[ARM] 3370/2: ep93xx: add crunch support

Patch from Lennert Buytenhek

Add the necessary kernel bits for crunch task switching.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 305 insertions, 0 deletions

diff --git a/arch/arm/kernel/crunch-bits.S b/arch/arm/kernel/crunch-bits.S
new file mode 100644
index 000000000000..a26886758c67
--- /dev/null
+++ b/arch/arm/kernel/crunch-bits.S
@@ -0,0 +1,305 @@
+/*
+ * arch/arm/kernel/crunch-bits.S
+ * Cirrus MaverickCrunch context switching and handling
+ *
+ * Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
+ *
+ * Shamelessly stolen from the iWMMXt code by Nicolas Pitre, which is
+ * Copyright (c) 2003-2004, MontaVista Software, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/linkage.h>
+#include <asm/ptrace.h>
+#include <asm/thread_info.h>
+#include <asm/asm-offsets.h>
+#include <asm/arch/ep93xx-regs.h>
+
+/*
+ * We can't use hex constants here due to a bug in gas.
+ */
+#define CRUNCH_MVDX0		0
+#define CRUNCH_MVDX1		8
+#define CRUNCH_MVDX2		16
+#define CRUNCH_MVDX3		24
+#define CRUNCH_MVDX4		32
+#define CRUNCH_MVDX5		40
+#define CRUNCH_MVDX6		48
+#define CRUNCH_MVDX7		56
+#define CRUNCH_MVDX8		64
+#define CRUNCH_MVDX9		72
+#define CRUNCH_MVDX10		80
+#define CRUNCH_MVDX11		88
+#define CRUNCH_MVDX12		96
+#define CRUNCH_MVDX13		104
+#define CRUNCH_MVDX14		112
+#define CRUNCH_MVDX15		120
+#define CRUNCH_MVAX0L		128
+#define CRUNCH_MVAX0M		132
+#define CRUNCH_MVAX0H		136
+#define CRUNCH_MVAX1L		140
+#define CRUNCH_MVAX1M		144
+#define CRUNCH_MVAX1H		148
+#define CRUNCH_MVAX2L		152
+#define CRUNCH_MVAX2M		156
+#define CRUNCH_MVAX2H		160
+#define CRUNCH_MVAX3L		164
+#define CRUNCH_MVAX3M		168
+#define CRUNCH_MVAX3H		172
+#define CRUNCH_DSPSC		176
+
+#define CRUNCH_SIZE		184
+
+	.text
+
+/*
+ * Lazy switching of crunch coprocessor context
+ *
+ * r10 = struct thread_info pointer
+ * r9  = ret_from_exception
+ * lr  = undefined instr exit
+ *
+ * called from prefetch exception handler with interrupts disabled
+ */
+ENTRY(crunch_task_enable)
+	ldr	r8, =(EP93XX_APB_VIRT_BASE + 0x00130000)	@ syscon addr
+
+	ldr	r1, [r8, #0x80]
+	tst	r1, #0x00800000			@ access to crunch enabled?
+	movne	pc, lr				@ if so no business here
+	mov	r3, #0xaa			@ unlock syscon swlock
+	str	r3, [r8, #0xc0]
+	orr	r1, r1, #0x00800000		@ enable access to crunch
+	str	r1, [r8, #0x80]
+
+	ldr	r3, =crunch_owner
+	add	r0, r10, #TI_CRUNCH_STATE	@ get task crunch save area
+	ldr	r2, [sp, #60]			@ current task pc value
+	ldr	r1, [r3]			@ get current crunch owner
+	str	r0, [r3]			@ this task now owns crunch
+	sub	r2, r2, #4			@ adjust pc back
+	str	r2, [sp, #60]
+
+	ldr	r2, [r8, #0x80]
+	mov	r2, r2				@ flush out enable (@@@)
+
+	teq	r1, #0				@ test for last ownership
+	mov	lr, r9				@ normal exit from exception
+	beq	crunch_load			@ no owner, skip save
+
+crunch_save:
+	cfstr64		mvdx0, [r1, #CRUNCH_MVDX0]	@ save 64b registers
+	cfstr64		mvdx1, [r1, #CRUNCH_MVDX1]
+	cfstr64		mvdx2, [r1, #CRUNCH_MVDX2]
+	cfstr64		mvdx3, [r1, #CRUNCH_MVDX3]
+	cfstr64		mvdx4, [r1, #CRUNCH_MVDX4]
+	cfstr64		mvdx5, [r1, #CRUNCH_MVDX5]
+	cfstr64		mvdx6, [r1, #CRUNCH_MVDX6]
+	cfstr64		mvdx7, [r1, #CRUNCH_MVDX7]
+	cfstr64		mvdx8, [r1, #CRUNCH_MVDX8]
+	cfstr64		mvdx9, [r1, #CRUNCH_MVDX9]
+	cfstr64		mvdx10, [r1, #CRUNCH_MVDX10]
+	cfstr64		mvdx11, [r1, #CRUNCH_MVDX11]
+	cfstr64		mvdx12, [r1, #CRUNCH_MVDX12]
+	cfstr64		mvdx13, [r1, #CRUNCH_MVDX13]
+	cfstr64		mvdx14, [r1, #CRUNCH_MVDX14]
+	cfstr64		mvdx15, [r1, #CRUNCH_MVDX15]
+
+#ifdef __ARMEB__
+#error fix me for ARMEB
+#endif
+
+	cfmv32al	mvfx0, mvax0			@ save 72b accumulators
+	cfstr32		mvfx0, [r1, #CRUNCH_MVAX0L]
+	cfmv32am	mvfx0, mvax0
+	cfstr32		mvfx0, [r1, #CRUNCH_MVAX0M]
+	cfmv32ah	mvfx0, mvax0
+	cfstr32		mvfx0, [r1, #CRUNCH_MVAX0H]
+	cfmv32al	mvfx0, mvax1
+	cfstr32		mvfx0, [r1, #CRUNCH_MVAX1L]
+	cfmv32am	mvfx0, mvax1
+	cfstr32		mvfx0, [r1, #CRUNCH_MVAX1M]
+	cfmv32ah	mvfx0, mvax1
+	cfstr32		mvfx0, [r1, #CRUNCH_MVAX1H]
+	cfmv32al	mvfx0, mvax2
+	cfstr32		mvfx0, [r1, #CRUNCH_MVAX2L]
+	cfmv32am	mvfx0, mvax2
+	cfstr32		mvfx0, [r1, #CRUNCH_MVAX2M]
+	cfmv32ah	mvfx0, mvax2
+	cfstr32		mvfx0, [r1, #CRUNCH_MVAX2H]
+	cfmv32al	mvfx0, mvax3
+	cfstr32		mvfx0, [r1, #CRUNCH_MVAX3L]
+	cfmv32am	mvfx0, mvax3
+	cfstr32		mvfx0, [r1, #CRUNCH_MVAX3M]
+	cfmv32ah	mvfx0, mvax3
+	cfstr32		mvfx0, [r1, #CRUNCH_MVAX3H]
+
+	cfmv32sc	mvdx0, dspsc			@ save status word
+	cfstr64		mvdx0, [r1, #CRUNCH_DSPSC]
+
+	teq		r0, #0				@ anything to load?
+	cfldr64eq	mvdx0, [r1, #CRUNCH_MVDX0]	@ mvdx0 was clobbered
+	moveq		pc, lr
+
+crunch_load:
+	cfldr64		mvdx0, [r0, #CRUNCH_DSPSC]	@ load status word
+	cfmvsc32	dspsc, mvdx0
+
+	cfldr32		mvfx0, [r0, #CRUNCH_MVAX0L]	@ load 72b accumulators
+	cfmval32	mvax0, mvfx0
+	cfldr32		mvfx0, [r0, #CRUNCH_MVAX0M]
+	cfmvam32	mvax0, mvfx0
+	cfldr32		mvfx0, [r0, #CRUNCH_MVAX0H]
+	cfmvah32	mvax0, mvfx0
+	cfldr32		mvfx0, [r0, #CRUNCH_MVAX1L]
+	cfmval32	mvax1, mvfx0
+	cfldr32		mvfx0, [r0, #CRUNCH_MVAX1M]
+	cfmvam32	mvax1, mvfx0
+	cfldr32		mvfx0, [r0, #CRUNCH_MVAX1H]
+	cfmvah32	mvax1, mvfx0
+	cfldr32		mvfx0, [r0, #CRUNCH_MVAX2L]
+	cfmval32	mvax2, mvfx0
+	cfldr32		mvfx0, [r0, #CRUNCH_MVAX2M]
+	cfmvam32	mvax2, mvfx0
+	cfldr32		mvfx0, [r0, #CRUNCH_MVAX2H]
+	cfmvah32	mvax2, mvfx0
+	cfldr32		mvfx0, [r0, #CRUNCH_MVAX3L]
+	cfmval32	mvax3, mvfx0
+	cfldr32		mvfx0, [r0, #CRUNCH_MVAX3M]
+	cfmvam32	mvax3, mvfx0
+	cfldr32		mvfx0, [r0, #CRUNCH_MVAX3H]
+	cfmvah32	mvax3, mvfx0
+
+	cfldr64		mvdx0, [r0, #CRUNCH_MVDX0]	@ load 64b registers
+	cfldr64		mvdx1, [r0, #CRUNCH_MVDX1]
+	cfldr64		mvdx2, [r0, #CRUNCH_MVDX2]
+	cfldr64		mvdx3, [r0, #CRUNCH_MVDX3]
+	cfldr64		mvdx4, [r0, #CRUNCH_MVDX4]
+	cfldr64		mvdx5, [r0, #CRUNCH_MVDX5]
+	cfldr64		mvdx6, [r0, #CRUNCH_MVDX6]
+	cfldr64		mvdx7, [r0, #CRUNCH_MVDX7]
+	cfldr64		mvdx8, [r0, #CRUNCH_MVDX8]
+	cfldr64		mvdx9, [r0, #CRUNCH_MVDX9]
+	cfldr64		mvdx10, [r0, #CRUNCH_MVDX10]
+	cfldr64		mvdx11, [r0, #CRUNCH_MVDX11]
+	cfldr64		mvdx12, [r0, #CRUNCH_MVDX12]
+	cfldr64		mvdx13, [r0, #CRUNCH_MVDX13]
+	cfldr64		mvdx14, [r0, #CRUNCH_MVDX14]
+	cfldr64		mvdx15, [r0, #CRUNCH_MVDX15]
+
+	mov	pc, lr
+
+/*
+ * Back up crunch regs to save area and disable access to them
+ * (mainly for gdb or sleep mode usage)
+ *
+ * r0 = struct thread_info pointer of target task or NULL for any
+ */
+ENTRY(crunch_task_disable)
+	stmfd	sp!, {r4, r5, lr}
+
+	mrs	ip, cpsr
+	orr	r2, ip, #PSR_I_BIT		@ disable interrupts
+	msr	cpsr_c, r2
+
+	ldr	r4, =(EP93XX_APB_VIRT_BASE + 0x00130000)	@ syscon addr
+
+	ldr	r3, =crunch_owner
+	add	r2, r0, #TI_CRUNCH_STATE	@ get task crunch save area
+	ldr	r1, [r3]			@ get current crunch owner
+	teq	r1, #0				@ any current owner?
+	beq	1f				@ no: quit
+	teq	r0, #0				@ any owner?
+	teqne	r1, r2				@ or specified one?
+	bne	1f				@ no: quit
+
+	ldr	r5, [r4, #0x80]			@ enable access to crunch
+	mov	r2, #0xaa
+	str	r2, [r4, #0xc0]
+	orr	r5, r5, #0x00800000
+	str	r5, [r4, #0x80]
+
+	mov	r0, #0				@ nothing to load
+	str	r0, [r3]			@ no more current owner
+	ldr	r2, [r4, #0x80]			@ flush out enable (@@@)
+	mov	r2, r2
+	bl	crunch_save
+
+	mov	r2, #0xaa			@ disable access to crunch
+	str	r2, [r4, #0xc0]
+	bic	r5, r5, #0x00800000
+	str	r5, [r4, #0x80]
+	ldr	r5, [r4, #0x80]			@ flush out enable (@@@)
+	mov	r5, r5
+
+1:	msr	cpsr_c, ip			@ restore interrupt mode
+	ldmfd	sp!, {r4, r5, pc}
+
+/*
+ * Copy crunch state to given memory address
+ *
+ * r0 = struct thread_info pointer of target task
+ * r1 = memory address where to store crunch state
+ *
+ * this is called mainly in the creation of signal stack frames
+ */
+ENTRY(crunch_task_copy)
+	mrs	ip, cpsr
+	orr	r2, ip, #PSR_I_BIT		@ disable interrupts
+	msr	cpsr_c, r2
+
+	ldr	r3, =crunch_owner
+	add	r2, r0, #TI_CRUNCH_STATE	@ get task crunch save area
+	ldr	r3, [r3]			@ get current crunch owner
+	teq	r2, r3				@ does this task own it...
+	beq	1f
+
+	@ current crunch values are in the task save area
+	msr	cpsr_c, ip			@ restore interrupt mode
+	mov	r0, r1
+	mov	r1, r2
+	mov	r2, #CRUNCH_SIZE
+	b	memcpy
+
+1:	@ this task owns crunch regs -- grab a copy from there
+	mov	r0, #0				@ nothing to load
+	mov	r3, lr				@ preserve return address
+	bl	crunch_save
+	msr	cpsr_c, ip			@ restore interrupt mode
+	mov	pc, r3
+
+/*
+ * Restore crunch state from given memory address
+ *
+ * r0 = struct thread_info pointer of target task
+ * r1 = memory address where to get crunch state from
+ *
+ * this is used to restore crunch state when unwinding a signal stack frame
+ */
+ENTRY(crunch_task_restore)
+	mrs	ip, cpsr
+	orr	r2, ip, #PSR_I_BIT		@ disable interrupts
+	msr	cpsr_c, r2
+
+	ldr	r3, =crunch_owner
+	add	r2, r0, #TI_CRUNCH_STATE	@ get task crunch save area
+	ldr	r3, [r3]			@ get current crunch owner
+	teq	r2, r3				@ does this task own it...
+	beq	1f
+
+	@ this task doesn't own crunch regs -- use its save area
+	msr	cpsr_c, ip			@ restore interrupt mode
+	mov	r0, r2
+	mov	r2, #CRUNCH_SIZE
+	b	memcpy
+
+1:	@ this task owns crunch regs -- load them directly
+	mov	r0, r1
+	mov	r1, #0				@ nothing to save
+	mov	r3, lr				@ preserve return address
+	bl	crunch_load
+	msr	cpsr_c, ip			@ restore interrupt mode
+	mov	pc, r3