tilegx pci: support I/O to arbitrarily-cached pages

The tilegx PCI root complex support (currently only in linux-next)
is limited to pages that are homed on cached in the default manner,
i.e. "hash-for-home".  This change supports delivery of I/O data to
pages that are cached in other ways (locally on a particular core,
uncached, user-managed incoherent, etc.).

A large part of the change is supporting flushing pages from cache
on particular homes so that we can transition the data that we are
delivering to or from the device appropriately.  The new homecache_finv*
routines handle this.

Some changes to page_table_range_init() were also required to make
the fixmap code work correctly on tilegx; it hadn't been used there
before.

We also remove some stub mark_caches_evicted_*() routines that
were just no-ops anyway.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

1 files changed, 24 insertions, 35 deletions

diff --git a/arch/tile/mm/init.c b/arch/tile/mm/init.c
index 630dd2ce2afe..a2417a0a8222 100644
--- a/arch/tile/mm/init.c
+++ b/arch/tile/mm/init.c
@@ -150,7 +150,21 @@ void __init shatter_pmd(pmd_t *pmd)
 	assign_pte(pmd, pte);
 }
 
-#ifdef CONFIG_HIGHMEM
+#ifdef __tilegx__
+static pmd_t *__init get_pmd(pgd_t pgtables[], unsigned long va)
+{
+	pud_t *pud = pud_offset(&pgtables[pgd_index(va)], va);
+	if (pud_none(*pud))
+		assign_pmd(pud, alloc_pmd());
+	return pmd_offset(pud, va);
+}
+#else
+static pmd_t *__init get_pmd(pgd_t pgtables[], unsigned long va)
+{
+	return pmd_offset(pud_offset(&pgtables[pgd_index(va)], va), va);
+}
+#endif
+
 /*
  * This function initializes a certain range of kernel virtual memory
  * with new bootmem page tables, everywhere page tables are missing in
@@ -163,24 +177,17 @@ void __init shatter_pmd(pmd_t *pmd)
  * checking the pgd every time.
  */
 static void __init page_table_range_init(unsigned long start,
-					 unsigned long end, pgd_t *pgd_base)
+					 unsigned long end, pgd_t *pgd)
 {
-	pgd_t *pgd;
-	int pgd_idx;
 	unsigned long vaddr;
-
-	vaddr = start;
-	pgd_idx = pgd_index(vaddr);
-	pgd = pgd_base + pgd_idx;
-
-	for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
-		pmd_t *pmd = pmd_offset(pud_offset(pgd, vaddr), vaddr);
+	start = round_down(start, PMD_SIZE);
+	end = round_up(end, PMD_SIZE);
+	for (vaddr = start; vaddr < end; vaddr += PMD_SIZE) {
+		pmd_t *pmd = get_pmd(pgd, vaddr);
 		if (pmd_none(*pmd))
 			assign_pte(pmd, alloc_pte());
-		vaddr += PMD_SIZE;
 	}
 }
-#endif /* CONFIG_HIGHMEM */
 
 
 #if CHIP_HAS_CBOX_HOME_MAP()
@@ -404,21 +411,6 @@ static inline pgprot_t ktext_set_nocache(pgprot_t prot)
 	return prot;
 }
 
-#ifndef __tilegx__
-static pmd_t *__init get_pmd(pgd_t pgtables[], unsigned long va)
-{
-	return pmd_offset(pud_offset(&pgtables[pgd_index(va)], va), va);
-}
-#else
-static pmd_t *__init get_pmd(pgd_t pgtables[], unsigned long va)
-{
-	pud_t *pud = pud_offset(&pgtables[pgd_index(va)], va);
-	if (pud_none(*pud))
-		assign_pmd(pud, alloc_pmd());
-	return pmd_offset(pud, va);
-}
-#endif
-
 /* Temporary page table we use for staging. */
 static pgd_t pgtables[PTRS_PER_PGD]
  __attribute__((aligned(HV_PAGE_TABLE_ALIGN)));
@@ -779,9 +771,6 @@ static void __init set_non_bootmem_pages_init(void)
  */
 void __init paging_init(void)
 {
-#ifdef CONFIG_HIGHMEM
-	unsigned long vaddr, end;
-#endif
 #ifdef __tilegx__
 	pud_t *pud;
 #endif
@@ -789,14 +778,14 @@ void __init paging_init(void)
 
 	kernel_physical_mapping_init(pgd_base);
 
-#ifdef CONFIG_HIGHMEM
 	/*
 	 * Fixed mappings, only the page table structure has to be
 	 * created - mappings will be set by set_fixmap():
 	 */
-	vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
-	end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
-	page_table_range_init(vaddr, end, pgd_base);
+	page_table_range_init(fix_to_virt(__end_of_fixed_addresses - 1),
+			      FIXADDR_TOP, pgd_base);
+
+#ifdef CONFIG_HIGHMEM
 	permanent_kmaps_init(pgd_base);
 #endif