xtensa: nommu support

Add support for !CONFIG_MMU setups.

Signed-off-by: Johannes Weiner <jw@emlix.com>
Signed-off-by: Chris Zankel <chris@zankel.net>

10 files changed, 77 insertions, 11 deletions

diff --git a/arch/xtensa/include/asm/cacheflush.h b/arch/xtensa/include/asm/cacheflush.h
index 94c4c53a099e..8fc1c0c8de07 100644
--- a/arch/xtensa/include/asm/cacheflush.h
+++ b/arch/xtensa/include/asm/cacheflush.h
@@ -65,13 +65,17 @@ extern void __flush_invalidate_dcache_range(unsigned long, unsigned long);
 # define __flush_invalidate_dcache_range(p,s)   __invalidate_dcache_range(p,s)
 #endif
 
-#if (DCACHE_WAY_SIZE > PAGE_SIZE)
+#if defined(CONFIG_MMU) && (DCACHE_WAY_SIZE > PAGE_SIZE)
 extern void __flush_invalidate_dcache_page_alias(unsigned long, unsigned long);
+#else
+static inline void __flush_invalidate_dcache_page_alias(unsigned long virt,
+                                                        unsigned long phys) { }
 #endif
-#if (ICACHE_WAY_SIZE > PAGE_SIZE)
+#if defined(CONFIG_MMU) && (ICACHE_WAY_SIZE > PAGE_SIZE)
 extern void __invalidate_icache_page_alias(unsigned long, unsigned long);
 #else
-# define __invalidate_icache_page_alias(v,p)    do { } while(0)
+static inline void __invalidate_icache_page_alias(unsigned long virt,
+                                                unsigned long phys) { }
 #endif
 
 /*
diff --git a/arch/xtensa/include/asm/dma.h b/arch/xtensa/include/asm/dma.h
index e30f3abf48f0..137ca3945b07 100644
--- a/arch/xtensa/include/asm/dma.h
+++ b/arch/xtensa/include/asm/dma.h
@@ -44,8 +44,9 @@
  *      the value desired).
  */
 
+#ifndef MAX_DMA_ADDRESS
 #define MAX_DMA_ADDRESS         (PAGE_OFFSET + XCHAL_KIO_SIZE - 1)
-
+#endif
 
 /* Reserve and release a DMA channel */
 extern int request_dma(unsigned int dmanr, const char * device_id);
diff --git a/arch/xtensa/include/asm/io.h b/arch/xtensa/include/asm/io.h
index 07b7299dab20..d04cd3a625fa 100644
--- a/arch/xtensa/include/asm/io.h
+++ b/arch/xtensa/include/asm/io.h
@@ -69,21 +69,28 @@ static inline void * phys_to_virt(unsigned long address)
 
 static inline void *ioremap(unsigned long offset, unsigned long size)
 {
+#ifdef CONFIG_MMU
         if (offset >= XCHAL_KIO_PADDR
             && offset < XCHAL_KIO_PADDR + XCHAL_KIO_SIZE)
                 return (void*)(offset-XCHAL_KIO_PADDR+XCHAL_KIO_BYPASS_VADDR);
-
         else
                 BUG();
+#else
+        return (void *)offset;
+#endif
 }
 
 static inline void *ioremap_nocache(unsigned long offset, unsigned long size)
 {
+#ifdef CONFIG_MMU
         if (offset >= XCHAL_KIO_PADDR
             && offset < XCHAL_KIO_PADDR + XCHAL_KIO_SIZE)
                 return (void*)(offset-XCHAL_KIO_PADDR+XCHAL_KIO_CACHED_VADDR);
         else
                 BUG();
+#else
+        return (void *)offset;
+#endif
 }
 
 static inline void iounmap(void *addr)
diff --git a/arch/xtensa/include/asm/mmu.h b/arch/xtensa/include/asm/mmu.h
index 44c5bb04c55c..04890d6e2335 100644
--- a/arch/xtensa/include/asm/mmu.h
+++ b/arch/xtensa/include/asm/mmu.h
@@ -11,7 +11,12 @@
 #ifndef _XTENSA_MMU_H
 #define _XTENSA_MMU_H
 
+#ifndef CONFIG_MMU
+#include <asm/nommu.h>
+#else
+
 /* Default "unsigned long" context */
 typedef unsigned long mm_context_t;
 
+#endif /* CONFIG_MMU */
 #endif  /* _XTENSA_MMU_H */
diff --git a/arch/xtensa/include/asm/mmu_context.h b/arch/xtensa/include/asm/mmu_context.h
index 6b7c19c8f4ce..dbd8731a876a 100644
--- a/arch/xtensa/include/asm/mmu_context.h
+++ b/arch/xtensa/include/asm/mmu_context.h
@@ -13,6 +13,10 @@
 #ifndef _XTENSA_MMU_CONTEXT_H
 #define _XTENSA_MMU_CONTEXT_H
 
+#ifndef CONFIG_MMU
+#include <asm/nommu_context.h>
+#else
+
 #include <linux/stringify.h>
 #include <linux/sched.h>
 
@@ -133,4 +137,5 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
 
 }
 
+#endif /* CONFIG_MMU */
 #endif /* _XTENSA_MMU_CONTEXT_H */
diff --git a/arch/xtensa/include/asm/nommu.h b/arch/xtensa/include/asm/nommu.h
new file mode 100644
index 000000000000..dce2c438c5ba
--- /dev/null
+++ b/arch/xtensa/include/asm/nommu.h
@@ -0,0 +1,3 @@
+typedef struct {
+        unsigned long end_brk;
+} mm_context_t;
diff --git a/arch/xtensa/include/asm/nommu_context.h b/arch/xtensa/include/asm/nommu_context.h
new file mode 100644
index 000000000000..599e7a2e729d
--- /dev/null
+++ b/arch/xtensa/include/asm/nommu_context.h
@@ -0,0 +1,25 @@
+static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
+{
+}
+
+static inline int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+{
+        return 0;
+}
+
+static inline void destroy_context(struct mm_struct *mm)
+{
+}
+
+static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
+{
+}
+
+static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
+                                struct task_struct *tsk)
+{
+}
+
+static inline void deactivate_mm(struct task_struct *tsk, struct mm_struct *mm)
+{
+}
diff --git a/arch/xtensa/include/asm/page.h b/arch/xtensa/include/asm/page.h
index a5a5d33c15d0..17e0c5383b10 100644
--- a/arch/xtensa/include/asm/page.h
+++ b/arch/xtensa/include/asm/page.h
@@ -33,8 +33,14 @@
 #define PAGE_SIZE               (__XTENSA_UL_CONST(1) << PAGE_SHIFT)
 #define PAGE_MASK               (~(PAGE_SIZE-1))
 
+#ifdef CONFIG_MMU
 #define PAGE_OFFSET             XCHAL_KSEG_CACHED_VADDR
 #define MAX_MEM_PFN             XCHAL_KSEG_SIZE
+#else
+#define PAGE_OFFSET             0
+#define MAX_MEM_PFN             (PLATFORM_DEFAULT_MEM_START + PLATFORM_DEFAULT_MEM_SIZE)
+#endif
+
 #define PGTABLE_START           0x80000000
 
 /*
@@ -165,8 +171,9 @@ extern void copy_user_page(void*, void*, unsigned long, struct page*);
 #define virt_addr_valid(kaddr)  pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
 #define page_to_phys(page)      (page_to_pfn(page) << PAGE_SHIFT)
 
+#ifdef CONFIG_MMU
 #define WANT_PAGE_VIRTUAL
-
+#endif
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/arch/xtensa/include/asm/pgtable.h b/arch/xtensa/include/asm/pgtable.h
index 8014d96b21f1..a138770c358e 100644
--- a/arch/xtensa/include/asm/pgtable.h
+++ b/arch/xtensa/include/asm/pgtable.h
@@ -183,7 +183,15 @@ extern unsigned long empty_zero_page[1024];
 
 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
 
+#ifdef CONFIG_MMU
 extern pgd_t swapper_pg_dir[PAGE_SIZE/sizeof(pgd_t)];
+extern void paging_init(void);
+extern void pgtable_cache_init(void);
+#else
+# define swapper_pg_dir NULL
+static inline void paging_init(void) { }
+static inline void pgtable_cache_init(void) { }
+#endif
 
 /*
  * The pmd contains the kernel virtual address of the pte page.
@@ -383,8 +391,6 @@ ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 
 #else
 
-extern void paging_init(void);
-
 #define kern_addr_valid(addr)   (1)
 
 extern  void update_mmu_cache(struct vm_area_struct * vma,
@@ -398,9 +404,6 @@ extern  void update_mmu_cache(struct vm_area_struct * vma,
 #define io_remap_pfn_range(vma,from,pfn,size,prot) \
                 remap_pfn_range(vma, from, pfn, size, prot)
 
-
-extern void pgtable_cache_init(void);
-
 typedef pte_t *pte_addr_t;
 
 #endif /* !defined (__ASSEMBLY__) */
diff --git a/arch/xtensa/include/asm/processor.h b/arch/xtensa/include/asm/processor.h
index fba8b7e44a22..0ea4937c0b61 100644
--- a/arch/xtensa/include/asm/processor.h
+++ b/arch/xtensa/include/asm/processor.h
@@ -13,6 +13,7 @@
 
 #include <variant/core.h>
 #include <asm/coprocessor.h>
+#include <platform/hardware.h>
 
 #include <linux/compiler.h>
 #include <asm/ptrace.h>
@@ -35,7 +36,12 @@
  * the 1 GB requirement applies to the stack as well.
  */
 
+#ifdef CONFIG_MMU
 #define TASK_SIZE       __XTENSA_UL_CONST(0x40000000)
+#else
+#define TASK_SIZE       (PLATFORM_DEFAULT_MEM_START + PLATFORM_DEFAULT_MEM_SIZE)
+#endif
+
 #define STACK_TOP       TASK_SIZE
 #define STACK_TOP_MAX   STACK_TOP