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Commit 511cdcc5 authored by Mike Frysinger's avatar Mike Frysinger
Browse files

Blackfin: optimize startup code 



Take advantage of more Blackfin-specific insns, and only initialize
registers required by the ABI.

Signed-off-by: default avatarMike Frysinger <vapier@gentoo.org>
parent c6345ab1

arch/blackfin/mach-common/head.S

+41 −69
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ ENDPROC(__init_clear_bss) 
ENTRY(__start)

	/* 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;
@@ -38,76 +39,49 @@ ENTRY(__start) 
	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;



	/* Optimization register tricks: keep a base value in the

	 * reserved P registers so we use the load/store with an

	 * offset syntax.  R0 = [P5 + <constant>];

	 *   P5 - core MMR base

	 *   R6 - 0

	 */

	r6 = 0;

	p5.l = 0;

	p5.h = hi(COREMMR_BASE);



	/* Zero out registers required by Blackfin ABI */



	/* Disable circular buffers */

	L0 = r6;

	L1 = r6;

	L2 = r6;

	L3 = r6;



	/* Disable hardware loops in case we were started by 'go' */

	LC0 = r6;

	LC1 = r6;



	/*

	 * Clear ITEST_COMMAND and DTEST_COMMAND registers,

	 * Leaving these as non-zero can confuse the emulator

	 */

	p0.L = LO(DTEST_COMMAND);

	p0.H = HI(DTEST_COMMAND);

	[p0] = R0;

	[p0 + (ITEST_COMMAND - DTEST_COMMAND)] = R0;

	[p5 + (DTEST_COMMAND - COREMMR_BASE)] = r6;

	[p5 + (ITEST_COMMAND - COREMMR_BASE)] = r6;

	CSYNC;



	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;

	r1 = [p5 + (IMEM_CONTROL - COREMMR_BASE)];

	BITCLR (r1, ENICPLB_P);

	[p5 + (IMEM_CONTROL - COREMMR_BASE)] = r1;

	SSYNC;



	/* Turn off the dcache */

	p0.l = LO(DMEM_CONTROL);

	p0.h = HI(DMEM_CONTROL);

	R1 = [p0];

	R0 = ~ENDCPLB;

	R0 = R0 & R1;

	[p0] = R0;

	r1 = [p5 + (DMEM_CONTROL - COREMMR_BASE)];

	BITCLR (r1, ENDCPLB_P);

	[p5 + (DMEM_CONTROL - COREMMR_BASE)] = r1;

	SSYNC;



	/* in case of double faults, save a few things */
@@ -122,25 +96,25 @@ ENTRY(__start) 
	 * below

	 */

	GET_PDA(p0, r0);

	r6 = [p0 + PDA_DF_RETX];

	r5 = [p0 + PDA_DF_RETX];

	p1.l = _init_saved_retx;

	p1.h = _init_saved_retx;

	[p1] = r6;

	[p1] = r5;



	r6 = [p0 + PDA_DF_DCPLB];

	r5 = [p0 + PDA_DF_DCPLB];

	p1.l = _init_saved_dcplb_fault_addr;

	p1.h = _init_saved_dcplb_fault_addr;

	[p1] = r6;

	[p1] = r5;



	r6 = [p0 + PDA_DF_ICPLB];

	r5 = [p0 + PDA_DF_ICPLB];

	p1.l = _init_saved_icplb_fault_addr;

	p1.h = _init_saved_icplb_fault_addr;

	[p1] = r6;

	[p1] = r5;



	r6 = [p0 + PDA_DF_SEQSTAT];

	r5 = [p0 + PDA_DF_SEQSTAT];

	p1.l = _init_saved_seqstat;

	p1.h = _init_saved_seqstat;

	[p1] = r6;

	[p1] = r5;

#endif



	/* Initialize stack pointer */
@@ -155,7 +129,7 @@ ENTRY(__start) 
	sti r0;

#endif



	r0 = 0 (x);

	r0 = r6;

	/* Zero out all of the fun bss regions */

#if L1_DATA_A_LENGTH > 0

	r1.l = __sbss_l1;
@@ -210,11 +184,9 @@ ENTRY(__start) 


	/* EVT15 = _real_start */



	p0.l = lo(EVT15);

	p0.h = hi(EVT15);

	p1.l = _real_start;

	p1.h = _real_start;

	[p0] = p1;

	[p5 + (EVT15 - COREMMR_BASE)] = p1;

	csync;



#ifdef CONFIG_EARLY_PRINTK