Hexagon: Add startup code

/*

 * Early kernel startup code for Hexagon

 *

 * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.

 *

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and

 * only version 2 as published by the Free Software Foundation.

 *

 * 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, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA.

 */

#include <linux/linkage.h>

#include <linux/init.h>

#include <asm/asm-offsets.h>

#include <asm/mem-layout.h>

#include <asm/vm_mmu.h>

#include <asm/page.h>

	__INIT

ENTRY(stext)

	/*

	 * VMM will already have set up true vector page, MMU, etc.

	 * To set up initial kernel identity map, we have to pass

	 * the VMM a pointer to some canonical page tables. In

	 * this implementation, we're assuming that we've got

	 * them precompiled. Generate value in R24, as we'll need

	 * it again shortly.

	 */

	r24.L = #LO(swapper_pg_dir)

	r24.H = #HI(swapper_pg_dir)

	/*

	 * Symbol is kernel segment address, but we need

	 * the logical/physical address.

	 */

	r24 = asl(r24, #2)

	r24 = lsr(r24, #2)

	r0 = r24

	/*

	 * Initialize a 16MB PTE to make the virtual and physical

	 * addresses where the kernel was loaded be identical.

	 */

#define PTE_BITS ( __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X	\

		  | __HEXAGON_C_WB_L2 << 6			\

		  | __HVM_PDE_S_4MB)

	r1 = pc

	r2.H = #0xffc0

	r2.L = #0x0000

	r1 = and(r1,r2)		/* round PC to 4MB boundary	*/

	r2 = lsr(r1, #22)	/* 4MB page number		*/

	r2 = asl(r2, #2)	/* times sizeof(PTE) (4bytes)	*/

	r0 = add(r0,r2)		/* r0 = address of correct PTE	*/

	r2 = #PTE_BITS

	r1 = add(r1,r2)		/* r1 = 4MB PTE for the first entry	*/

	r2.h = #0x0040

	r2.l = #0x0000		/* 4MB	*/

	memw(r0 ++ #4) = r1

	r1 = add(r1, r2)

	memw(r0 ++ #4) = r1

	r0 = r24

	/*

	 * The subroutine wrapper around the virtual instruction touches

	 * no memory, so we should be able to use it even here.

	 */

	call	__vmnewmap;

	/*  Jump into virtual address range.  */

	r31.h = #hi(__head_s_vaddr_target)

	r31.l = #lo(__head_s_vaddr_target)

	jumpr r31

	/*  Insert trippy space effects.  */

__head_s_vaddr_target:

	/*

	 * Tear down VA=PA translation now that we are running

	 * in the desgnated kernel segments.

	 */

	r0 = #__HVM_PDE_S_INVALID

	r1 = r24

	loop0(1f,#0x100)

1:

	{

		memw(R1 ++ #4) = R0

	}:endloop0

	r0 = r24

	call __vmnewmap

	/*  Go ahead and install the trap0 return so angel calls work  */

	r0.h = #hi(_K_provisional_vec)

	r0.l = #lo(_K_provisional_vec)

	call __vmsetvec

	/*

	 * OK, at this point we should start to be much more careful,

	 * we're going to enter C code and start touching memory

	 * in all sorts of places.

	 * This means:

	 *      SGP needs to be OK

	 *	Need to lock shared resources

	 *	A bunch of other things that will cause

	 * 	all kinds of painful bugs

	 */

	/*

	 * Stack pointer should be pointed at the init task's

	 * thread stack, which should have been declared in arch/init_task.c.

	 * So uhhhhh...

	 * It's accessible via the init_thread_union, which is a union

	 * of a thread_info struct and a stack; of course, the top

	 * of the stack is not for you.  The end of the stack

	 * is simply init_thread_union + THREAD_SIZE.

	 */

	{r29.H = #HI(init_thread_union); r0.H = #HI(_THREAD_SIZE); }

	{r29.L = #LO(init_thread_union); r0.L = #LO(_THREAD_SIZE); }

	/*  initialize the register used to point to current_thread_info */

	/*  Fixme:  THREADINFO_REG can't be R2 because of that memset thing. */

	{r29 = add(r29,r0); THREADINFO_REG = r29; }

	/*  Hack:  zero bss; */

	{ r0.L = #LO(__bss_start);  r1 = #0; r2.l = #LO(__bss_stop); }

	{ r0.H = #HI(__bss_start);           r2.h = #HI(__bss_stop); }

	r2 = sub(r2,r0);

	call memset;

	/* Time to make the doughnuts.   */

	call start_kernel

	/*

	 * Should not reach here.

	 */

1:

	jump 1b

.p2align PAGE_SHIFT

ENTRY(external_cmdline_buffer)

        .fill _PAGE_SIZE,1,0

.data

.p2align PAGE_SHIFT

ENTRY(empty_zero_page)

        .fill _PAGE_SIZE,1,0

/*

 * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and

 * only version 2 as published by the Free Software Foundation.

 *

 * 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, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA.

 */

#include <linux/smp.h>

#include <asm/hexagon_vm.h>

void machine_power_off(void)

{

	smp_send_stop();

	__vmstop();

}

void machine_halt(void)

{

}

void machine_restart(char *cmd)

{

}

void pm_power_off(void)

{

}

/*

 * Arch related setup for Hexagon

 *

 * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and

 * only version 2 as published by the Free Software Foundation.

 *

 * 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, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA.

 */

#include <linux/init.h>

#include <linux/bootmem.h>

#include <linux/mmzone.h>

#include <linux/mm.h>

#include <linux/seq_file.h>

#include <linux/console.h>

#include <linux/of_fdt.h>

#include <asm/io.h>

#include <asm/sections.h>

#include <asm/setup.h>

#include <asm/processor.h>

#include <asm/hexagon_vm.h>

#include <asm/vm_mmu.h>

#include <asm/time.h>

#ifdef CONFIG_OF

#include <asm/prom.h>

#endif

char cmd_line[COMMAND_LINE_SIZE];

static char default_command_line[COMMAND_LINE_SIZE] __initdata = CONFIG_CMDLINE;

int on_simulator;

void __cpuinit calibrate_delay(void)

{

	loops_per_jiffy = thread_freq_mhz * 1000000 / HZ;

}

/*

 * setup_arch -  high level architectural setup routine

 * @cmdline_p: pointer to pointer to command-line arguments

 */

void __init setup_arch(char **cmdline_p)

{

	char *p = &external_cmdline_buffer;

	/*

	 * These will eventually be pulled in via either some hypervisor

	 * or devicetree description.  Hardwiring for now.

	 */

	pcycle_freq_mhz = 600;

	thread_freq_mhz = 100;

	sleep_clk_freq = 32000;

	/*

	 * Set up event bindings to handle exceptions and interrupts.

	 */

	__vmsetvec(_K_VM_event_vector);

	/*

	 * Simulator has a few differences from the hardware.

	 * For now, check uninitialized-but-mapped memory

	 * prior to invoking setup_arch_memory().

	 */

	if (*(int *)((unsigned long)_end + 8) == 0x1f1f1f1f)

		on_simulator = 1;

	else

		on_simulator = 0;

	if (p[0] != '\0')

		strlcpy(boot_command_line, p, COMMAND_LINE_SIZE);

	else

		strlcpy(boot_command_line, default_command_line,

			COMMAND_LINE_SIZE);

	/*

	 * boot_command_line and the value set up by setup_arch

	 * are both picked up by the init code. If no reason to

	 * make them different, pass the same pointer back.

	 */

	strlcpy(cmd_line, boot_command_line, COMMAND_LINE_SIZE);

	*cmdline_p = cmd_line;

	parse_early_param();

	setup_arch_memory();

#ifdef CONFIG_SMP

	smp_start_cpus();

#endif

}

/*

 * Functions for dumping CPU info via /proc

 * Probably should move to kernel/proc.c or something.

 */

static void *c_start(struct seq_file *m, loff_t *pos)

{

	return *pos < nr_cpu_ids ? (void *)((unsigned long) *pos + 1) : NULL;

}

static void *c_next(struct seq_file *m, void *v, loff_t *pos)

{

	++*pos;

	return c_start(m, pos);

}

static void c_stop(struct seq_file *m, void *v)

{

}

/*

 * Eventually this will dump information about

 * CPU properties like ISA level, TLB size, etc.

 */

static int show_cpuinfo(struct seq_file *m, void *v)

{

	int cpu = (unsigned long) v - 1;

	seq_printf(m, "processor\t: %d\n", cpu);

	seq_printf(m, "model name\t: Hexagon Virtual Machine\n");

	seq_printf(m, "BogoMips\t: %lu.%02lu\n",

		(loops_per_jiffy * HZ) / 500000,

		((loops_per_jiffy * HZ) / 5000) % 100);

	seq_printf(m, "\n");

	return 0;

}

const struct seq_operations cpuinfo_op = {

	.start  = &c_start,

	.next   = &c_next,

	.stop   = &c_stop,

	.show   = &show_cpuinfo,

};