[PATCH v1 01/13] sparc32: Drop sun4m/sun4d support from head_32.S

From: Sam Ravnborg
Date: Fri Dec 18 2020 - 13:45:35 EST

Remove the most obvious parts of sun4* support from head_32.S.
Use a single print if a sun4* machine is detected thus restricting
boots to LEON machines.

Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Sam Ravnborg <sam@xxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxxxx>
Cc: Andreas Larsson <andreas@xxxxxxxxxxx>
---
arch/sparc/kernel/head_32.S | 190 ++----------------------------------
1 file changed, 9 insertions(+), 181 deletions(-)

diff --git a/arch/sparc/kernel/head_32.S b/arch/sparc/kernel/head_32.S
index be30c8d4cc73..b7b14250cbe0 100644
--- a/arch/sparc/kernel/head_32.S
+++ b/arch/sparc/kernel/head_32.S
@@ -45,11 +45,7 @@ cputypvar:
.align 4

notsup:
- .asciz "Sparc-Linux sun4/sun4c or MMU-less not supported\n\n"
- .align 4
-
-sun4e_notsup:
- .asciz "Sparc-Linux sun4e support does not exist\n\n"
+ .asciz "Sparc-Linux sun4* or MMU-less not supported\n\n"
.align 4

/* The trap-table - located in the __HEAD section */
@@ -215,114 +211,10 @@ not_a_sun4:
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_notsup
- nop
-
- /* 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.
- * We need to know if we have to play with the
- * AC bit and disable traps or not.
- */
-
- /* I've only seen MicroSparc's on SparcClassics with this
- * bit set.
- */
- set 0x800, %g2
- lda [%g0] ASI_M_MMUREGS, %g3 ! peek in the control reg
- and %g2, %g3, %g3
- subcc %g3, 0x0, %g0
- bnz srmmu_not_viking ! is in mbus mode
- nop
-
- rd %psr, %g3 ! DO NOT TOUCH %g3
- andn %g3, PSR_ET, %g2
- wr %g2, 0x0, %psr
- WRITE_PAUSE
-
- /* Get context table pointer, then convert to
- * a physical address, which is 36 bits.
- */
- set AC_M_CTPR, %g4
- lda [%g4] ASI_M_MMUREGS, %g4
- sll %g4, 0x4, %g4 ! We use this below
- ! DO NOT TOUCH %g4
-
- /* Set the AC bit in the Viking's MMU control reg. */
- lda [%g0] ASI_M_MMUREGS, %g5 ! DO NOT TOUCH %g5
- set 0x8000, %g6 ! AC bit mask
- or %g5, %g6, %g6 ! Or it in...
- sta %g6, [%g0] ASI_M_MMUREGS ! Close your eyes...
-
- /* Grrr, why does it seem like every other load/store
- * on the sun4m is in some ASI space...
- * Fine with me, let's get the pointer to the level 1
- * page table directory and fetch its entry.
- */
- lda [%g4] ASI_M_BYPASS, %o1 ! This is a level 1 ptr
- srl %o1, 0x4, %o1 ! Clear low 4 bits
- sll %o1, 0x8, %o1 ! Make physical
-
- /* Ok, pull in the PTD. */
- lda [%o1] ASI_M_BYPASS, %o2 ! This is the 0x0 16MB pgd
-
- /* Calculate to KERNBASE entry. */
- add %o1, KERNBASE >> (PGDIR_SHIFT - 2), %o3
-
- /* Poke the entry into the calculated address. */
- sta %o2, [%o3] ASI_M_BYPASS
-
- /* I don't get it Sun, if you engineered all these
- * boot loaders and the PROM (thank you for the debugging
- * features btw) why did you not have them load kernel
- * images up in high address space, since this is necessary
- * for ABI compliance anyways? Does this low-mapping provide
- * enhanced interoperability?
- *
- * "The PROM is the computer."
- */
-
- /* Ok, restore the MMU control register we saved in %g5 */
- sta %g5, [%g0] ASI_M_MMUREGS ! POW... ouch
-
- /* Turn traps back on. We saved it in %g3 earlier. */
- wr %g3, 0x0, %psr ! tick tock, tick tock
-
- /* Now we burn precious CPU cycles due to bad engineering. */
- WRITE_PAUSE
-
- /* Wow, all that just to move a 32-bit value from one
- * place to another... Jump to high memory.
- */
- b go_to_highmem
+ /* Not LEON - halt */
+ ba halt_notsup
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.
- */
- set AC_M_CTPR, %g1
- lda [%g1] ASI_M_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 >> (PGDIR_SHIFT - 2), %g3
- sta %g2, [%g3] ASI_M_BYPASS ! place at KERNBASE entry
- b go_to_highmem
- nop ! wheee....
-
-
leon_remap:
/* Sanity-check, is MMU enabled */
lda [%g0] ASI_LEON_MMUREGS, %g1
@@ -343,8 +235,6 @@ leon_remap:
lda [%g1] ASI_M_BYPASS, %g2 ! get level1 entry for 0x0
add %g1, KERNBASE >> (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:
@@ -413,13 +303,13 @@ execute_in_high_mem:
ldub [%o2 + 0x4], %l1

cmp %l1, 'm'
- be sun4m_init
+ be no_sun4_here ! sun4m
cmp %l1, 's'
- be sun4m_init
+ be no_sun4_here ! sun4m
cmp %l1, 'd'
- be sun4d_init
+ be no_sun4_here ! sun4d
cmp %l1, 'e'
- be no_sun4e_here ! Could be a sun4e.
+ be no_sun4_here ! Could be a sun4e.
nop
b no_sun4u_here ! AIEEE, a V9 sun4u... Get our BIG BROTHER kernel :))
nop
@@ -441,68 +331,6 @@ leon_init:
/* Update boot_cpu_id only on boot cpu */
stub %g1, [%g2 + %lo(boot_cpu_id)]

- ba continue_boot
- nop
-
-/* CPUID in bootbus can be found at PA 0xff0140000 */
-#define SUN4D_BOOTBUS_CPUID 0xf0140000
-
-sun4d_init:
- /* Need to patch call to handler_irq */
- set patch_handler_irq, %g4
- set sun4d_handler_irq, %g5
- sethi %hi(0x40000000), %g3 ! call
- sub %g5, %g4, %g5
- srl %g5, 2, %g5
- or %g5, %g3, %g5
- st %g5, [%g4]
-
-#ifdef CONFIG_SMP
- /* Get our CPU id out of bootbus */
- set SUN4D_BOOTBUS_CPUID, %g3
- lduba [%g3] ASI_M_CTL, %g3
- and %g3, 0xf8, %g3
- srl %g3, 3, %g4
- sta %g4, [%g0] ASI_M_VIKING_TMP1
- sethi %hi(boot_cpu_id), %g5
- stb %g4, [%g5 + %lo(boot_cpu_id)]
-#endif
-
- /* Fall through to sun4m_init */
-
-sun4m_init:
-/* Ok, the PROM could have done funny things and apple cider could still
- * be sitting in the fault status/address registers. Read them all to
- * clear them so we don't get magic faults later on.
- */
-/* This sucks, apparently this makes Vikings call prom panic, will fix later */
-2:
- rd %psr, %o1
- srl %o1, PSR_IMPL_SHIFT, %o1 ! Get a type of the CPU
-
- subcc %o1, PSR_IMPL_TI, %g0 ! TI: Viking or MicroSPARC
- be continue_boot
- nop
-
- set AC_M_SFSR, %o0
- lda [%o0] ASI_M_MMUREGS, %g0
- set AC_M_SFAR, %o0
- lda [%o0] ASI_M_MMUREGS, %g0
-
- /* Fujitsu MicroSPARC-II has no asynchronous flavors of FARs */
- subcc %o1, 0, %g0
- be continue_boot
- nop
-
- set AC_M_AFSR, %o0
- lda [%o0] ASI_M_MMUREGS, %g0
- set AC_M_AFAR, %o0
- lda [%o0] ASI_M_MMUREGS, %g0
- nop
-
-
-continue_boot:
-
/* Aieee, now set PC and nPC, enable traps, give ourselves a stack and it's
* show-time!
*/
@@ -670,9 +498,9 @@ continue_boot:
call halt_me
nop

-no_sun4e_here:
+no_sun4_here:
ld [%g7 + 0x68], %o1
- set sun4e_notsup, %o0
+ set notsup, %o0
call %o1
nop
b halt_me
--
2.27.0