Hexagon: add support for ARCH_PFN_OFFSET

Add support for loading the kernel at a physical offset. The
offset should still be 4M aligned.

Signed-off-by: Richard Kuo <[e-mail]>

arch/hexagon/Kconfig

···
 	  Qualcomm Hexagon is a processor architecture designed for high
 	  performance and low power across a wide variety of applications.
 
+
 config HEXAGON_ARCH_V1
 	bool
 
···
 
 config HEXAGON_ARCH_V4
 	bool
+
+config HEXAGON_PHYS_OFFSET
+	def_bool y
+	---help---
+	  Platforms that don't load the kernel at zero set this.
 
 config FRAME_POINTER
 	def_bool y

arch/hexagon/include/asm/hexagon_vm.h

···
  * for tracing/debugging.
  */
 
-/*
- * Lets make this stuff visible only if configured,
- * so we can unconditionally include the file.
- */
+#define HVM_TRAP1_VMVERSION		0
+#define HVM_TRAP1_VMRTE			1
+#define HVM_TRAP1_VMSETVEC		2
+#define HVM_TRAP1_VMSETIE		3
+#define HVM_TRAP1_VMGETIE		4
+#define HVM_TRAP1_VMINTOP		5
+#define HVM_TRAP1_VMCLRMAP		10
+#define HVM_TRAP1_VMNEWMAP		11
+#define HVM_TRAP1_FORMERLY_VMWIRE	12
+#define HVM_TRAP1_VMCACHE		13
+#define HVM_TRAP1_VMGETTIME		14
+#define HVM_TRAP1_VMSETTIME		15
+#define HVM_TRAP1_VMWAIT		16
+#define HVM_TRAP1_VMYIELD		17
+#define HVM_TRAP1_VMSTART		18
+#define HVM_TRAP1_VMSTOP		19
+#define HVM_TRAP1_VMVPID		20
+#define HVM_TRAP1_VMSETREGS		21
+#define HVM_TRAP1_VMGETREGS		22
+#define HVM_TRAP1_VMTIMEROP		24
 
 #ifndef __ASSEMBLY__
 
···
 
 #else /* Only assembly code should reference these */
 
-#define HVM_TRAP1_VMRTE			1
-#define HVM_TRAP1_VMSETVEC		2
-#define HVM_TRAP1_VMSETIE		3
-#define HVM_TRAP1_VMGETIE		4
-#define HVM_TRAP1_VMINTOP		5
-#define HVM_TRAP1_VMCLRMAP		10
-#define HVM_TRAP1_VMNEWMAP		11
-#define HVM_TRAP1_FORMERLY_VMWIRE	12
-#define HVM_TRAP1_VMCACHE		13
-#define HVM_TRAP1_VMGETTIME		14
-#define HVM_TRAP1_VMSETTIME		15
-#define HVM_TRAP1_VMWAIT		16
-#define HVM_TRAP1_VMYIELD		17
-#define HVM_TRAP1_VMSTART		18
-#define HVM_TRAP1_VMSTOP		19
-#define HVM_TRAP1_VMVPID		20
-#define HVM_TRAP1_VMSETREGS		21
-#define HVM_TRAP1_VMGETREGS		22
-
 #endif /* __ASSEMBLY__ */
 
 /*
···
 #define HVM_VMEST_UM_MSK	1
 #define HVM_VMEST_IE_SFT	30
 #define HVM_VMEST_IE_MSK	1
+#define HVM_VMEST_SS_SFT	29
+#define HVM_VMEST_SS_MSK	1
 #define HVM_VMEST_EVENTNUM_SFT	16
 #define HVM_VMEST_EVENTNUM_MSK	0xff
 #define HVM_VMEST_CAUSE_SFT	0
···
 #define HVM_GE_C_INVI	0x15
 #define HVM_GE_C_PRIVI	0x1B
 #define HVM_GE_C_XMAL	0x1C
+#define HVM_GE_C_WREG	0x1D
+#define HVM_GE_C_PCAL	0x1E
 #define HVM_GE_C_RMAL	0x20
 #define HVM_GE_C_WMAL	0x21
 #define HVM_GE_C_RPROT	0x22

arch/hexagon/include/asm/mem-layout.h

···
 #define PAGE_OFFSET			_AC(0xc0000000, UL)
 
 /*
- * LOAD_ADDRESS is the physical/linear address of where in memory
- * the kernel gets loaded. The 12 least significant bits must be zero (0)
- * due to limitations on setting the EVB
- *
+ * Compiling for a platform that needs a crazy physical offset
+ * (like if the memory starts at 1GB and up) means we need
+ * an actual PHYS_OFFSET.  Should be set up in head.S.
  */
 
-#ifndef LOAD_ADDRESS
-#define LOAD_ADDRESS			0x00000000
+#ifdef CONFIG_HEXAGON_PHYS_OFFSET
+#ifndef __ASSEMBLY__
+extern unsigned long	__phys_offset;
 #endif
+#define PHYS_OFFSET	__phys_offset
+#endif
+
+#ifndef PHYS_OFFSET
+#define PHYS_OFFSET	0
+#endif
+
+#define PHYS_PFN_OFFSET	(PHYS_OFFSET >> PAGE_SHIFT)
+#define ARCH_PFN_OFFSET	PHYS_PFN_OFFSET
 
 #define TASK_SIZE			(PAGE_OFFSET)
 

arch/hexagon/include/asm/page.h

···
  * MIPS says they're only used during mem_init.
  * also, check if we need a PHYS_OFFSET.
  */
-#define __pa(x) ((unsigned long)(x) - PAGE_OFFSET)
-#define __va(x) ((void *)((unsigned long)(x) + PAGE_OFFSET))
+#define __pa(x) ((unsigned long)(x) - PAGE_OFFSET + PHYS_OFFSET)
+#define __va(x) ((void *)((unsigned long)(x) - PHYS_OFFSET + PAGE_OFFSET))
 
 /* The "page frame" descriptor is defined in linux/mm.h */
 struct page;
···
  */
 #define kern_addr_valid(addr)   (1)
 
+#include <asm/mem-layout.h>
 #include <asm-generic/memory_model.h>
 /* XXX Todo: implement assembly-optimized version of getorder. */
 #include <asm-generic/getorder.h>

arch/hexagon/kernel/head.S

···
 	 * Symbol is kernel segment address, but we need
 	 * the logical/physical address.
 	 */
-	r24 = asl(r24, #2)
-	r24 = lsr(r24, #2)
+	r25 = pc;
+	r2.h = #0xffc0;
+	r2.l = #0x0000;
+	r25 = and(r2,r25);	/*  R25 holds PHYS_OFFSET now  */
+	r1.h = #HI(PAGE_OFFSET);
+	r1.l = #LO(PAGE_OFFSET);
+	r24 = sub(r24,r1);	/* swapper_pg_dir - PAGE_OFFSET */
+	r24 = add(r24,r25);	/* + PHYS_OFFSET */
 
-	r0 = r24
+	r0 = r24;  /* aka __pa(swapper_pg_dir)  */
 
 	/*
-	 * Initialize a 16MB PTE to make the virtual and physical
+	 * Initialize page dir to make the virtual and physical
 	 * addresses where the kernel was loaded be identical.
+	 * Done in 4MB chunks.
 	 */
 #define PTE_BITS ( __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X	\
 		  | __HEXAGON_C_WB_L2 << 6			\
···
 
 	r2 = sub(r2,r0);
 	call memset;
+
+	/*  Set PHYS_OFFSET; should still be in R25 */
+#ifdef CONFIG_HEXAGON_PHYS_OFFSET
+	r0.l = #LO(__phys_offset);
+	r0.h = #HI(__phys_offset);
+	memw(r0) = r25;
+#endif
 
 	/* Time to make the doughnuts.   */
 	call start_kernel

arch/hexagon/kernel/setup.c

···
 	 */
 	__vmsetvec(_K_VM_event_vector);
 
+	printk(KERN_INFO "PHYS_OFFSET=0x%08x\n", PHYS_OFFSET);
+
 	/*
 	 * Simulator has a few differences from the hardware.
 	 * For now, check uninitialized-but-mapped memory

arch/hexagon/kernel/vmlinux.lds.S

···
  * 02110-1301, USA.
  */
 
-#define LOAD_OFFSET PAGE_OFFSET
-
 #include <asm-generic/vmlinux.lds.h>
 #include <asm/asm-offsets.h>	/*  Most of the kernel defines are here  */
 #include <asm/mem-layout.h>	/*  except for page_offset  */
···
 
 #define PAGE_SIZE _PAGE_SIZE
 
-/*  This LOAD_OFFSET is temporary for debugging on the simulator; it may change
-    for hypervisor pseudo-physical memory.  */
-
-
 SECTIONS
 {
-	. = PAGE_OFFSET + LOAD_ADDRESS;
+	. = PAGE_OFFSET;
 
 	__init_begin = .;
 	HEAD_TEXT_SECTION
···
 
         . = ALIGN(_PAGE_SIZE);
 	_stext = .;
-	.text : AT(ADDR(.text) - LOAD_OFFSET) {
+	.text : AT(ADDR(.text)) {
 		_text = .;
 		TEXT_TEXT
 		SCHED_TEXT

arch/hexagon/mm/init.c

···
  * Define a startpg just past the end of the kernel image and a lastpg
  * that corresponds to the end of real or simulated platform memory.
  */
-#define bootmem_startpg (PFN_UP(((unsigned long) _end) - PAGE_OFFSET))
+#define bootmem_startpg (PFN_UP(((unsigned long) _end) - PAGE_OFFSET + PHYS_OFFSET))
 
-unsigned long bootmem_lastpg;  /*  Should be set by platform code  */
+unsigned long bootmem_lastpg;	/*  Should be set by platform code  */
+unsigned long __phys_offset;	/*  physical kernel offset >> 12  */
 
 /*  Set as variable to limit PMD copies  */
 int max_kernel_seg = 0x303;
···
 /*  indicate pfn's of high memory  */
 unsigned long highstart_pfn, highend_pfn;
 
-/* struct mmu_gather defined in asm-generic.h;  */
 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
 
 /* Default cache attribute for newly created page tables */
···
 {
 	/*  No idea where this is actually declared.  Seems to evade LXR.  */
 	totalram_pages += free_all_bootmem();
-	num_physpages = bootmem_lastpg;	/*  seriously, what?  */
+	num_physpages = bootmem_lastpg-ARCH_PFN_OFFSET;
 
 	printk(KERN_INFO "totalram_pages = %ld\n", totalram_pages);
 
···
 	 * This needs to change for highmem setups.
 	 */
 
+	/*  Prior to this, bootmem_lastpg is actually mem size  */
+	bootmem_lastpg += ARCH_PFN_OFFSET;
+
 	/* Memory size needs to be a multiple of 16M */
 	bootmem_lastpg = PFN_DOWN((bootmem_lastpg << PAGE_SHIFT) &
 		~((BIG_KERNEL_PAGE_SIZE) - 1));
···
 	 * Reserve the top DMA_RESERVE bytes of RAM for DMA (uncached)
 	 * memory allocation
 	 */
-	bootmap_size = init_bootmem(bootmem_startpg, bootmem_lastpg -
-				    PFN_DOWN(DMA_RESERVED_BYTES));
+
+	max_low_pfn = bootmem_lastpg - PFN_DOWN(DMA_RESERVED_BYTES);
+	min_low_pfn = ARCH_PFN_OFFSET;
+	bootmap_size =  init_bootmem_node(NODE_DATA(0), bootmem_startpg, min_low_pfn, max_low_pfn);
 
 	printk(KERN_INFO "bootmem_startpg:  0x%08lx\n", bootmem_startpg);
 	printk(KERN_INFO "bootmem_lastpg:  0x%08lx\n", bootmem_lastpg);
 	printk(KERN_INFO "bootmap_size:  %d\n", bootmap_size);
+	printk(KERN_INFO "min_low_pfn:  0x%08lx\n", min_low_pfn);
 	printk(KERN_INFO "max_low_pfn:  0x%08lx\n", max_low_pfn);
 
 	/*
···
 	/*  this actually only goes to the end of the first gig  */
 	segtable_end = segtable + (1<<(30-22));
 
-	/*  Move forward to the start of empty pages  */
-	segtable += bootmem_lastpg >> (22-PAGE_SHIFT);
+	/*
+	 * Move forward to the start of empty pages; take into account
+	 * phys_offset shift.
+	 */
 
+	segtable += (bootmem_lastpg-ARCH_PFN_OFFSET)>>(22-PAGE_SHIFT);
 	{
-	    int i;
+		int i;
 
-	    for (i = 1 ; i <= DMA_RESERVE ; i++)
-		segtable[-i] = ((segtable[-i] & __HVM_PTE_PGMASK_4MB)
+		for (i = 1 ; i <= DMA_RESERVE ; i++)
+			segtable[-i] = ((segtable[-i] & __HVM_PTE_PGMASK_4MB)
 				| __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X
 				| __HEXAGON_C_UNC << 6
 				| __HVM_PDE_S_4MB);
···
 	 * Free all the memory that wasn't taken up by the bootmap, the DMA
 	 * reserve, or kernel itself.
 	 */
-	free_bootmem(PFN_PHYS(bootmem_startpg)+bootmap_size,
+	free_bootmem(PFN_PHYS(bootmem_startpg) + bootmap_size,
 		     PFN_PHYS(bootmem_lastpg - bootmem_startpg) - bootmap_size -
 		     DMA_RESERVED_BYTES);