[PATCH] avr32 architecture

This adds support for the Atmel AVR32 architecture as well as the AT32AP7000
CPU and the AT32STK1000 development board.

AVR32 is a new high-performance 32-bit RISC microprocessor core, designed for
cost-sensitive embedded applications, with particular emphasis on low power
consumption and high code density.  The AVR32 architecture is not binary
compatible with earlier 8-bit AVR architectures.

The AVR32 architecture, including the instruction set, is described by the
AVR32 Architecture Manual, available from

http://www.atmel.com/dyn/resources/prod_documents/doc32000.pdf

The Atmel AT32AP7000 is the first CPU implementing the AVR32 architecture.  It
features a 7-stage pipeline, 16KB instruction and data caches and a full
Memory Management Unit.  It also comes with a large set of integrated
peripherals, many of which are shared with the AT91 ARM-based controllers from
Atmel.

Full data sheet is available from

http://www.atmel.com/dyn/resources/prod_documents/doc32003.pdf

while the CPU core implementation including caches and MMU is documented by
the AVR32 AP Technical Reference, available from

http://www.atmel.com/dyn/resources/prod_documents/doc32001.pdf

Information about the AT32STK1000 development board can be found at

http://www.atmel.com/dyn/products/tools_card.asp?tool_id=3918

including a BSP CD image with an earlier version of this patch, development
tools (binaries and source/patches) and a root filesystem image suitable for
booting from SD card.

Alternatively, there's a preliminary "getting started" guide available at
http://avr32linux.org/twiki/bin/view/Main/GettingStarted which provides links
to the sources and patches you will need in order to set up a cross-compiling
environment for avr32-linux.

This patch, as well as the other patches included with the BSP and the
toolchain patches, is actively supported by Atmel Corporation.

[dmccr@us.ibm.com: Fix more pxx_page macro locations]
[bunk@stusta.de: fix `make defconfig']
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Dave McCracken <dmccr@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 276 insertions, 0 deletions

diff --git a/arch/avr32/kernel/process.c b/arch/avr32/kernel/process.c
new file mode 100644
index 000000000000..317dc50945f2
--- /dev/null
+++ b/arch/avr32/kernel/process.c
@@ -0,0 +1,276 @@
+/*
+ * Copyright (C) 2004-2006 Atmel Corporation
+ *
+ * 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/sched.h>
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/fs.h>
+#include <linux/ptrace.h>
+#include <linux/reboot.h>
+#include <linux/unistd.h>
+
+#include <asm/sysreg.h>
+#include <asm/ocd.h>
+
+void (*pm_power_off)(void) = NULL;
+EXPORT_SYMBOL(pm_power_off);
+
+/*
+ * This file handles the architecture-dependent parts of process handling..
+ */
+
+void cpu_idle(void)
+{
+	/* endless idle loop with no priority at all */
+	while (1) {
+		/* TODO: Enter sleep mode */
+		while (!need_resched())
+			cpu_relax();
+		preempt_enable_no_resched();
+		schedule();
+		preempt_disable();
+	}
+}
+
+void machine_halt(void)
+{
+}
+
+void machine_power_off(void)
+{
+}
+
+void machine_restart(char *cmd)
+{
+	__mtdr(DBGREG_DC, DC_DBE);
+	__mtdr(DBGREG_DC, DC_RES);
+	while (1) ;
+}
+
+/*
+ * PC is actually discarded when returning from a system call -- the
+ * return address must be stored in LR. This function will make sure
+ * LR points to do_exit before starting the thread.
+ *
+ * Also, when returning from fork(), r12 is 0, so we must copy the
+ * argument as well.
+ *
+ *  r0 : The argument to the main thread function
+ *  r1 : The address of do_exit
+ *  r2 : The address of the main thread function
+ */
+asmlinkage extern void kernel_thread_helper(void);
+__asm__("	.type	kernel_thread_helper, @function\n"
+	"kernel_thread_helper:\n"
+	"	mov	r12, r0\n"
+	"	mov	lr, r2\n"
+	"	mov	pc, r1\n"
+	"	.size	kernel_thread_helper, . - kernel_thread_helper");
+
+int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
+{
+	struct pt_regs regs;
+
+	memset(&regs, 0, sizeof(regs));
+
+	regs.r0 = (unsigned long)arg;
+	regs.r1 = (unsigned long)fn;
+	regs.r2 = (unsigned long)do_exit;
+	regs.lr = (unsigned long)kernel_thread_helper;
+	regs.pc = (unsigned long)kernel_thread_helper;
+	regs.sr = MODE_SUPERVISOR;
+
+	return do_fork(flags | CLONE_VM | CLONE_UNTRACED,
+		       0, &regs, 0, NULL, NULL);
+}
+EXPORT_SYMBOL(kernel_thread);
+
+/*
+ * Free current thread data structures etc
+ */
+void exit_thread(void)
+{
+	/* nothing to do */
+}
+
+void flush_thread(void)
+{
+	/* nothing to do */
+}
+
+void release_thread(struct task_struct *dead_task)
+{
+	/* do nothing */
+}
+
+static const char *cpu_modes[] = {
+	"Application", "Supervisor", "Interrupt level 0", "Interrupt level 1",
+	"Interrupt level 2", "Interrupt level 3", "Exception", "NMI"
+};
+
+void show_regs(struct pt_regs *regs)
+{
+	unsigned long sp = regs->sp;
+	unsigned long lr = regs->lr;
+	unsigned long mode = (regs->sr & MODE_MASK) >> MODE_SHIFT;
+
+	if (!user_mode(regs))
+		sp = (unsigned long)regs + FRAME_SIZE_FULL;
+
+	print_symbol("PC is at %s\n", instruction_pointer(regs));
+	print_symbol("LR is at %s\n", lr);
+	printk("pc : [<%08lx>]    lr : [<%08lx>]    %s\n"
+	       "sp : %08lx  r12: %08lx  r11: %08lx\n",
+	       instruction_pointer(regs),
+	       lr, print_tainted(), sp, regs->r12, regs->r11);
+	printk("r10: %08lx  r9 : %08lx  r8 : %08lx\n",
+	       regs->r10, regs->r9, regs->r8);
+	printk("r7 : %08lx  r6 : %08lx  r5 : %08lx  r4 : %08lx\n",
+	       regs->r7, regs->r6, regs->r5, regs->r4);
+	printk("r3 : %08lx  r2 : %08lx  r1 : %08lx  r0 : %08lx\n",
+	       regs->r3, regs->r2, regs->r1, regs->r0);
+	printk("Flags: %c%c%c%c%c\n",
+	       regs->sr & SR_Q ? 'Q' : 'q',
+	       regs->sr & SR_V ? 'V' : 'v',
+	       regs->sr & SR_N ? 'N' : 'n',
+	       regs->sr & SR_Z ? 'Z' : 'z',
+	       regs->sr & SR_C ? 'C' : 'c');
+	printk("Mode bits: %c%c%c%c%c%c%c%c%c\n",
+	       regs->sr & SR_H ? 'H' : 'h',
+	       regs->sr & SR_R ? 'R' : 'r',
+	       regs->sr & SR_J ? 'J' : 'j',
+	       regs->sr & SR_EM ? 'E' : 'e',
+	       regs->sr & SR_I3M ? '3' : '.',
+	       regs->sr & SR_I2M ? '2' : '.',
+	       regs->sr & SR_I1M ? '1' : '.',
+	       regs->sr & SR_I0M ? '0' : '.',
+	       regs->sr & SR_GM ? 'G' : 'g');
+	printk("CPU Mode: %s\n", cpu_modes[mode]);
+
+	show_trace(NULL, (unsigned long *)sp, regs);
+}
+EXPORT_SYMBOL(show_regs);
+
+/* Fill in the fpu structure for a core dump. This is easy -- we don't have any */
+int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
+{
+	/* Not valid */
+	return 0;
+}
+
+asmlinkage void ret_from_fork(void);
+
+int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
+		unsigned long unused,
+		struct task_struct *p, struct pt_regs *regs)
+{
+	struct pt_regs *childregs;
+
+	childregs = ((struct pt_regs *)(THREAD_SIZE + (unsigned long)p->thread_info)) - 1;
+	*childregs = *regs;
+
+	if (user_mode(regs))
+		childregs->sp = usp;
+	else
+		childregs->sp = (unsigned long)p->thread_info + THREAD_SIZE;
+
+	childregs->r12 = 0; /* Set return value for child */
+
+	p->thread.cpu_context.sr = MODE_SUPERVISOR | SR_GM;
+	p->thread.cpu_context.ksp = (unsigned long)childregs;
+	p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
+
+	return 0;
+}
+
+/* r12-r8 are dummy parameters to force the compiler to use the stack */
+asmlinkage int sys_fork(struct pt_regs *regs)
+{
+	return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);
+}
+
+asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp,
+			 unsigned long parent_tidptr,
+			 unsigned long child_tidptr, struct pt_regs *regs)
+{
+	if (!newsp)
+		newsp = regs->sp;
+	return do_fork(clone_flags, newsp, regs, 0,
+		       (int __user *)parent_tidptr,
+		       (int __user *)child_tidptr);
+}
+
+asmlinkage int sys_vfork(struct pt_regs *regs)
+{
+	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs,
+		       0, NULL, NULL);
+}
+
+asmlinkage int sys_execve(char __user *ufilename, char __user *__user *uargv,
+			  char __user *__user *uenvp, struct pt_regs *regs)
+{
+	int error;
+	char *filename;
+
+	filename = getname(ufilename);
+	error = PTR_ERR(filename);
+	if (IS_ERR(filename))
+		goto out;
+
+	error = do_execve(filename, uargv, uenvp, regs);
+	if (error == 0)
+		current->ptrace &= ~PT_DTRACE;
+	putname(filename);
+
+out:
+	return error;
+}
+
+
+/*
+ * This function is supposed to answer the question "who called
+ * schedule()?"
+ */
+unsigned long get_wchan(struct task_struct *p)
+{
+	unsigned long pc;
+	unsigned long stack_page;
+
+	if (!p || p == current || p->state == TASK_RUNNING)
+		return 0;
+
+	stack_page = (unsigned long)p->thread_info;
+	BUG_ON(!stack_page);
+
+	/*
+	 * The stored value of PC is either the address right after
+	 * the call to __switch_to() or ret_from_fork.
+	 */
+	pc = thread_saved_pc(p);
+	if (in_sched_functions(pc)) {
+#ifdef CONFIG_FRAME_POINTER
+		unsigned long fp = p->thread.cpu_context.r7;
+		BUG_ON(fp < stack_page || fp > (THREAD_SIZE + stack_page));
+		pc = *(unsigned long *)fp;
+#else
+		/*
+		 * We depend on the frame size of schedule here, which
+		 * is actually quite ugly. It might be possible to
+		 * determine the frame size automatically at build
+		 * time by doing this:
+		 *   - compile sched.c
+		 *   - disassemble the resulting sched.o
+		 *   - look for 'sub sp,??' shortly after '<schedule>:'
+		 */
+		unsigned long sp = p->thread.cpu_context.ksp + 16;
+		BUG_ON(sp < stack_page || sp > (THREAD_SIZE + stack_page));
+		pc = *(unsigned long *)sp;
+#endif
+	}
+
+	return pc;
+}