOURCE_STARTALIGN:
+                return res->start;
+        default:
+                return 0;
+        }
+}
+
 /*
  * This is compatibility stuff for IO resources.
  *