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Subject[PATCH v1 32/46] powerpc/8xx: Don't set IMMR map anymore at boot
Date
Only early debug requires IMMR to be mapped early.

No need to set it up and pin it in assembly. Map it
through page tables at udbg init when necessary.

If CONFIG_PIN_TLB_IMMR is selected, pin it once we
don't need the 32 Mb pinned RAM anymore.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/kernel/head_8xx.S | 36 ++++++++++++------------------
arch/powerpc/mm/mmu_decl.h | 4 ++++
arch/powerpc/mm/nohash/8xx.c | 15 +++++++++----
arch/powerpc/platforms/8xx/Kconfig | 2 +-
arch/powerpc/sysdev/cpm_common.c | 2 ++
5 files changed, 32 insertions(+), 27 deletions(-)

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 84b3c7692b37..6a1a74e9b011 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -748,6 +748,20 @@ start_here:
rfi
/* Load up the kernel context */
2:
+#ifdef CONFIG_PIN_TLB_IMMR
+ mfspr r0, SPRN_MD_CTR
+ ori r0, r0, 0x1f00
+ mtspr SPRN_MD_CTR, r0
+ LOAD_REG_IMMEDIATE(r0, VIRT_IMMR_BASE | MD_EVALID)
+ mtspr SPRN_MD_EPN, r0
+ LOAD_REG_IMMEDIATE(r0, MD_SVALID | MD_PS512K | MD_GUARDED)
+ mtspr SPRN_MD_TWC, r0
+ mfspr r0, SPRN_IMMR
+ rlwinm r0, r0, 0, 0xfff80000
+ ori r0, r0, 0xf0 | _PAGE_DIRTY | _PAGE_SPS | _PAGE_SH | \
+ _PAGE_NO_CACHE | _PAGE_PRESENT
+ mtspr SPRN_MD_RPN, r0
+#endif
tlbia /* Clear all TLB entries */
sync /* wait for tlbia/tlbie to finish */

@@ -796,28 +810,6 @@ initial_mmu:
ori r8, r8, MD_APG_INIT@l
mtspr SPRN_MD_AP, r8

- /* Map a 512k page for the IMMR to get the processor
- * internal registers (among other things).
- */
-#ifdef CONFIG_PIN_TLB_IMMR
- oris r10, r10, MD_RSV4I@h
- ori r10, r10, 0x1c00
- mtspr SPRN_MD_CTR, r10
-
- mfspr r9, 638 /* Get current IMMR */
- andis. r9, r9, 0xfff8 /* Get 512 kbytes boundary */
-
- lis r8, VIRT_IMMR_BASE@h /* Create vaddr for TLB */
- ori r8, r8, MD_EVALID /* Mark it valid */
- mtspr SPRN_MD_EPN, r8
- li r8, MD_PS512K | MD_GUARDED /* Set 512k byte page */
- ori r8, r8, MD_SVALID /* Make it valid */
- mtspr SPRN_MD_TWC, r8
- mr r8, r9 /* Create paddr for TLB */
- ori r8, r8, MI_BOOTINIT|0x2 /* Inhibit cache -- Cort */
- mtspr SPRN_MD_RPN, r8
-#endif
-
/* Now map the lower RAM (up to 32 Mbytes) into the ITLB. */
#ifdef CONFIG_PIN_TLB_TEXT
lis r8, MI_RSV4I@h
diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
index 7097e07a209a..1b6d39e9baed 100644
--- a/arch/powerpc/mm/mmu_decl.h
+++ b/arch/powerpc/mm/mmu_decl.h
@@ -182,6 +182,10 @@ static inline void mmu_mark_initmem_nx(void) { }
static inline void mmu_mark_rodata_ro(void) { }
#endif

+#ifdef CONFIG_PPC_8xx
+void __init mmu_mapin_immr(void);
+#endif
+
#ifdef CONFIG_PPC_DEBUG_WX
void ptdump_check_wx(void);
#else
diff --git a/arch/powerpc/mm/nohash/8xx.c b/arch/powerpc/mm/nohash/8xx.c
index 3189308dece4..2a55904986c6 100644
--- a/arch/powerpc/mm/nohash/8xx.c
+++ b/arch/powerpc/mm/nohash/8xx.c
@@ -65,7 +65,7 @@ void __init MMU_init_hw(void)
if (IS_ENABLED(CONFIG_PIN_TLB_DATA)) {
unsigned long ctr = mfspr(SPRN_MD_CTR) & 0xfe000000;
unsigned long flags = 0xf0 | MD_SPS16K | _PAGE_SH | _PAGE_DIRTY;
- int i = IS_ENABLED(CONFIG_PIN_TLB_IMMR) ? 29 : 28;
+ int i = 28;
unsigned long addr = 0;
unsigned long mem = total_lowmem;

@@ -80,12 +80,19 @@ void __init MMU_init_hw(void)
}
}

-static void __init mmu_mapin_immr(void)
+static bool immr_is_mapped __initdata;
+
+void __init mmu_mapin_immr(void)
{
unsigned long p = PHYS_IMMR_BASE;
unsigned long v = VIRT_IMMR_BASE;
int offset;

+ if (immr_is_mapped)
+ return;
+
+ immr_is_mapped = true;
+
for (offset = 0; offset < IMMR_SIZE; offset += PAGE_SIZE)
map_kernel_page(v + offset, p + offset, PAGE_KERNEL_NCG);
}
@@ -121,9 +128,10 @@ unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
{
unsigned long mapped;

+ mmu_mapin_immr();
+
if (__map_without_ltlbs) {
mapped = 0;
- mmu_mapin_immr();
if (!IS_ENABLED(CONFIG_PIN_TLB_IMMR))
patch_instruction_site(&patch__dtlbmiss_immr_jmp, PPC_INST_NOP);
if (!IS_ENABLED(CONFIG_PIN_TLB_TEXT))
@@ -142,7 +150,6 @@ unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
*/
mmu_mapin_ram_chunk(0, einittext8, PAGE_KERNEL_X);
mmu_mapin_ram_chunk(einittext8, mapped, PAGE_KERNEL);
- mmu_mapin_immr();
}

mmu_patch_cmp_limit(&patch__dtlbmiss_linmem_top, mapped);
diff --git a/arch/powerpc/platforms/8xx/Kconfig b/arch/powerpc/platforms/8xx/Kconfig
index 0d036cd868ef..04ea1a8a0bdc 100644
--- a/arch/powerpc/platforms/8xx/Kconfig
+++ b/arch/powerpc/platforms/8xx/Kconfig
@@ -187,7 +187,7 @@ config PIN_TLB_DATA

config PIN_TLB_IMMR
bool "Pinned TLB for IMMR"
- depends on PIN_TLB || PPC_EARLY_DEBUG_CPM
+ depends on PIN_TLB
default y
help
This pins the IMMR area with a 512kbytes page. In case
diff --git a/arch/powerpc/sysdev/cpm_common.c b/arch/powerpc/sysdev/cpm_common.c
index 71660bacb264..7dc1960f8bdb 100644
--- a/arch/powerpc/sysdev/cpm_common.c
+++ b/arch/powerpc/sysdev/cpm_common.c
@@ -68,6 +68,8 @@ static void udbg_putc_cpm(char c)
void __init udbg_init_cpm(void)
{
#ifdef CONFIG_PPC_8xx
+ mmu_mapin_immr();
+
cpm_udbg_txdesc = (u32 __iomem __force *)
(CONFIG_PPC_EARLY_DEBUG_CPM_ADDR - PHYS_IMMR_BASE +
VIRT_IMMR_BASE);
--
2.25.0
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