[IA64] more robust zx1/sx1000 machvec support

Machine vector selection has always been a bit of a hack given how
early in system boot it needs to be done.  Services like ACPI namespace
are not available and there are non-trivial problems to moving them to
early boot.  However, there's no reason we can't change to a different
machvec later in boot when the services we need are available.  By
adding a entry point for later initialization of the swiotlb, we can add
an error path for the hpzx1 machevec initialization and fall back to the
DIG machine vector if IOMMU hardware isn't found in the system.  Since
ia64 uses 4GB for zone DMA (no ISA support), it's trivial to allocate a
contiguous range from the slab for bounce buffer usage.

Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 32 insertions, 13 deletions

diff --git a/arch/ia64/hp/common/sba_iommu.c b/arch/ia64/hp/common/sba_iommu.c
index 11957598a8b9..e64ca04ace89 100644
--- a/arch/ia64/hp/common/sba_iommu.c
+++ b/arch/ia64/hp/common/sba_iommu.c
@@ -2028,9 +2028,40 @@ static struct acpi_driver acpi_sba_ioc_driver = {
 static int __init
 sba_init(void)
 {
+        if (!ia64_platform_is("hpzx1") && !ia64_platform_is("hpzx1_swiotlb"))
+                return 0;
+
         acpi_bus_register_driver(&acpi_sba_ioc_driver);
-        if (!ioc_list)
+        if (!ioc_list) {
+#ifdef CONFIG_IA64_GENERIC
+                extern int swiotlb_late_init_with_default_size (size_t size);
+
+                /*
+                 * If we didn't find something sba_iommu can claim, we
+                 * need to setup the swiotlb and switch to the dig machvec.
+                 */
+                if (swiotlb_late_init_with_default_size(64 * (1<<20)) != 0)
+                        panic("Unable to find SBA IOMMU or initialize "
+                              "software I/O TLB: Try machvec=dig boot option");
+                machvec_init("dig");
+#else
+                panic("Unable to find SBA IOMMU: Try a generic or DIG kernel");
+#endif
                 return 0;
+        }
+
+#if defined(CONFIG_IA64_GENERIC) || defined(CONFIG_IA64_HP_ZX1_SWIOTLB)
+        /*
+         * hpzx1_swiotlb needs to have a fairly small swiotlb bounce
+         * buffer setup to support devices with smaller DMA masks than
+         * sba_iommu can handle.
+         */
+        if (ia64_platform_is("hpzx1_swiotlb")) {
+                extern void hwsw_init(void);
+
+                hwsw_init();
+        }
+#endif
 
 #ifdef CONFIG_PCI
         {
@@ -2048,18 +2079,6 @@ sba_init(void)
 
 subsys_initcall(sba_init); /* must be initialized after ACPI etc., but before any drivers... */
 
-extern void dig_setup(char**);
-/*
- * MAX_DMA_ADDRESS needs to be setup prior to paging_init to do any good,
- * so we use the platform_setup hook to fix it up.
- */
-void __init
-sba_setup(char **cmdline_p)
-{
-        MAX_DMA_ADDRESS = ~0UL;
-        dig_setup(cmdline_p);
-}
-
 static int __init
 nosbagart(char *str)
 {