head.S

/*
 * File:         arch/blackfin/mach-bf548/head.S
 * Based on:     arch/blackfin/mach-bf537/head.S
 * Author:       Jeff Dionne <jeff@uclinux.org> COPYRIGHT 1998 D. Jeff Dionne
 *
 * Created:      1998
 * Description:  Startup code for Blackfin BF548
 *
 * Modified:
 *               Copyright 2004-2007 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/linkage.h>
#include <asm/blackfin.h>
#include <asm/trace.h>
#if CONFIG_BFIN_KERNEL_CLOCK
#include <asm/mach-common/clocks.h>
#include <asm/mach/mem_init.h>
#endif

.global __rambase
.global __ramstart
.global __ramend
.extern ___bss_stop
.extern ___bss_start
.extern _bf53x_relocate_l1_mem

#define INITIAL_STACK   0xFFB01000

.text

ENTRY(__start)
ENTRY(__stext)
	/* R0: argument of command line string, passed from uboot, save it */
	R7 = R0;
	/* Enable Cycle Counter and Nesting Of Interrupts */
#ifdef CONFIG_BFIN_SCRATCH_REG_CYCLES
	R0 = SYSCFG_SNEN;
#else
	R0 = SYSCFG_SNEN | SYSCFG_CCEN;
#endif
	SYSCFG = R0;
	R0 = 0;

	/* Clear Out All the data and pointer  Registers*/
	R1 = R0;
	R2 = R0;
	R3 = R0;
	R4 = R0;
	R5 = R0;
	R6 = R0;

	P0 = R0;
	P1 = R0;
	P2 = R0;
	P3 = R0;
	P4 = R0;
	P5 = R0;

	LC0 = r0;
	LC1 = r0;
	L0 = r0;
	L1 = r0;
	L2 = r0;
	L3 = r0;

	/* Clear Out All the DAG Registers*/
	B0 = r0;
	B1 = r0;
	B2 = r0;
	B3 = r0;

	I0 = r0;
	I1 = r0;
	I2 = r0;
	I3 = r0;

	M0 = r0;
	M1 = r0;
	M2 = r0;
	M3 = r0;

	trace_buffer_init(p0,r0);
	P0 = R1;
	R0 = R1;

	/* Turn off the icache */
	p0.l = LO(IMEM_CONTROL);
	p0.h = HI(IMEM_CONTROL);
	R1 = [p0];
	R0 = ~ENICPLB;
	R0 = R0 & R1;
	[p0] = R0;
	SSYNC;

	/* Turn off the dcache */
	p0.l = LO(DMEM_CONTROL);
	p0.h = HI(DMEM_CONTROL);
	R1 = [p0];
	R0 = ~ENDCPLB;
	R0 = R0 & R1;
	[p0] = R0;
	SSYNC;

	/* Initialize stack pointer */
	SP.L = LO(INITIAL_STACK);
	SP.H = HI(INITIAL_STACK);
	FP = SP;
	USP = SP;

#ifdef CONFIG_EARLY_PRINTK
	SP += -12;
	call _init_early_exception_vectors;
	SP += 12;
#endif

	/* Put The Code for PLL Programming and SDRAM Programming in L1 ISRAM */
	call _bf53x_relocate_l1_mem;
#if CONFIG_BFIN_KERNEL_CLOCK
	call _start_dma_code;
#endif
	/* Code for initializing Async memory banks */

	p2.h = hi(EBIU_AMBCTL1);
	p2.l = lo(EBIU_AMBCTL1);
	r0.h = hi(AMBCTL1VAL);
	r0.l = lo(AMBCTL1VAL);
	[p2] = r0;
	ssync;

	p2.h = hi(EBIU_AMBCTL0);
	p2.l = lo(EBIU_AMBCTL0);
	r0.h = hi(AMBCTL0VAL);
	r0.l = lo(AMBCTL0VAL);
	[p2] = r0;
	ssync;

	p2.h = hi(EBIU_AMGCTL);
	p2.l = lo(EBIU_AMGCTL);
	r0 = AMGCTLVAL;
	w[p2] = r0;
	ssync;

	p2.h = hi(EBIU_MBSCTL);
	p2.l = lo(EBIU_MBSCTL);
	r0.h = hi(CONFIG_EBIU_MBSCTLVAL);
	r0.l = lo(CONFIG_EBIU_MBSCTLVAL);
	[p2] = r0;
	ssync;

	p2.h = hi(EBIU_MODE);
	p2.l = lo(EBIU_MODE);
	r0.h = hi(CONFIG_EBIU_MODEVAL);
	r0.l = lo(CONFIG_EBIU_MODEVAL);
	[p2] = r0;
	ssync;

	p2.h = hi(EBIU_FCTL);
	p2.l = lo(EBIU_FCTL);
	r0.h = hi(CONFIG_EBIU_FCTLVAL);
	r0.l = lo(CONFIG_EBIU_FCTLVAL);
	[p2] = r0;
	ssync;

	/* This section keeps the processor in supervisor mode
	 * during kernel boot.  Switches to user mode at end of boot.
	 * See page 3-9 of Hardware Reference manual for documentation.
	 */

	/* EVT15 = _real_start */

	p0.l = lo(EVT15);
	p0.h = hi(EVT15);
	p1.l = _real_start;
	p1.h = _real_start;
	[p0] = p1;
	csync;

	p0.l = lo(IMASK);
	p0.h = hi(IMASK);
	p1.l = IMASK_IVG15;
	p1.h = 0x0;
	[p0] = p1;
	csync;

	raise 15;
	p0.l = .LWAIT_HERE;
	p0.h = .LWAIT_HERE;
	reti = p0;
#if ANOMALY_05000281
	nop;
	nop;
	nop;
#endif
	rti;

.LWAIT_HERE:
	jump .LWAIT_HERE;

ENTRY(_real_start)
	[ -- sp ] = reti;
	p0.l = lo(WDOG_CTL);
	p0.h = hi(WDOG_CTL);
	r0 = 0xAD6(z);
	w[p0] = r0;	/* watchdog off for now */
	ssync;

	/* Code update for BSS size == 0
	 * Zero out the bss region.
	 */

	p1.l = ___bss_start;
	p1.h = ___bss_start;
	p2.l = ___bss_stop;
	p2.h = ___bss_stop;
	r0 = 0;
	p2 -= p1;
	lsetup (.L_clear_bss, .L_clear_bss ) lc0 = p2;
.L_clear_bss:
	B[p1++] = r0;

	/* In case there is a NULL pointer reference
	 * Zero out region before stext
	 */

	p1.l = 0x0;
	p1.h = 0x0;
	r0.l = __stext;
	r0.h = __stext;
	r0 = r0 >> 1;
	p2 = r0;
	r0 = 0;
	lsetup (.L_clear_zero, .L_clear_zero ) lc0 = p2;
.L_clear_zero:
	W[p1++] = r0;

	/* pass the uboot arguments to the global value command line */
	R0 = R7;
	call _cmdline_init;

	p1.l = __rambase;
	p1.h = __rambase;
	r0.l = __sdata;
	r0.h = __sdata;
	[p1] = r0;

	p1.l = __ramstart;
	p1.h = __ramstart;
	p3.l = ___bss_stop;
	p3.h = ___bss_stop;

	r1 = p3;
	[p1] = r1;


	/*
	 *  load the current thread pointer and stack
	 */
	r1.l = _init_thread_union;
	r1.h = _init_thread_union;

	r2.l = 0x2000;
	r2.h = 0x0000;
	r1 = r1 + r2;
	sp = r1;
	usp = sp;
	fp = sp;
	call _start_kernel;
.L_exit:
	jump.s	.L_exit;

.section .l1.text
#if CONFIG_BFIN_KERNEL_CLOCK
ENTRY(_start_dma_code)

	/* Enable PHY CLK buffer output */
	p0.h = hi(VR_CTL);
	p0.l = lo(VR_CTL);
	r0.l = w[p0];
	bitset(r0, 14);
	w[p0] = r0.l;
	ssync;

	p0.h = hi(SIC_IWR);
	p0.l = lo(SIC_IWR);
	r0.l = 0x1;
	r0.h = 0x0;
	[p0] = r0;
	SSYNC;

	/*
	 *  Set PLL_CTL
	 *   - [14:09] = MSEL[5:0] : CLKIN / VCO multiplication factors
	 *   - [8]     = BYPASS    : BYPASS the PLL, run CLKIN into CCLK/SCLK
	 *   - [7]     = output delay (add 200ps of delay to mem signals)
	 *   - [6]     = input delay (add 200ps of input delay to mem signals)
	 *   - [5]     = PDWN      : 1=All Clocks off
	 *   - [3]     = STOPCK    : 1=Core Clock off
	 *   - [1]     = PLL_OFF   : 1=Disable Power to PLL
	 *   - [0]     = DF        : 1=Pass CLKIN/2 to PLL / 0=Pass CLKIN to PLL
	 *   all other bits set to zero
	 */

	p0.h = hi(PLL_LOCKCNT);
	p0.l = lo(PLL_LOCKCNT);
	r0 = 0x300(Z);
	w[p0] = r0.l;
	ssync;

	P2.H = hi(EBIU_SDGCTL);
	P2.L = lo(EBIU_SDGCTL);
	R0 = [P2];
	BITSET (R0, 24);
	[P2] = R0;
	SSYNC;

	r0 = CONFIG_VCO_MULT & 63;       /* Load the VCO multiplier         */
	r0 = r0 << 9;                    /* Shift it over,                  */
	r1 = CLKIN_HALF;                 /* Do we need to divide CLKIN by 2?*/
	r0 = r1 | r0;
	r1 = PLL_BYPASS;                 /* Bypass the PLL?                 */
	r1 = r1 << 8;                    /* Shift it over                   */
	r0 = r1 | r0;                    /* add them all together           */

	p0.h = hi(PLL_CTL);
	p0.l = lo(PLL_CTL);              /* Load the address                */
	cli r2;                          /* Disable interrupts              */
	ssync;
	w[p0] = r0.l;                    /* Set the value                   */
	idle;                            /* Wait for the PLL to stablize    */
	sti r2;                          /* Enable interrupts               */

.Lcheck_again:
	p0.h = hi(PLL_STAT);
	p0.l = lo(PLL_STAT);
	R0 = W[P0](Z);
	CC = BITTST(R0,5);
	if ! CC jump .Lcheck_again;

	/* Configure SCLK & CCLK Dividers */
	r0 = (CONFIG_CCLK_ACT_DIV | CONFIG_SCLK_DIV);
	p0.h = hi(PLL_DIV);
	p0.l = lo(PLL_DIV);
	w[p0] = r0.l;
	ssync;

	p0.l = lo(EBIU_SDRRC);
	p0.h = hi(EBIU_SDRRC);
	r0 = mem_SDRRC;
	w[p0] = r0.l;
	ssync;

	p0.l = LO(EBIU_SDBCTL);
	p0.h = HI(EBIU_SDBCTL);     /* SDRAM Memory Bank Control Register */
	r0 = mem_SDBCTL;
	w[p0] = r0.l;
	ssync;

	P2.H = hi(EBIU_SDGCTL);
	P2.L = lo(EBIU_SDGCTL);
	R0 = [P2];
	BITCLR (R0, 24);
	p0.h = hi(EBIU_SDSTAT);
	p0.l = lo(EBIU_SDSTAT);
	r2.l = w[p0];
	cc = bittst(r2,3);
	if !cc jump .Lskip;
	NOP;
	BITSET (R0, 23);
.Lskip:
	[P2] = R0;
	SSYNC;

	R0.L = lo(mem_SDGCTL);
	R0.H = hi(mem_SDGCTL);
	R1 = [p2];
	R1 = R1 | R0;
	[P2] = R1;
	SSYNC;

	p0.h = hi(SIC_IWR);
	p0.l = lo(SIC_IWR);
	r0.l = lo(IWR_ENABLE_ALL);
	r0.h = hi(IWR_ENABLE_ALL);
	[p0] = r0;
	SSYNC;

	RTS;
#endif /* CONFIG_BFIN_KERNEL_CLOCK */

.data

/*
 * Set up the usable of RAM stuff. Size of RAM is determined then
 * an initial stack set up at the end.
 */

.align 4
__rambase:
.long   0
__ramstart:
.long   0
__ramend:
.long   0