[PARISC] Truncate overlapping PAT PDC reported ranges

Deal with overlapping LBA MMIO resources,

rp3440 PDC BUG: PDC reports lmmio range for the last rope that overlaps
with the CPU HPA. Console output was:

...
Found devices:
1. Storm Peak Fast at 0xfffffffffe798000 [152] { 0, 0x0, 0x889, 0x00004 }
2. Storm Peak Fast at 0xfffffffffe799000 [153] { 0, 0x0, 0x889, 0x00004 }
...
FAILED: lba_fixup_bus() request for lmmio_space
[fffffffff0000000/fffffffffecffffe]

Output is now:

LBA: Truncating lmmio_space [fffffffff0000000/fffffffffecffffe] to
[fffffffff0000000,fffffffffe797fff]

My only concern with this patch is how C8000 (PAT PDC) will report
elmmio ranges when a gfx card is installed. I'll have to test this
another day.

Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
Signed-off-by: James Bottomley <jejb@parisc-linux.org>
Signed-off-by: Matthew Wilcox <willy@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>

diff --git a/drivers/parisc/lba_pci.c b/drivers/parisc/lba_pci.c
index 4f6bdf0..cbae8c8 100644 (file)
--- a/drivers/parisc/lba_pci.c
+++ b/drivers/parisc/lba_pci.c
@@ -695,11 +695,71 @@ lba_claim_dev_resources(struct pci_dev *dev)
                }
        }
 }
+
+
+/*
+ * truncate_pat_collision:  Deal with overlaps or outright collisions
+ *                     between PAT PDC reported ranges.
+ *
+ *   Broken PA8800 firmware will report lmmio range that
+ *   overlaps with CPU HPA. Just truncate the lmmio range.
+ *
+ *   BEWARE: conflicts with this lmmio range may be an
+ *   elmmio range which is pointing down another rope.
+ *
+ *  FIXME: only deals with one collision per range...theoretically we
+ *  could have several. Supporting more than one collision will get messy.
+ */
+static unsigned long
+truncate_pat_collision(struct resource *root, struct resource *new)
+{
+       unsigned long start = new->start;
+       unsigned long end = new->end;
+       struct resource *tmp = root->child;
+
+       if (end <= start || start < root->start || !tmp)
+               return 0;
+
+       /* find first overlap */
+       while (tmp && tmp->end < start)
+               tmp = tmp->sibling;
+
+       /* no entries overlap */
+       if (!tmp)  return 0;
+
+       /* found one that starts behind the new one
+       ** Don't need to do anything.
+       */
+       if (tmp->start >= end) return 0;
+
+       if (tmp->start <= start) {
+               /* "front" of new one overlaps */
+               new->start = tmp->end + 1;
+
+               if (tmp->end >= end) {
+                       /* AACCKK! totally overlaps! drop this range. */
+                       return 1;
+               }
+       } 
+
+       if (tmp->end < end ) {
+               /* "end" of new one overlaps */
+               new->end = tmp->start - 1;
+       }
+
+       printk(KERN_WARNING "LBA: Truncating lmmio_space [%lx/%lx] "
+                                       "to [%lx,%lx]\n",
+                       start, end,
+                       new->start, new->end );
+
+       return 0;       /* truncation successful */
+}
+
 #else
-#define lba_claim_dev_resources(dev)
+#define lba_claim_dev_resources(dev) do { } while (0)
+#define truncate_pat_collision(r,n)  (0)
 #endif
 
-
 /*
 ** The algorithm is generic code.
 ** But it needs to access local data structures to get the IRQ base.
@@ -747,6 +807,9 @@ lba_fixup_bus(struct pci_bus *bus)
                        lba_dump_res(&ioport_resource, 2);
                        BUG();
                }
+               /* advertize Host bridge resources to PCI bus */
+               bus->resource[0] = &(ldev->hba.io_space);
+               i = 1;
 
                if (ldev->hba.elmmio_space.start) {
                        err = request_resource(&iomem_resource,
@@ -760,23 +823,35 @@ lba_fixup_bus(struct pci_bus *bus)
 
                                /* lba_dump_res(&iomem_resource, 2); */
                                /* BUG(); */
-                       }
+                       } else
+                               bus->resource[i++] = &(ldev->hba.elmmio_space);
                }
 
-               err = request_resource(&iomem_resource, &(ldev->hba.lmmio_space));
-               if (err < 0) {
-                       /*   FIXME  overlaps with elmmio will fail here.
-                        *   Need to prune (or disable) the distributed range.
-                        *
-                        *   BEWARE: conflicts with this lmmio range may be
-                        *   elmmio range which is pointing down another rope.
-                        */
-
-                       printk("FAILED: lba_fixup_bus() request for "
+
+               /*   Overlaps with elmmio can (and should) fail here.
+                *   We will prune (or ignore) the distributed range.
+                *
+                *   FIXME: SBA code should register all elmmio ranges first.
+                *      that would take care of elmmio ranges routed
+                *      to a different rope (already discovered) from
+                *      getting registered *after* LBA code has already
+                *      registered it's distributed lmmio range.
+                */
+               if (truncate_pat_collision(&iomem_resource,
+                                       &(ldev->hba.lmmio_space))) {
+
+                       printk(KERN_WARNING "LBA: lmmio_space [%lx/%lx] duplicate!\n",
+                                       ldev->hba.lmmio_space.start,
+                                       ldev->hba.lmmio_space.end);
+               } else {
+                       err = request_resource(&iomem_resource, &(ldev->hba.lmmio_space));
+                       if (err < 0) {
+                               printk(KERN_ERR "FAILED: lba_fixup_bus() request for "
                                        "lmmio_space [%lx/%lx]\n",
                                        ldev->hba.lmmio_space.start,
                                        ldev->hba.lmmio_space.end);
-                       /* lba_dump_res(&iomem_resource, 2); */
+                       } else
+                               bus->resource[i++] = &(ldev->hba.lmmio_space);
                }
 
 #ifdef CONFIG_64BIT
@@ -791,18 +866,10 @@ lba_fixup_bus(struct pci_bus *bus)
                                lba_dump_res(&iomem_resource, 2);
                                BUG();
                        }
+                       bus->resource[i++] = &(ldev->hba.gmmio_space);
                }
 #endif
 
-               /* advertize Host bridge resources to PCI bus */
-               bus->resource[0] = &(ldev->hba.io_space);
-               bus->resource[1] = &(ldev->hba.lmmio_space);
-               i=2;
-               if (ldev->hba.elmmio_space.start)
-                       bus->resource[i++] = &(ldev->hba.elmmio_space);
-               if (ldev->hba.gmmio_space.start)
-                       bus->resource[i++] = &(ldev->hba.gmmio_space);
-                       
        }
 
        list_for_each(ln, &bus->devices) {