[U-Boot] [PATCH v3] powerpc/85xx: clear out TLB on boot

Tue Aug 21 01:10:08 CEST 2012

Instead of just shooting down the entry that covers CCSR, clear out
every TLB entry that isn't the one that we're executing out of.

Signed-off-by: Scott Wood <scottwood at freescale.com>
---
v3: Don't skip the "last TLB entry" check when skipping a TLB entry
in the invalidation loop.  Sorry about the rapid updates -- this should
be the last one for this patch unless someone notices a problem.

Prabhakar, can you test that this doesn't break debugging?

 arch/powerpc/cpu/mpc85xx/start.S     |   76 +++++++++++++++++++---------------
 arch/powerpc/include/asm/mmu.h       |    4 ++
 arch/powerpc/include/asm/processor.h |    1 +
 3 files changed, 48 insertions(+), 33 deletions(-)

diff --git a/arch/powerpc/cpu/mpc85xx/start.S b/arch/powerpc/cpu/mpc85xx/start.S
index 6aabc30..5f4d19f 100644
--- a/arch/powerpc/cpu/mpc85xx/start.S
+++ b/arch/powerpc/cpu/mpc85xx/start.S
@@ -406,12 +406,11 @@ l2_disabled:
  * Search for the TLB that covers the code we're executing, and shrink it
  * so that it covers only this 4K page.  That will ensure that any other
  * TLB we create won't interfere with it.  We assume that the TLB exists,
- * which is why we don't check the Valid bit of MAS1.
+ * which is why we don't check the Valid bit of MAS1.  We also assume
+ * it is in TLB1.
  *
  * This is necessary, for example, when booting from the on-chip ROM,
  * which (oddly) creates a single 4GB TLB that covers CCSR and DDR.
- * If we don't shrink this TLB now, then we'll accidentally delete it
- * in "purge_old_ccsr_tlb" below.
  */
 	bl	nexti		/* Find our address */
 nexti:	mflr	r1		/* R1 = our PC */
@@ -421,11 +420,15 @@ nexti:	mflr	r1		/* R1 = our PC */
 	msync
 	tlbsx	0, r1		/* This must succeed */
 
+	mfspr	r14, MAS0	/* Save ESEL for later */
+	rlwinm	r14, r14, 16, 0xfff
+
 	/* Set the size of the TLB to 4KB */
 	mfspr	r3, MAS1
 	li	r2, 0xF00
 	andc	r3, r3, r2	/* Clear the TSIZE bits */
 	ori	r3, r3, MAS1_TSIZE(BOOKE_PAGESZ_4K)@l
+	oris	r3, r3, MAS1_IPROT at h
 	mtspr	MAS1, r3
 
 	/*
@@ -452,6 +455,39 @@ nexti:	mflr	r1		/* R1 = our PC */
 	tlbwe
 
 /*
+ * Clear out any other TLB entries that may exist, to avoid conflicts.
+ * Our TLB entry is in r14.
+ */
+	li	r0, TLBIVAX_ALL | TLBIVAX_TLB0
+	tlbivax 0, r0
+	tlbsync
+
+	mfspr	r4, SPRN_TLB1CFG
+	rlwinm	r4, r4, 0, TLBnCFG_NENTRY_MASK
+
+	li	r3, 0
+	mtspr	MAS1, r3
+1:	cmpw	r3, r14
+#if defined(CONFIG_SYS_PPC_E500_DEBUG_TLB) && !defined(CONFIG_NAND_SPL)
+	cmpwi	cr1, r3, CONFIG_SYS_PPC_E500_DEBUG_TLB
+	cror	cr0*4+eq, cr0*4+eq, cr1*4+eq
+#endif
+	rlwinm	r5, r3, 16, MAS0_ESEL_MSK
+	addi	r3, r3, 1
+	beq	2f		/* skip the entry we're executing from */
+
+	oris	r5, r5, MAS0_TLBSEL(1)@h
+	mtspr	MAS0, r5
+
+	isync
+	tlbwe
+	isync
+	msync
+
+2:	cmpw	r3, r4
+	blt	1b
+
+/*
  * Relocate CCSR, if necessary.  We relocate CCSR if (obviously) the default
  * location is not where we want it.  This typically happens on a 36-bit
  * system, where we want to move CCSR to near the top of 36-bit address space.
@@ -469,41 +505,15 @@ nexti:	mflr	r1		/* R1 = our PC */
 #error "CONFIG_SYS_CCSRBAR_PHYS_HIGH and CONFIG_SYS_CCSRBAR_PHYS_LOW) must be defined."
 #endif
 
-purge_old_ccsr_tlb:
-	lis	r8, CONFIG_SYS_CCSRBAR at h
-	ori	r8, r8, CONFIG_SYS_CCSRBAR at l
-	lis	r9, (CONFIG_SYS_CCSRBAR + 0x1000)@h
-	ori	r9, r9, (CONFIG_SYS_CCSRBAR + 0x1000)@l
-
-	/*
-	 * In a multi-stage boot (e.g. NAND boot), a previous stage may have
-	 * created a TLB for CCSR, which will interfere with our relocation
-	 * code.  Since we're going to create a new TLB for CCSR anyway,
-	 * it should be safe to delete this old TLB here.  We have to search
-	 * for it, though.
-	 */
-
-	li	r1, 0
-	mtspr	MAS6, r1	/* Search the current address space and PID */
-	isync
-	msync
-	tlbsx	0, r8
-	mfspr	r1, MAS1
-	andis.  r2, r1, MAS1_VALID at h	/* Check for the Valid bit */
-	beq     1f			/* Skip if no TLB found */
-
-	rlwinm	r1, r1, 0, 1, 31	/* Clear Valid bit */
-	mtspr	MAS1, r1
-	isync
-	msync
-	tlbwe
-1:
-
 create_ccsr_new_tlb:
 	/*
 	 * Create a TLB for the new location of CCSR.  Register R8 is reserved
 	 * for the virtual address of this TLB (CONFIG_SYS_CCSRBAR).
 	 */
+	lis	r8, CONFIG_SYS_CCSRBAR at h
+	ori	r8, r8, CONFIG_SYS_CCSRBAR at l
+	lis	r9, (CONFIG_SYS_CCSRBAR + 0x1000)@h
+	ori	r9, r9, (CONFIG_SYS_CCSRBAR + 0x1000)@l
 	lis     r0, FSL_BOOKE_MAS0(0, 0, 0)@h
 	ori     r0, r0, FSL_BOOKE_MAS0(0, 0, 0)@l
 	lis     r1, FSL_BOOKE_MAS1(1, 0, 0, 0, BOOKE_PAGESZ_4K)@h
diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
index 209103e..2e0e292 100644
--- a/arch/powerpc/include/asm/mmu.h
+++ b/arch/powerpc/include/asm/mmu.h
@@ -475,6 +475,10 @@ extern void print_bats(void);
 #define BOOKE_PAGESZ_256GB	14
 #define BOOKE_PAGESZ_1TB	15
 
+#define TLBIVAX_ALL		4
+#define TLBIVAX_TLB0		0
+#define TLBIVAX_TLB1		8
+
 #ifdef CONFIG_E500
 #ifndef __ASSEMBLY__
 extern void set_tlb(u8 tlb, u32 epn, u64 rpn,
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index dc009d6..0de3685 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -513,6 +513,7 @@
 
 #define SPRN_TLB0CFG	0x2B0	/* TLB 0 Config Register */
 #define SPRN_TLB1CFG	0x2B1	/* TLB 1 Config Register */
+#define   TLBnCFG_NENTRY_MASK	0x00000fff
 #define SPRN_TLB0PS	0x158	/* TLB 0 Page Size Register */
 #define SPRN_TLB1PS	0x159	/* TLB 1 Page Size Register */
 #define SPRN_MMUCSR0	0x3f4	/* MMU control and status register 0 */
-- 
1.7.9.5

