Commit 93d39210 authored by Cédric Le Goater's avatar Cédric Le Goater Committed by Benjamin Herrenschmidt
Browse files

powerpc/boot: Define a routine to enter prom 



This patch defines a 'prom' routine similar to 'enter_prom' in the
kernel.

The difference is in the MSR which is built before entering prom. Big
endian order is enforced as in the kernel but 32bit mode is not. It
prepares ground for the next patches which will introduce Little endian
order.

Signed-off-by: default avatarCédric Le Goater <clg@fr.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 002c39db

arch/powerpc/boot/crt0.S

+71 −0
Original line number Diff line number Diff line
@@ -126,3 +126,74 @@ RELACOUNT = 0x6ffffff9 


	/* Call start */

	b	start



#ifdef __powerpc64__



#define PROM_FRAME_SIZE 512

#define SAVE_GPR(n, base)       std     n,8*(n)(base)

#define REST_GPR(n, base)       ld      n,8*(n)(base)

#define SAVE_2GPRS(n, base)     SAVE_GPR(n, base); SAVE_GPR(n+1, base)

#define SAVE_4GPRS(n, base)     SAVE_2GPRS(n, base); SAVE_2GPRS(n+2, base)

#define SAVE_8GPRS(n, base)     SAVE_4GPRS(n, base); SAVE_4GPRS(n+4, base)

#define SAVE_10GPRS(n, base)    SAVE_8GPRS(n, base); SAVE_2GPRS(n+8, base)

#define REST_2GPRS(n, base)     REST_GPR(n, base); REST_GPR(n+1, base)

#define REST_4GPRS(n, base)     REST_2GPRS(n, base); REST_2GPRS(n+2, base)

#define REST_8GPRS(n, base)     REST_4GPRS(n, base); REST_4GPRS(n+4, base)

#define REST_10GPRS(n, base)    REST_8GPRS(n, base); REST_2GPRS(n+8, base)



/* prom handles the jump into and return from firmware.  The prom args pointer

   is loaded in r3. */

.globl prom

prom:

	mflr	r0

	std	r0,16(r1)

	stdu	r1,-PROM_FRAME_SIZE(r1) /* Save SP and create stack space */



	SAVE_GPR(2, r1)

	SAVE_GPR(13, r1)

	SAVE_8GPRS(14, r1)

	SAVE_10GPRS(22, r1)

	mfcr    r10

	std     r10,8*32(r1)

	mfmsr   r10

	std     r10,8*33(r1)



	/* remove MSR_LE from msr but keep MSR_SF */

	mfmsr	r10

	rldicr	r10,r10,0,62

	mtsrr1	r10



	/* Load FW address, set LR to label 1, and jump to FW */

	bl	0f

0:	mflr	r10

	addi	r11,r10,(1f-0b)

	mtlr	r11



	ld	r10,(p_prom-0b)(r10)

	mtsrr0	r10



	rfid



1:	/* Return from OF */



	/* Restore registers and return. */

	rldicl  r1,r1,0,32



	/* Restore the MSR (back to 64 bits) */

	ld      r10,8*(33)(r1)

	mtmsr	r10

	isync



	/* Restore other registers */

	REST_GPR(2, r1)

	REST_GPR(13, r1)

	REST_8GPRS(14, r1)

	REST_10GPRS(22, r1)

	ld      r10,8*32(r1)

	mtcr	r10



	addi    r1,r1,PROM_FRAME_SIZE

	ld      r0,16(r1)

	mtlr    r0

	blr

#endif

arch/powerpc/boot/oflib.c

+6 −0
Original line number Diff line number Diff line
@@ -27,11 +27,17 @@ struct prom_args { 
	__be32 args[10];	/* Input/output arguments. */

};



#ifdef __powerpc64__

extern int prom(void *);

#else

static int (*prom) (void *);

#endif



void of_init(void *promptr)

{

#ifndef __powerpc64__

	prom = (int (*)(void *))promptr;

#endif

}



#define ADDR(x)		(u32)(unsigned long)(x)

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