blackfin architecture

This adds support for the Analog Devices Blackfin processor architecture, and
currently supports the BF533, BF532, BF531, BF537, BF536, BF534, and BF561
(Dual Core) devices, with a variety of development platforms including those
avaliable from Analog Devices (BF533-EZKit, BF533-STAMP, BF537-STAMP,
BF561-EZKIT), and Bluetechnix!  Tinyboards.

The Blackfin architecture was jointly developed by Intel and Analog Devices
Inc.  (ADI) as the Micro Signal Architecture (MSA) core and introduced it in
December of 2000.  Since then ADI has put this core into its Blackfin
processor family of devices.  The Blackfin core has the advantages of a clean,
orthogonal,RISC-like microprocessor instruction set.  It combines a dual-MAC
(Multiply/Accumulate), state-of-the-art signal processing engine and
single-instruction, multiple-data (SIMD) multimedia capabilities into a single
instruction-set architecture.

The Blackfin architecture, including the instruction set, is described by the
ADSP-BF53x/BF56x Blackfin Processor Programming Reference
http://blackfin.uclinux.org/gf/download/frsrelease/29/2549/Blackfin_PRM.pdf

The Blackfin processor is already supported by major releases of gcc, and
there are binary and source rpms/tarballs for many architectures at:
http://blackfin.uclinux.org/gf/project/toolchain/frs There is complete
documentation, including "getting started" guides available at:
http://docs.blackfin.uclinux.org/ which provides links to the sources and
patches you will need in order to set up a cross-compiling environment for
bfin-linux-uclibc

This patch, as well as the other patches (toolchain, distribution,
uClibc) are actively supported by Analog Devices Inc, at:
http://blackfin.uclinux.org/

We have tested this on LTP, and our test plan (including pass/fails) can
be found at:
http://docs.blackfin.uclinux.org/doku.php?id=testing_the_linux_kernel

[m.kozlowski@tuxland.pl: balance parenthesis in blackfin header files]
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: Aubrey Li <aubrey.li@analog.com>
Signed-off-by: Jie Zhang <jie.zhang@analog.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 394 insertions, 0 deletions

diff --git a/arch/blackfin/kernel/process.c b/arch/blackfin/kernel/process.c
new file mode 100644
index 000000000000..3eff7439d8d3
--- /dev/null
+++ b/arch/blackfin/kernel/process.c
@@ -0,0 +1,394 @@
+/*
+ * File:         arch/blackfin/kernel/process.c
+ * Based on:
+ * Author:
+ *
+ * Created:
+ * Description:  Blackfin architecture-dependent process handling.
+ *
+ * Modified:
+ *               Copyright 2004-2006 Analog Devices Inc.
+ *
+ * Bugs:         Enter bugs at http://blackfin.uclinux.org/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see the file COPYING, or write
+ * to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <linux/module.h>
+#include <linux/smp_lock.h>
+#include <linux/unistd.h>
+#include <linux/user.h>
+#include <linux/a.out.h>
+
+#include <asm/blackfin.h>
+#include <asm/uaccess.h>
+
+#define	LED_ON	0
+#define	LED_OFF	1
+
+asmlinkage void ret_from_fork(void);
+
+/* Points to the SDRAM backup memory for the stack that is currently in
+ * L1 scratchpad memory.
+ */
+void *current_l1_stack_save;
+
+/* The number of tasks currently using a L1 stack area.  The SRAM is
+ * allocated/deallocated whenever this changes from/to zero.
+ */
+int nr_l1stack_tasks;
+
+/* Start and length of the area in L1 scratchpad memory which we've allocated
+ * for process stacks.
+ */
+void *l1_stack_base;
+unsigned long l1_stack_len;
+
+/*
+ * Powermanagement idle function, if any..
+ */
+void (*pm_idle)(void) = NULL;
+EXPORT_SYMBOL(pm_idle);
+
+void (*pm_power_off)(void) = NULL;
+EXPORT_SYMBOL(pm_power_off);
+
+/*
+ * We are using a different LED from the one used to indicate timer interrupt.
+ */
+#if defined(CONFIG_BFIN_IDLE_LED)
+static inline void leds_switch(int flag)
+{
+	unsigned short tmp = 0;
+
+	tmp = bfin_read_CONFIG_BFIN_IDLE_LED_PORT();
+	SSYNC();
+
+	if (flag == LED_ON)
+		tmp &= ~CONFIG_BFIN_IDLE_LED_PIN;	/* light on */
+	else
+		tmp |= CONFIG_BFIN_IDLE_LED_PIN;	/* light off */
+
+	bfin_write_CONFIG_BFIN_IDLE_LED_PORT(tmp);
+	SSYNC();
+
+}
+#else
+static inline void leds_switch(int flag)
+{
+}
+#endif
+
+/*
+ * The idle loop on BFIN
+ */
+#ifdef CONFIG_IDLE_L1
+void default_idle(void)__attribute__((l1_text));
+void cpu_idle(void)__attribute__((l1_text));
+#endif
+
+void default_idle(void)
+{
+	while (!need_resched()) {
+		leds_switch(LED_OFF);
+		local_irq_disable();
+		if (likely(!need_resched()))
+			idle_with_irq_disabled();
+		local_irq_enable();
+		leds_switch(LED_ON);
+	}
+}
+
+void (*idle)(void) = default_idle;
+
+/*
+ * The idle thread. There's no useful work to be
+ * done, so just try to conserve power and have a
+ * low exit latency (ie sit in a loop waiting for
+ * somebody to say that they'd like to reschedule)
+ */
+void cpu_idle(void)
+{
+	/* endless idle loop with no priority at all */
+	while (1) {
+		idle();
+		preempt_enable_no_resched();
+		schedule();
+		preempt_disable();
+	}
+}
+
+void machine_restart(char *__unused)
+{
+#if defined(CONFIG_BLKFIN_CACHE)
+	bfin_write_IMEM_CONTROL(0x01);
+	SSYNC();
+#endif
+	bfin_reset();
+	/* Dont do anything till the reset occurs */
+	while (1) {
+		SSYNC();
+	}
+}
+
+void machine_halt(void)
+{
+	for (;;)
+		asm volatile ("idle");
+}
+
+void machine_power_off(void)
+{
+	for (;;)
+		asm volatile ("idle");
+}
+
+void show_regs(struct pt_regs *regs)
+{
+	printk(KERN_NOTICE "\n");
+	printk(KERN_NOTICE
+	       "PC: %08lu  Status: %04lu  SysStatus: %04lu  RETS: %08lu\n",
+	       regs->pc, regs->astat, regs->seqstat, regs->rets);
+	printk(KERN_NOTICE
+	       "A0.x: %08lx  A0.w: %08lx  A1.x: %08lx  A1.w: %08lx\n",
+	       regs->a0x, regs->a0w, regs->a1x, regs->a1w);
+	printk(KERN_NOTICE "P0: %08lx  P1: %08lx  P2: %08lx  P3: %08lx\n",
+	       regs->p0, regs->p1, regs->p2, regs->p3);
+	printk(KERN_NOTICE "P4: %08lx  P5: %08lx\n", regs->p4, regs->p5);
+	printk(KERN_NOTICE "R0: %08lx  R1: %08lx  R2: %08lx  R3: %08lx\n",
+	       regs->r0, regs->r1, regs->r2, regs->r3);
+	printk(KERN_NOTICE "R4: %08lx  R5: %08lx  R6: %08lx  R7: %08lx\n",
+	       regs->r4, regs->r5, regs->r6, regs->r7);
+
+	if (!(regs->ipend))
+		printk("USP: %08lx\n", rdusp());
+}
+
+/* Fill in the fpu structure for a core dump.  */
+
+int dump_fpu(struct pt_regs *regs, elf_fpregset_t * fpregs)
+{
+	return 1;
+}
+
+/*
+ * This gets run with P1 containing the
+ * function to call, and R1 containing
+ * the "args".  Note P0 is clobbered on the way here.
+ */
+void kernel_thread_helper(void);
+__asm__(".section .text\n"
+	".align 4\n"
+	"_kernel_thread_helper:\n\t"
+	"\tsp += -12;\n\t"
+	"\tr0 = r1;\n\t" "\tcall (p1);\n\t" "\tcall _do_exit;\n" ".previous");
+
+/*
+ * Create a kernel thread.
+ */
+pid_t kernel_thread(int (*fn) (void *), void *arg, unsigned long flags)
+{
+	struct pt_regs regs;
+
+	memset(&regs, 0, sizeof(regs));
+
+	regs.r1 = (unsigned long)arg;
+	regs.p1 = (unsigned long)fn;
+	regs.pc = (unsigned long)kernel_thread_helper;
+	regs.orig_p0 = -1;
+	/* Set bit 2 to tell ret_from_fork we should be returning to kernel
+	   mode.  */
+	regs.ipend = 0x8002;
+	__asm__ __volatile__("%0 = syscfg;":"=da"(regs.syscfg):);
+	return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL,
+		       NULL);
+}
+
+void flush_thread(void)
+{
+}
+
+asmlinkage int bfin_vfork(struct pt_regs *regs)
+{
+	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, NULL,
+		       NULL);
+}
+
+asmlinkage int bfin_clone(struct pt_regs *regs)
+{
+	unsigned long clone_flags;
+	unsigned long newsp;
+
+	/* syscall2 puts clone_flags in r0 and usp in r1 */
+	clone_flags = regs->r0;
+	newsp = regs->r1;
+	if (!newsp)
+		newsp = rdusp();
+	else
+		newsp -= 12;
+	return do_fork(clone_flags, newsp, regs, 0, NULL, NULL);
+}
+
+int
+copy_thread(int nr, unsigned long clone_flags,
+	    unsigned long usp, unsigned long topstk,
+	    struct task_struct *p, struct pt_regs *regs)
+{
+	struct pt_regs *childregs;
+
+	childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
+	*childregs = *regs;
+	childregs->r0 = 0;
+
+	p->thread.usp = usp;
+	p->thread.ksp = (unsigned long)childregs;
+	p->thread.pc = (unsigned long)ret_from_fork;
+
+	return 0;
+}
+
+/*
+ * fill in the user structure for a core dump..
+ */
+void dump_thread(struct pt_regs *regs, struct user *dump)
+{
+	dump->magic = CMAGIC;
+	dump->start_code = 0;
+	dump->start_stack = rdusp() & ~(PAGE_SIZE - 1);
+	dump->u_tsize = ((unsigned long)current->mm->end_code) >> PAGE_SHIFT;
+	dump->u_dsize = ((unsigned long)(current->mm->brk +
+					 (PAGE_SIZE - 1))) >> PAGE_SHIFT;
+	dump->u_dsize -= dump->u_tsize;
+	dump->u_ssize = 0;
+
+	if (dump->start_stack < TASK_SIZE)
+		dump->u_ssize =
+		    ((unsigned long)(TASK_SIZE -
+				     dump->start_stack)) >> PAGE_SHIFT;
+
+	dump->u_ar0 = (struct user_regs_struct *)((int)&dump->regs - (int)dump);
+
+	dump->regs.r0 = regs->r0;
+	dump->regs.r1 = regs->r1;
+	dump->regs.r2 = regs->r2;
+	dump->regs.r3 = regs->r3;
+	dump->regs.r4 = regs->r4;
+	dump->regs.r5 = regs->r5;
+	dump->regs.r6 = regs->r6;
+	dump->regs.r7 = regs->r7;
+	dump->regs.p0 = regs->p0;
+	dump->regs.p1 = regs->p1;
+	dump->regs.p2 = regs->p2;
+	dump->regs.p3 = regs->p3;
+	dump->regs.p4 = regs->p4;
+	dump->regs.p5 = regs->p5;
+	dump->regs.orig_p0 = regs->orig_p0;
+	dump->regs.a0w = regs->a0w;
+	dump->regs.a1w = regs->a1w;
+	dump->regs.a0x = regs->a0x;
+	dump->regs.a1x = regs->a1x;
+	dump->regs.rets = regs->rets;
+	dump->regs.astat = regs->astat;
+	dump->regs.pc = regs->pc;
+}
+
+/*
+ * sys_execve() executes a new program.
+ */
+
+asmlinkage int sys_execve(char *name, char **argv, char **envp)
+{
+	int error;
+	char *filename;
+	struct pt_regs *regs = (struct pt_regs *)((&name) + 6);
+
+	lock_kernel();
+	filename = getname(name);
+	error = PTR_ERR(filename);
+	if (IS_ERR(filename))
+		goto out;
+	error = do_execve(filename, argv, envp, regs);
+	putname(filename);
+      out:
+	unlock_kernel();
+	return error;
+}
+
+unsigned long get_wchan(struct task_struct *p)
+{
+	unsigned long fp, pc;
+	unsigned long stack_page;
+	int count = 0;
+	if (!p || p == current || p->state == TASK_RUNNING)
+		return 0;
+
+	stack_page = (unsigned long)p;
+	fp = p->thread.usp;
+	do {
+		if (fp < stack_page + sizeof(struct thread_info) ||
+		    fp >= 8184 + stack_page)
+			return 0;
+		pc = ((unsigned long *)fp)[1];
+		if (!in_sched_functions(pc))
+			return pc;
+		fp = *(unsigned long *)fp;
+	}
+	while (count++ < 16);
+	return 0;
+}
+
+#if defined(CONFIG_ACCESS_CHECK)
+int _access_ok(unsigned long addr, unsigned long size)
+{
+
+	if (addr > (addr + size))
+		return 0;
+	if (segment_eq(get_fs(),KERNEL_DS))
+		return 1;
+#ifdef CONFIG_MTD_UCLINUX
+	if (addr >= memory_start && (addr + size) <= memory_end)
+		return 1;
+	if (addr >= memory_mtd_end && (addr + size) <= physical_mem_end)
+		return 1;
+#else
+	if (addr >= memory_start && (addr + size) <= physical_mem_end)
+		return 1;
+#endif
+	if (addr >= (unsigned long)__init_begin &&
+	    addr + size <= (unsigned long)__init_end)
+		return 1;
+	if (addr >= L1_SCRATCH_START
+	    && addr + size <= L1_SCRATCH_START + L1_SCRATCH_LENGTH)
+		return 1;
+#if L1_CODE_LENGTH != 0
+	if (addr >= L1_CODE_START + (_etext_l1 - _stext_l1)
+	    && addr + size <= L1_CODE_START + L1_CODE_LENGTH)
+		return 1;
+#endif
+#if L1_DATA_A_LENGTH != 0
+	if (addr >= L1_DATA_A_START + (_ebss_l1 - _sdata_l1)
+	    && addr + size <= L1_DATA_A_START + L1_DATA_A_LENGTH)
+		return 1;
+#endif
+#if L1_DATA_B_LENGTH != 0
+	if (addr >= L1_DATA_B_START
+	    && addr + size <= L1_DATA_B_START + L1_DATA_B_LENGTH)
+		return 1;
+#endif
+	return 0;
+}
+EXPORT_SYMBOL(_access_ok);
+#endif /* CONFIG_ACCESS_CHECK */