[POWERPC] Allow for different IOMMU page sizes in cell IOMMU code

Make some preliminary changes to cell_iommu_alloc_ptab() to allow it to
take the page size as a parameter rather than assuming IOMMU_PAGE_SIZE.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 18 insertions, 13 deletions

diff --git a/arch/powerpc/platforms/cell/iommu.c b/arch/powerpc/platforms/cell/iommu.c
index 7a861cb960d2..b0e347e4933a 100644
--- a/arch/powerpc/platforms/cell/iommu.c
+++ b/arch/powerpc/platforms/cell/iommu.c
@@ -113,7 +113,7 @@
 
 /* IOMMU sizing */
 #define IO_SEGMENT_SHIFT        28
-#define IO_PAGENO_BITS          (IO_SEGMENT_SHIFT - IOMMU_PAGE_SHIFT)
+#define IO_PAGENO_BITS(shift)   (IO_SEGMENT_SHIFT - (shift))
 
 /* The high bit needs to be set on every DMA address */
 #define SPIDER_DMA_OFFSET       0x80000000ul
@@ -328,7 +328,7 @@ static void cell_iommu_setup_stab(struct cbe_iommu *iommu,
 
 static unsigned long *cell_iommu_alloc_ptab(struct cbe_iommu *iommu,
                 unsigned long base, unsigned long size, unsigned long gap_base,
-                unsigned long gap_size)
+                unsigned long gap_size, unsigned long page_shift)
 {
         struct page *page;
         int i;
@@ -337,7 +337,10 @@ static unsigned long *cell_iommu_alloc_ptab(struct cbe_iommu *iommu,
 
         start_seg = base >> IO_SEGMENT_SHIFT;
         segments  = size >> IO_SEGMENT_SHIFT;
-        pages_per_segment = 1ull << IO_PAGENO_BITS;
+        pages_per_segment = 1ull << IO_PAGENO_BITS(page_shift);
+        /* PTEs for each segment must start on a 4K bounday */
+        pages_per_segment = max(pages_per_segment,
+                                (1 << 12) / sizeof(unsigned long));
 
         ptab_size = segments * pages_per_segment * sizeof(unsigned long);
         pr_debug("%s: iommu[%d]: ptab_size: %lu, order: %d\n", __FUNCTION__,
@@ -358,13 +361,12 @@ static unsigned long *cell_iommu_alloc_ptab(struct cbe_iommu *iommu,
         /* initialise the STEs */
         reg = IOSTE_V | ((n_pte_pages - 1) << 5);
 
-        if (IOMMU_PAGE_SIZE == 0x1000)
-                reg |= IOSTE_PS_4K;
-        else if (IOMMU_PAGE_SIZE == 0x10000)
-                reg |= IOSTE_PS_64K;
-        else {
-                extern void __unknown_page_size_error(void);
-                __unknown_page_size_error();
+        switch (page_shift) {
+        case 12: reg |= IOSTE_PS_4K;  break;
+        case 16: reg |= IOSTE_PS_64K; break;
+        case 20: reg |= IOSTE_PS_1M;  break;
+        case 24: reg |= IOSTE_PS_16M; break;
+        default: BUG();
         }
 
         gap_base = gap_base >> IO_SEGMENT_SHIFT;
@@ -429,7 +431,8 @@ static void cell_iommu_setup_hardware(struct cbe_iommu *iommu,
         unsigned long base, unsigned long size)
 {
         cell_iommu_setup_stab(iommu, base, size, 0, 0);
-        iommu->ptab = cell_iommu_alloc_ptab(iommu, base, size, 0, 0);
+        iommu->ptab = cell_iommu_alloc_ptab(iommu, base, size, 0, 0,
+                                            IOMMU_PAGE_SHIFT);
         cell_iommu_enable_hardware(iommu);
 }
 
@@ -886,7 +889,8 @@ static void cell_iommu_setup_fixed_ptab(struct cbe_iommu *iommu,
         int i;
         unsigned long base_pte, uaddr, *io_pte, *ptab;
 
-        ptab = cell_iommu_alloc_ptab(iommu, fbase, fsize, dbase, dsize);
+        ptab = cell_iommu_alloc_ptab(iommu, fbase, fsize, dbase, dsize,
+                                     IOMMU_PAGE_SHIFT);
 
         dma_iommu_fixed_base = fbase;
 
@@ -1008,7 +1012,8 @@ static int __init cell_iommu_fixed_mapping_init(void)
                          dbase + dsize, fbase, fbase + fsize);
 
                 cell_iommu_setup_stab(iommu, dbase, dsize, fbase, fsize);
-                iommu->ptab = cell_iommu_alloc_ptab(iommu, dbase, dsize, 0, 0);
+                iommu->ptab = cell_iommu_alloc_ptab(iommu, dbase, dsize, 0, 0,
+                                                    IOMMU_PAGE_SHIFT);
                 cell_iommu_setup_fixed_ptab(iommu, np, dbase, dsize,
                                              fbase, fsize);
                 cell_iommu_enable_hardware(iommu);