Initial import

6 files changed, 762 insertions, 0 deletions

diff --git a/arch/cris/arch-v32/mm/Makefile b/arch/cris/arch-v32/mm/Makefile
new file mode 100644
index 000000000..0b801f296
--- /dev/null
+++ b/arch/cris/arch-v32/mm/Makefile
@@ -0,0 +1,4 @@
+# Makefile for the Linux/cris parts of the memory manager.
+
+obj-y	 += mmu.o init.o tlb.o intmem.o
+obj-$(CONFIG_ETRAX_L2CACHE)    += l2cache.o
diff --git a/arch/cris/arch-v32/mm/init.c b/arch/cris/arch-v32/mm/init.c
new file mode 100644
index 000000000..f5438ca81
--- /dev/null
+++ b/arch/cris/arch-v32/mm/init.c
@@ -0,0 +1,162 @@
+/*
+ * Set up paging and the MMU.
+ *
+ * Copyright (C) 2000-2003, Axis Communications AB.
+ *
+ * Authors:   Bjorn Wesen <bjornw@axis.com>
+ *            Tobias Anderberg <tobiasa@axis.com>, CRISv32 port.
+ */
+#include <linux/mmzone.h>
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/mm.h>
+#include <asm/pgtable.h>
+#include <asm/page.h>
+#include <asm/types.h>
+#include <asm/mmu.h>
+#include <asm/io.h>
+#include <asm/mmu_context.h>
+#include <arch/hwregs/asm/mmu_defs_asm.h>
+#include <arch/hwregs/supp_reg.h>
+
+extern void tlb_init(void);
+
+/*
+ * The kernel is already mapped with linear mapping at kseg_c so there's no
+ * need to map it with a page table. However, head.S also temporarily mapped it
+ * at kseg_4 thus the ksegs are set up again. Also clear the TLB and do various
+ * other paging stuff.
+ */
+void __init cris_mmu_init(void)
+{
+	unsigned long mmu_config;
+	unsigned long mmu_kbase_hi;
+	unsigned long mmu_kbase_lo;
+	unsigned short mmu_page_id;
+
+	/*
+	 * Make sure the current pgd table points to something sane, even if it
+	 * is most probably not used until the next switch_mm.
+	 */
+	per_cpu(current_pgd, smp_processor_id()) = init_mm.pgd;
+
+	/* Initialise the TLB. Function found in tlb.c. */
+	tlb_init();
+
+	/*
+	 * Enable exceptions and initialize the kernel segments.
+	 * See head.S for differences between ARTPEC-3 and ETRAX FS.
+	 */
+	mmu_config = ( REG_STATE(mmu, rw_mm_cfg, we, on)        |
+		       REG_STATE(mmu, rw_mm_cfg, acc, on)       |
+		       REG_STATE(mmu, rw_mm_cfg, ex, on)        |
+		       REG_STATE(mmu, rw_mm_cfg, inv, on)       |
+#ifdef CONFIG_CRIS_MACH_ARTPEC3
+		       REG_STATE(mmu, rw_mm_cfg, seg_f, page)   |
+		       REG_STATE(mmu, rw_mm_cfg, seg_e, page)   |
+		       REG_STATE(mmu, rw_mm_cfg, seg_d, linear) |
+#else
+		       REG_STATE(mmu, rw_mm_cfg, seg_f, linear) |
+		       REG_STATE(mmu, rw_mm_cfg, seg_e, linear) |
+		       REG_STATE(mmu, rw_mm_cfg, seg_d, page)   |
+#endif
+		       REG_STATE(mmu, rw_mm_cfg, seg_c, linear) |
+		       REG_STATE(mmu, rw_mm_cfg, seg_b, linear) |
+                       REG_STATE(mmu, rw_mm_cfg, seg_a, page)   |
+		       REG_STATE(mmu, rw_mm_cfg, seg_9, page)   |
+		       REG_STATE(mmu, rw_mm_cfg, seg_8, page)   |
+		       REG_STATE(mmu, rw_mm_cfg, seg_7, page)   |
+		       REG_STATE(mmu, rw_mm_cfg, seg_6, page)   |
+		       REG_STATE(mmu, rw_mm_cfg, seg_5, page)   |
+		       REG_STATE(mmu, rw_mm_cfg, seg_4, page)   |
+		       REG_STATE(mmu, rw_mm_cfg, seg_3, page)   |
+		       REG_STATE(mmu, rw_mm_cfg, seg_2, page)   |
+		       REG_STATE(mmu, rw_mm_cfg, seg_1, page)   |
+		       REG_STATE(mmu, rw_mm_cfg, seg_0, page));
+
+	/* See head.S for differences between ARTPEC-3 and ETRAX FS. */
+	mmu_kbase_hi = ( REG_FIELD(mmu, rw_mm_kbase_hi, base_f, 0x0) |
+#ifdef CONFIG_CRIS_MACH_ARTPEC3
+			 REG_FIELD(mmu, rw_mm_kbase_hi, base_e, 0x0) |
+			 REG_FIELD(mmu, rw_mm_kbase_hi, base_d, 0x5) |
+#else
+			 REG_FIELD(mmu, rw_mm_kbase_hi, base_e, 0x8) |
+			 REG_FIELD(mmu, rw_mm_kbase_hi, base_d, 0x0) |
+#endif
+                         REG_FIELD(mmu, rw_mm_kbase_hi, base_c, 0x4) |
+			 REG_FIELD(mmu, rw_mm_kbase_hi, base_b, 0xb) |
+			 REG_FIELD(mmu, rw_mm_kbase_hi, base_a, 0x0) |
+			 REG_FIELD(mmu, rw_mm_kbase_hi, base_9, 0x0) |
+			 REG_FIELD(mmu, rw_mm_kbase_hi, base_8, 0x0));
+
+	mmu_kbase_lo = ( REG_FIELD(mmu, rw_mm_kbase_lo, base_7, 0x0) |
+			 REG_FIELD(mmu, rw_mm_kbase_lo, base_6, 0x0) |
+			 REG_FIELD(mmu, rw_mm_kbase_lo, base_5, 0x0) |
+			 REG_FIELD(mmu, rw_mm_kbase_lo, base_4, 0x0) |
+			 REG_FIELD(mmu, rw_mm_kbase_lo, base_3, 0x0) |
+			 REG_FIELD(mmu, rw_mm_kbase_lo, base_2, 0x0) |
+			 REG_FIELD(mmu, rw_mm_kbase_lo, base_1, 0x0) |
+			 REG_FIELD(mmu, rw_mm_kbase_lo, base_0, 0x0));
+
+	mmu_page_id = REG_FIELD(mmu, rw_mm_tlb_hi, pid, 0);
+
+	/* Update the instruction MMU. */
+	SUPP_BANK_SEL(BANK_IM);
+	SUPP_REG_WR(RW_MM_CFG, mmu_config);
+	SUPP_REG_WR(RW_MM_KBASE_HI, mmu_kbase_hi);
+	SUPP_REG_WR(RW_MM_KBASE_LO, mmu_kbase_lo);
+	SUPP_REG_WR(RW_MM_TLB_HI, mmu_page_id);
+
+	/* Update the data MMU. */
+	SUPP_BANK_SEL(BANK_DM);
+	SUPP_REG_WR(RW_MM_CFG, mmu_config);
+	SUPP_REG_WR(RW_MM_KBASE_HI, mmu_kbase_hi);
+	SUPP_REG_WR(RW_MM_KBASE_LO, mmu_kbase_lo);
+	SUPP_REG_WR(RW_MM_TLB_HI, mmu_page_id);
+
+	SPEC_REG_WR(SPEC_REG_PID, 0);
+
+	/*
+	 * The MMU has been enabled ever since head.S but just to make it
+	 * totally obvious enable it here as well.
+	 */
+	SUPP_BANK_SEL(BANK_GC);
+	SUPP_REG_WR(RW_GC_CFG, 0xf); /* IMMU, DMMU, ICache, DCache on */
+}
+
+void __init paging_init(void)
+{
+	int i;
+	unsigned long zones_size[MAX_NR_ZONES];
+
+	printk("Setting up paging and the MMU.\n");
+
+	/* Clear out the init_mm.pgd that will contain the kernel's mappings. */
+	for(i = 0; i < PTRS_PER_PGD; i++)
+		swapper_pg_dir[i] = __pgd(0);
+
+	cris_mmu_init();
+
+	/*
+	 * Initialize the bad page table and bad page to point to a couple of
+	 * allocated pages.
+	 */
+	empty_zero_page = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
+	memset((void *) empty_zero_page, 0, PAGE_SIZE);
+
+	/* All pages are DMA'able in Etrax, so put all in the DMA'able zone. */
+	zones_size[0] = ((unsigned long) high_memory - PAGE_OFFSET) >> PAGE_SHIFT;
+
+	for (i = 1; i < MAX_NR_ZONES; i++)
+		zones_size[i] = 0;
+
+	/*
+	 * Use free_area_init_node instead of free_area_init, because it is
+	 * designed for systems where the DRAM starts at an address
+	 * substantially higher than 0, like us (we start at PAGE_OFFSET). This
+	 * saves space in the mem_map page array.
+	 */
+	free_area_init_node(0, zones_size, PAGE_OFFSET >> PAGE_SHIFT, 0);
+
+	mem_map = contig_page_data.node_mem_map;
+}
diff --git a/arch/cris/arch-v32/mm/intmem.c b/arch/cris/arch-v32/mm/intmem.c
new file mode 100644
index 000000000..1b17d92ce
--- /dev/null
+++ b/arch/cris/arch-v32/mm/intmem.c
@@ -0,0 +1,150 @@
+/*
+ * Simple allocator for internal RAM in ETRAX FS
+ *
+ * Copyright (c) 2004 Axis Communications AB.
+ */
+
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <asm/io.h>
+#include <memmap.h>
+
+#define STATUS_FREE 0
+#define STATUS_ALLOCATED 1
+
+#ifdef CONFIG_ETRAX_L2CACHE
+#define RESERVED_SIZE 66*1024
+#else
+#define RESERVED_SIZE 0
+#endif
+
+struct intmem_allocation {
+	struct list_head entry;
+	unsigned int size;
+	unsigned offset;
+	char status;
+};
+
+
+static struct list_head intmem_allocations;
+static void* intmem_virtual;
+
+static void crisv32_intmem_init(void)
+{
+	static int initiated = 0;
+	if (!initiated) {
+		struct intmem_allocation* alloc;
+		alloc = kmalloc(sizeof *alloc, GFP_KERNEL);
+		INIT_LIST_HEAD(&intmem_allocations);
+		intmem_virtual = ioremap(MEM_INTMEM_START + RESERVED_SIZE,
+					 MEM_INTMEM_SIZE - RESERVED_SIZE);
+		initiated = 1;
+		alloc->size = MEM_INTMEM_SIZE - RESERVED_SIZE;
+		alloc->offset = 0;
+		alloc->status = STATUS_FREE;
+		list_add_tail(&alloc->entry, &intmem_allocations);
+	}
+}
+
+void* crisv32_intmem_alloc(unsigned size, unsigned align)
+{
+	struct intmem_allocation* allocation;
+	struct intmem_allocation* tmp;
+	void* ret = NULL;
+
+	preempt_disable();
+	crisv32_intmem_init();
+
+	list_for_each_entry_safe(allocation, tmp, &intmem_allocations, entry) {
+		int alignment = allocation->offset % align;
+		alignment = alignment ? align - alignment : alignment;
+
+		if (allocation->status == STATUS_FREE &&
+		    allocation->size >= size + alignment) {
+			if (allocation->size > size + alignment) {
+				struct intmem_allocation* alloc;
+				alloc = kmalloc(sizeof *alloc, GFP_ATOMIC);
+				alloc->status = STATUS_FREE;
+				alloc->size = allocation->size - size -
+					alignment;
+				alloc->offset = allocation->offset + size +
+					alignment;
+				list_add(&alloc->entry, &allocation->entry);
+
+				if (alignment) {
+					struct intmem_allocation *tmp;
+					tmp = kmalloc(sizeof *tmp, GFP_ATOMIC);
+					tmp->offset = allocation->offset;
+					tmp->size = alignment;
+					tmp->status = STATUS_FREE;
+					allocation->offset += alignment;
+					list_add_tail(&tmp->entry,
+						&allocation->entry);
+				}
+			}
+			allocation->status = STATUS_ALLOCATED;
+			allocation->size = size;
+			ret = (void*)((int)intmem_virtual + allocation->offset);
+		}
+	}
+	preempt_enable();
+	return ret;
+}
+
+void crisv32_intmem_free(void* addr)
+{
+	struct intmem_allocation* allocation;
+	struct intmem_allocation* tmp;
+
+	if (addr == NULL)
+		return;
+
+	preempt_disable();
+	crisv32_intmem_init();
+
+	list_for_each_entry_safe(allocation, tmp, &intmem_allocations, entry) {
+		if (allocation->offset == (int)(addr - intmem_virtual)) {
+			struct intmem_allocation *prev =
+			  list_entry(allocation->entry.prev,
+			             struct intmem_allocation, entry);
+			struct intmem_allocation *next =
+			  list_entry(allocation->entry.next,
+				     struct intmem_allocation, entry);
+
+			allocation->status = STATUS_FREE;
+			/* Join with prev and/or next if also free */
+			if ((prev != &intmem_allocations) &&
+					(prev->status == STATUS_FREE)) {
+				prev->size += allocation->size;
+				list_del(&allocation->entry);
+				kfree(allocation);
+				allocation = prev;
+			}
+			if ((next != &intmem_allocations) &&
+					(next->status == STATUS_FREE)) {
+				allocation->size += next->size;
+				list_del(&next->entry);
+				kfree(next);
+			}
+			preempt_enable();
+			return;
+		}
+	}
+	preempt_enable();
+}
+
+void* crisv32_intmem_phys_to_virt(unsigned long addr)
+{
+	return (void *)(addr - (MEM_INTMEM_START + RESERVED_SIZE) +
+		(unsigned long)intmem_virtual);
+}
+
+unsigned long crisv32_intmem_virt_to_phys(void* addr)
+{
+	return (unsigned long)((unsigned long )addr -
+		(unsigned long)intmem_virtual + MEM_INTMEM_START +
+		RESERVED_SIZE);
+}
+
+module_init(crisv32_intmem_init);
+
diff --git a/arch/cris/arch-v32/mm/l2cache.c b/arch/cris/arch-v32/mm/l2cache.c
new file mode 100644
index 000000000..332ff10dc
--- /dev/null
+++ b/arch/cris/arch-v32/mm/l2cache.c
@@ -0,0 +1,29 @@
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <memmap.h>
+#include <hwregs/reg_map.h>
+#include <hwregs/reg_rdwr.h>
+#include <hwregs/l2cache_defs.h>
+#include <asm/io.h>
+
+#define L2CACHE_SIZE 64
+
+int __init l2cache_init(void)
+{
+	reg_l2cache_rw_ctrl ctrl = {0};
+	reg_l2cache_rw_cfg cfg = {.en = regk_l2cache_yes};
+
+	ctrl.csize = L2CACHE_SIZE;
+	ctrl.cbase = L2CACHE_SIZE / 4 + (L2CACHE_SIZE % 4 ? 1 : 0);
+	REG_WR(l2cache, regi_l2cache, rw_ctrl, ctrl);
+
+	/* Flush the tag memory */
+	memset((void *)(MEM_INTMEM_START | MEM_NON_CACHEABLE), 0, 2*1024);
+
+	/* Enable the cache */
+	REG_WR(l2cache, regi_l2cache, rw_cfg, cfg);
+
+	return 0;
+}
+
diff --git a/arch/cris/arch-v32/mm/mmu.S b/arch/cris/arch-v32/mm/mmu.S
new file mode 100644
index 000000000..c0981044e
--- /dev/null
+++ b/arch/cris/arch-v32/mm/mmu.S
@@ -0,0 +1,210 @@
+; WARNING : The refill handler has been modified, see below !!!
+
+/*
+ *  Copyright (C) 2003 Axis Communications AB
+ *
+ *  Authors:	Mikael Starvik (starvik@axis.com)
+ *
+ * Code for the fault low-level handling routines.
+ *
+ */
+
+#include <asm/page.h>
+#include <asm/pgtable.h>
+
+; Save all register. Must save in same order as struct pt_regs.
+.macro SAVE_ALL
+	subq	12, $sp
+	move	$erp, [$sp]
+	subq	4, $sp
+	move	$srp, [$sp]
+	subq	4, $sp
+	move	$ccs, [$sp]
+	subq	4, $sp
+	move	$spc, [$sp]
+	subq	4, $sp
+	move	$mof, [$sp]
+	subq	4, $sp
+	move	$srs, [$sp]
+	subq	4, $sp
+	move.d	$acr, [$sp]
+	subq	14*4, $sp
+	movem	$r13, [$sp]
+	subq	4, $sp
+	move.d	$r10, [$sp]
+.endm
+
+; Bus fault handler. Extracts relevant information and calls mm subsystem
+; to handle the fault.
+.macro	MMU_BUS_FAULT_HANDLER handler, mmu, we, ex
+	.globl	\handler
+	.type   \handler,"function"
+\handler:
+	SAVE_ALL
+	move	\mmu, $srs	; Select MMU support register bank
+	move.d  $sp, $r11	; regs
+	moveq	1, $r12		; protection fault
+	moveq   \we, $r13	; write exception?
+	orq	\ex << 1, $r13	; execute?
+	move    $s3, $r10	; rw_mm_cause
+	and.d	~8191, $r10	; Get faulting page start address
+
+	jsr	do_page_fault
+	nop
+	ba	ret_from_intr
+	nop
+	.size   \handler, . - \handler
+.endm
+
+; Refill handler. Three cases may occur:
+;   1. PMD and PTE exists in mm subsystem but not in TLB
+;   2. PMD exists but not PTE
+;   3. PMD doesn't exist
+; The code below handles case 1 and calls the mm subsystem for case 2 and 3.
+; Do not touch this code without very good reasons and extensive testing.
+; Note that the code is optimized to minimize stalls (makes the code harder
+; to read).
+;
+; WARNING !!!
+; Modified by Mikael Asker 060725: added a workaround for strange TLB
+; behavior. If the same PTE is present in more than one set, the TLB
+; doesn't recognize it and we get stuck in a loop of refill exceptions.
+; The workaround detects such loops and exits them by flushing
+; the TLB contents. The problem and workaround were verified
+; in VCS by Mikael Starvik.
+;
+; Each page is 8 KB. Each PMD holds 8192/4 PTEs (each PTE is 4 bytes) so each
+; PMD holds 16 MB of virtual memory.
+;   Bits  0-12 : Offset within a page
+;   Bits 13-23 : PTE offset within a PMD
+;   Bits 24-31 : PMD offset within the PGD
+
+.macro MMU_REFILL_HANDLER handler, mmu
+	.data
+1:	.dword	0		; refill_count
+                                ;   == 0 <=> last_refill_cause is invalid
+2:	.dword	0		; last_refill_cause
+	.text
+	.globl \handler
+	.type   \handler, "function"
+\handler:
+	subq	4, $sp
+; (The pipeline stalls for one cycle; $sp used as address in the next cycle.)
+	move	$srs, [$sp]
+	subq	4, $sp
+	move	\mmu, $srs	; Select MMU support register bank
+	move.d	$acr, [$sp]
+	subq	12, $sp
+	move.d	1b, $acr        ; Point to refill_count
+	movem	$r2, [$sp]
+
+	test.d	[$acr]	        ; refill_count == 0 ?
+	beq	5f		;   yes, last_refill_cause is invalid
+        move.d	$acr, $r1
+
+	; last_refill_cause is valid, investigate cause
+        addq    4, $r1          ; Point to last_refill_cause
+	move	$s3, $r0	; Get rw_mm_cause
+	move.d	[$r1], $r2	; Get last_refill_cause
+	cmp.d	$r0, $r2	; rw_mm_cause == last_refill_cause ?
+	beq	6f		;   yes, increment count
+	moveq	1, $r2
+
+        ; rw_mm_cause != last_refill_cause
+	move.d	$r2, [$acr]	; refill_count = 1
+	move.d	$r0, [$r1]	; last_refill_cause = rw_mm_cause
+
+3:	; Probably not in a loop, continue normal processing
+	move.d  current_pgd, $acr ; PGD
+	; Look up PMD in PGD
+	lsrq	24, $r0	; Get PMD index into PGD (bit 24-31)
+	move.d  [$acr], $acr	; PGD for the current process
+	addi	$r0.d, $acr, $acr
+	move	$s3, $r0	; rw_mm_cause
+	move.d  [$acr], $acr	; Get PMD
+	beq	8f
+	; Look up PTE in PMD
+	lsrq	PAGE_SHIFT, $r0
+	and.w	PAGE_MASK, $acr	; Remove PMD flags
+	and.d	0x7ff, $r0	; Get PTE index into PMD (bit 13-23)
+	addi    $r0.d, $acr, $acr
+	move.d  [$acr], $acr	; Get PTE
+	beq	9f
+	movem	[$sp], $r2	; Restore r0-r2 in delay slot
+	addq	12, $sp
+	; Store in TLB
+	move	$acr, $s5
+4:	; Return
+	move.d	[$sp+], $acr
+	move	[$sp], $srs
+	addq	4, $sp
+	rete
+	rfe
+
+5:      ; last_refill_cause is invalid
+	moveq	1, $r2
+        addq    4, $r1          ; Point to last_refill_cause
+	move.d	$r2, [$acr]	; refill_count = 1
+	move	$s3, $r0	; Get rw_mm_cause
+        ba      3b		; Continue normal processing
+	move.d	$r0,[$r1]	; last_refill_cause = rw_mm_cause
+
+6:      ; rw_mm_cause == last_refill_cause
+        move.d  [$acr], $r2     ; Get refill_count
+	cmpq	4, $r2		; refill_count > 4 ?
+	bhi	7f		;   yes
+	addq	1, $r2	        ; refill_count++
+	ba	3b		; Continue normal processing
+	move.d	$r2, [$acr]
+
+7:	; refill_count > 4, error
+	move.d	$acr, $r0       ; Save pointer to refill_count
+	clear.d	[$r0]		; refill_count = 0
+
+	;; rewind the short stack
+	movem	[$sp], $r2	; Restore r0-r2
+	addq	12, $sp
+	move.d	[$sp+], $acr
+	move	[$sp], $srs
+	addq	4, $sp
+	;; Keep it simple (slow), save all the regs.
+	SAVE_ALL
+	jsr	__flush_tlb_all
+	nop
+	ba	ret_from_intr	; Return
+	nop
+
+8:	; PMD missing, let the mm subsystem fix it up.
+	movem	[$sp], $r2	; Restore r0-r2
+9:      ; PTE missing, let the mm subsystem fix it up.
+	addq	12, $sp
+	move.d	[$sp+], $acr
+	move	[$sp], $srs
+	addq	4, $sp
+	SAVE_ALL
+	move    \mmu, $srs
+	move.d	$sp, $r11	; regs
+	clear.d	$r12		; Not a protection fault
+	move.w  PAGE_MASK, $acr
+	move    $s3, $r10	; rw_mm_cause
+	btstq   9, $r10		; Check if write access
+	smi     $r13
+	and.w	PAGE_MASK, $r10	; Get VPN (virtual address)
+	jsr	do_page_fault
+	and.w   $acr, $r10
+	; Return
+	ba	ret_from_intr
+	nop
+	.size   \handler, . - \handler
+.endm
+
+	; This is the MMU bus fault handlers.
+
+MMU_REFILL_HANDLER i_mmu_refill, 1
+MMU_BUS_FAULT_HANDLER i_mmu_invalid, 1, 0, 0
+MMU_BUS_FAULT_HANDLER i_mmu_access,  1, 0, 0
+MMU_BUS_FAULT_HANDLER i_mmu_execute, 1, 0, 1
+MMU_REFILL_HANDLER d_mmu_refill,  2
+MMU_BUS_FAULT_HANDLER d_mmu_invalid, 2, 0, 0
+MMU_BUS_FAULT_HANDLER d_mmu_access,  2, 0, 0
+MMU_BUS_FAULT_HANDLER d_mmu_write,   2, 1, 0
diff --git a/arch/cris/arch-v32/mm/tlb.c b/arch/cris/arch-v32/mm/tlb.c
new file mode 100644
index 000000000..c030d0206
--- /dev/null
+++ b/arch/cris/arch-v32/mm/tlb.c
@@ -0,0 +1,207 @@
+/*
+ * Low level TLB handling.
+ *
+ * Copyright (C) 2000-2003, Axis Communications AB.
+ *
+ * Authors:   Bjorn Wesen <bjornw@axis.com>
+ *            Tobias Anderberg <tobiasa@axis.com>, CRISv32 port.
+ */
+
+#include <asm/tlb.h>
+#include <asm/mmu_context.h>
+#include <arch/hwregs/asm/mmu_defs_asm.h>
+#include <arch/hwregs/supp_reg.h>
+
+#define UPDATE_TLB_SEL_IDX(val)					\
+do {								\
+	unsigned long tlb_sel;					\
+								\
+	tlb_sel = REG_FIELD(mmu, rw_mm_tlb_sel, idx, val);	\
+	SUPP_REG_WR(RW_MM_TLB_SEL, tlb_sel);			\
+} while(0)
+
+#define UPDATE_TLB_HILO(tlb_hi, tlb_lo)		\
+do {						\
+	SUPP_REG_WR(RW_MM_TLB_HI, tlb_hi);	\
+	SUPP_REG_WR(RW_MM_TLB_LO, tlb_lo);	\
+} while(0)
+
+/*
+ * The TLB can host up to 256 different mm contexts at the same time. The running
+ * context is found in the PID register. Each TLB entry contains a page_id that
+ * has to match the PID register to give a hit. page_id_map keeps track of which
+ * mm's is assigned to which page_id's, making sure it's known when to
+ * invalidate TLB entries.
+ *
+ * The last page_id is never running, it is used as an invalid page_id so that
+ * it's possible to make TLB entries that will nerver match.
+ *
+ * Note; the flushes needs to be atomic otherwise an interrupt hander that uses
+ * vmalloc'ed memory might cause a TLB load in the middle of a flush.
+ */
+
+/* Flush all TLB entries. */
+void
+__flush_tlb_all(void)
+{
+	int i;
+	int mmu;
+	unsigned long flags;
+	unsigned long mmu_tlb_hi;
+	unsigned long mmu_tlb_sel;
+
+	/*
+	 * Mask with 0xf so similar TLB entries aren't written in the same 4-way
+	 * entry group.
+	 */
+	local_irq_save(flags);
+
+	for (mmu = 1; mmu <= 2; mmu++) {
+		SUPP_BANK_SEL(mmu); /* Select the MMU */
+		for (i = 0; i < NUM_TLB_ENTRIES; i++) {
+			/* Store invalid entry */
+			mmu_tlb_sel = REG_FIELD(mmu, rw_mm_tlb_sel, idx, i);
+
+			mmu_tlb_hi = (REG_FIELD(mmu, rw_mm_tlb_hi, pid, INVALID_PAGEID)
+				    | REG_FIELD(mmu, rw_mm_tlb_hi, vpn, i & 0xf));
+
+			SUPP_REG_WR(RW_MM_TLB_SEL, mmu_tlb_sel);
+			SUPP_REG_WR(RW_MM_TLB_HI, mmu_tlb_hi);
+			SUPP_REG_WR(RW_MM_TLB_LO, 0);
+		}
+	}
+
+	local_irq_restore(flags);
+}
+
+/* Flush an entire user address space. */
+void
+__flush_tlb_mm(struct mm_struct *mm)
+{
+	int i;
+	int mmu;
+	unsigned long flags;
+	unsigned long page_id;
+	unsigned long tlb_hi;
+	unsigned long mmu_tlb_hi;
+
+	page_id = mm->context.page_id;
+
+	if (page_id == NO_CONTEXT)
+		return;
+
+	/* Mark the TLB entries that match the page_id as invalid. */
+	local_irq_save(flags);
+
+	for (mmu = 1; mmu <= 2; mmu++) {
+		SUPP_BANK_SEL(mmu);
+		for (i = 0; i < NUM_TLB_ENTRIES; i++) {
+			UPDATE_TLB_SEL_IDX(i);
+
+			/* Get the page_id */
+			SUPP_REG_RD(RW_MM_TLB_HI, tlb_hi);
+
+			/* Check if the page_id match. */
+			if ((tlb_hi & 0xff) == page_id) {
+				mmu_tlb_hi = (REG_FIELD(mmu, rw_mm_tlb_hi, pid,
+				                        INVALID_PAGEID)
+				            | REG_FIELD(mmu, rw_mm_tlb_hi, vpn,
+				                        i & 0xf));
+
+				UPDATE_TLB_HILO(mmu_tlb_hi, 0);
+			}
+		}
+	}
+
+	local_irq_restore(flags);
+}
+
+/* Invalidate a single page. */
+void
+__flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
+{
+	int i;
+	int mmu;
+	unsigned long page_id;
+	unsigned long flags;
+	unsigned long tlb_hi;
+	unsigned long mmu_tlb_hi;
+
+	page_id = vma->vm_mm->context.page_id;
+
+	if (page_id == NO_CONTEXT)
+		return;
+
+	addr &= PAGE_MASK;
+
+	/*
+	 * Invalidate those TLB entries that match both the mm context and the
+	 * requested virtual address.
+	 */
+	local_irq_save(flags);
+
+	for (mmu = 1; mmu <= 2; mmu++) {
+		SUPP_BANK_SEL(mmu);
+		for (i = 0; i < NUM_TLB_ENTRIES; i++) {
+			UPDATE_TLB_SEL_IDX(i);
+			SUPP_REG_RD(RW_MM_TLB_HI, tlb_hi);
+
+			/* Check if page_id and address matches */
+			if (((tlb_hi & 0xff) == page_id) &&
+			    ((tlb_hi & PAGE_MASK) == addr)) {
+				mmu_tlb_hi = REG_FIELD(mmu, rw_mm_tlb_hi, pid,
+				                       INVALID_PAGEID) | addr;
+
+				UPDATE_TLB_HILO(mmu_tlb_hi, 0);
+			}
+		}
+	}
+
+	local_irq_restore(flags);
+}
+
+/*
+ * Initialize the context related info for a new mm_struct
+ * instance.
+ */
+
+int
+init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+{
+	mm->context.page_id = NO_CONTEXT;
+	return 0;
+}
+
+static DEFINE_SPINLOCK(mmu_context_lock);
+
+/* Called in schedule() just before actually doing the switch_to. */
+void
+switch_mm(struct mm_struct *prev, struct mm_struct *next,
+	  struct task_struct *tsk)
+{
+	if (prev != next) {
+		int cpu = smp_processor_id();
+
+		/* Make sure there is a MMU context. */
+		spin_lock(&mmu_context_lock);
+		get_mmu_context(next);
+		cpumask_set_cpu(cpu, mm_cpumask(next));
+		spin_unlock(&mmu_context_lock);
+
+		/*
+		 * Remember the pgd for the fault handlers. Keep a separate
+		 * copy of it because current and active_mm might be invalid
+		 * at points where * there's still a need to derefer the pgd.
+		 */
+		per_cpu(current_pgd, cpu) = next->pgd;
+
+		/* Switch context in the MMU. */
+		if (tsk && task_thread_info(tsk)) {
+			SPEC_REG_WR(SPEC_REG_PID, next->context.page_id |
+				task_thread_info(tsk)->tls);
+		} else {
+			SPEC_REG_WR(SPEC_REG_PID, next->context.page_id);
+		}
+	}
+}
+