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Commit 7b372d65 authored by Sam Ravnborg's avatar Sam Ravnborg Committed by David S. Miller
Browse files

sparc32: implement proper LEON support in head_32 (before highmem) 



Use PSR to check if the CPU is LEON and jump to
LEON specific code in this case.

Added a few constants to psr.h to increase readability.

Signed-off-by: default avatarSam Ravnborg <sam@ravnborg.org>
Cc: Daniel Hellstrom <daniel@gaisler.com>
Cc: Konrad Eisele <konrad@gaisler.com>
parent ec24158e

arch/sparc/include/asm/psr.h

+6 −0
Original line number Diff line number Diff line
@@ -35,6 +35,12 @@ 
#define PSR_VERS    0x0f000000         /* cpu-version field          */

#define PSR_IMPL    0xf0000000         /* cpu-implementation field   */



#define PSR_IMPL_SHIFT		28

#define PSR_IMPL_SHIFTED_MASK	0xf



#define PSR_IMPL_TI		0x4

#define PSR_IMPL_LEON		0xf



#ifdef __KERNEL__



#ifndef __ASSEMBLY__

arch/sparc/kernel/head_32.S

+47 −11
Original line number Diff line number Diff line
@@ -192,7 +192,7 @@ copy_prom_done: 
		bne	not_a_sun4

		 nop



halt_sun4_or_sun4c:

halt_notsup:

		ld	[%g7 + 0x68], %o1

		set	notsup, %o0

		sub	%o0, %l6, %o0
@@ -202,18 +202,31 @@ halt_sun4_or_sun4c: 
		 nop



not_a_sun4:

		/* It looks like this is a machine we support.

		 * Now find out what MMU we are dealing with

		 * LEON - identified by the psr.impl field

		 * Viking - identified by the psr.impl field

		 * In all other cases a sun4m srmmu.

		 * We check that the MMU is enabled in all cases.

		 */



		/* Check if this is a LEON CPU */

		rd	%psr, %g3

		srl	%g3, PSR_IMPL_SHIFT, %g3

		and	%g3, PSR_IMPL_SHIFTED_MASK, %g3

		cmp	%g3, PSR_IMPL_LEON

		be	leon_remap		/* It is a LEON - jump */

		 nop



		/* Sanity-check, is MMU enabled */

		lda	[%g0] ASI_M_MMUREGS, %g1

		andcc	%g1, 1, %g0

		be	halt_sun4_or_sun4c

		be	halt_notsup

		 nop



srmmu_remap:

		/* First, check for a viking (TI) module. */

		set	0x40000000, %g2

		rd	%psr, %g3

		and	%g2, %g3, %g3

		subcc	%g3, 0x0, %g0

		bz	srmmu_nviking

		/* Check for a viking (TI) module. */

		cmp	%g3, PSR_IMPL_TI

		bne	srmmu_not_viking

		 nop



		/* Figure out what kind of viking we are on.
@@ -228,7 +241,7 @@ srmmu_remap: 
		lda	[%g0] ASI_M_MMUREGS, %g3	! peek in the control reg

		and	%g2, %g3, %g3

		subcc	%g3, 0x0, %g0

		bnz	srmmu_nviking			! is in mbus mode

		bnz	srmmu_not_viking			! is in mbus mode

		 nop



		rd	%psr, %g3			! DO NOT TOUCH %g3
@@ -293,12 +306,12 @@ srmmu_remap: 
		b	go_to_highmem

		 nop



srmmu_not_viking:

		/* This works on viking's in Mbus mode and all

		 * other MBUS modules.  It is virtually the same as

		 * the above madness sans turning traps off and flipping

		 * the AC bit.

		 */

srmmu_nviking:

		set	AC_M_CTPR, %g1

		lda	[%g1] ASI_M_MMUREGS, %g1	! get ctx table ptr

		sll	%g1, 0x4, %g1			! make physical addr
@@ -313,6 +326,29 @@ srmmu_nviking: 
		 nop					! wheee....





leon_remap:

		/* Sanity-check, is MMU enabled */

		lda	[%g0] ASI_LEON_MMUREGS, %g1

		andcc	%g1, 1, %g0

		be	halt_notsup

		 nop



		/* Same code as in the srmmu_not_viking case,

		 * with the LEON ASI for mmuregs

		 */

		set	AC_M_CTPR, %g1

		lda	[%g1] ASI_LEON_MMUREGS, %g1	! get ctx table ptr

		sll	%g1, 0x4, %g1			! make physical addr

		lda	[%g1] ASI_M_BYPASS, %g1		! ptr to level 1 pg_table

		srl	%g1, 0x4, %g1

		sll	%g1, 0x8, %g1			! make phys addr for l1 tbl



		lda	[%g1] ASI_M_BYPASS, %g2		! get level1 entry for 0x0

		add	%g1, KERNBASE >> (SRMMU_PGDIR_SHIFT - 2), %g3

		sta	%g2, [%g3] ASI_M_BYPASS		! place at KERNBASE entry

		b	go_to_highmem

		 nop					! wheee....



/* Now do a non-relative jump so that PC is in high-memory */

go_to_highmem:

		set	execute_in_high_mem, %g1