powerpc/85xx: relocate CCSR before creating the initial RAM area

Before main memory (DDR) is initialized, the on-chip L1 cache is used as a
memory area for the stack and the global data (gd_t) structure.  This is
called the initial RAM area, or initram.  The L1 cache is locked and the TLBs
point to a non-existent address (so that there's no chance it will overlap
main memory or any device).  The L1 cache is also configured not to write
out to memory or the L2 cache, so everything stays in the L1 cache.

One of the things we might do while running out of initram is relocate CCSR.
On reset, CCSR is typically located at some high 32-bit address, like
0xfe000000, and this may not be the best place for CCSR.  For example, on
36-bit systems, CCSR is relocated to 0xffe000000, near the top of 36-bit
memory space.

On some future Freescale SOCs, the L1 cache will be forced to write to the
backing store, so we can no longer have the TLBs point to non-existent address.
Instead, we will point the TLBs to an unused area in CCSR.  In order for this
technique to work, CCSR needs to be relocated before the initram memory is
enabled.

Unlike the original CCSR relocation code in cpu_init_early_f(), the TLBs
we create now for relocating CCSR are deleted after the relocation is finished.
cpu_init_early_f() will still need to create a TLB for CCSR (at the new
location) for normal U-Boot purposes.  This is done to keep the impact to
existing U-Boot code minimal and to better isolate the CCSR relocation code.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

2 files changed, 234 insertions, 58 deletions

diff --git a/arch/powerpc/cpu/mpc85xx/cpu_init_early.c b/arch/powerpc/cpu/mpc85xx/cpu_init_early.c
index 32aa94b..64eda94 100644
--- a/arch/powerpc/cpu/mpc85xx/cpu_init_early.c
+++ b/arch/powerpc/cpu/mpc85xx/cpu_init_early.c
@@ -24,51 +24,6 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-#if (CONFIG_SYS_CCSRBAR_DEFAULT != CONFIG_SYS_CCSRBAR_PHYS)
-#ifdef CONFIG_FSL_CORENET
-static void setup_ccsrbar(void)
-{
-	u32 temp;
-	volatile u32 *ccsr_virt = (volatile u32 *)(CONFIG_SYS_CCSRBAR + 0x1000);
-	volatile ccsr_local_t *ccm;
-
-	/*
-	 * We can't call set_law() because we haven't moved
-	 * CCSR yet.
-	 */
-	ccm = (void *)ccsr_virt;
-
-	out_be32(&ccm->law[0].lawbarh,
-		(u64)CONFIG_SYS_CCSRBAR_PHYS >> 32);
-	out_be32(&ccm->law[0].lawbarl, (u32)CONFIG_SYS_CCSRBAR_PHYS);
-	out_be32(&ccm->law[0].lawar,
-		LAW_EN | (0x1e << 20) | LAW_SIZE_4K);
-
-	in_be32((u32 *)(ccsr_virt + 0));
-	in_be32((u32 *)(ccsr_virt + 1));
-	isync();
-
-	ccm = (void *)CONFIG_SYS_CCSRBAR;
-	/* Now use the temporary LAW to move CCSR */
-	out_be32(&ccm->ccsrbarh, (u64)CONFIG_SYS_CCSRBAR_PHYS >> 32);
-	out_be32(&ccm->ccsrbarl, (u32)CONFIG_SYS_CCSRBAR_PHYS);
-	out_be32(&ccm->ccsrar, CCSRAR_C);
-	temp = in_be32(&ccm->ccsrar);
-	disable_law(0);
-}
-#else
-static void setup_ccsrbar(void)
-{
-	u32 temp;
-	volatile u32 *ccsr_virt = (volatile u32 *)(CONFIG_SYS_CCSRBAR + 0x1000);
-
-	temp = in_be32(ccsr_virt);
-	out_be32(ccsr_virt, CONFIG_SYS_CCSRBAR_PHYS >> 12);
-	temp = in_be32((volatile u32 *)CONFIG_SYS_CCSRBAR);
-}
-#endif
-#endif
-
 /* We run cpu_init_early_f in AS = 1 */
 void cpu_init_early_f(void)
 {
@@ -93,19 +48,6 @@ void cpu_init_early_f(void)
 
 	write_tlb(mas0, mas1, mas2, mas3, mas7);
 
-	/* set up CCSR if we want it moved */
-#if (CONFIG_SYS_CCSRBAR_DEFAULT != CONFIG_SYS_CCSRBAR_PHYS)
-	mas0 = MAS0_TLBSEL(0) | MAS0_ESEL(1);
-	/* mas1 is the same as above */
-	mas2 = FSL_BOOKE_MAS2(CONFIG_SYS_CCSRBAR + 0x1000, MAS2_I|MAS2_G);
-	mas3 = FSL_BOOKE_MAS3(CONFIG_SYS_CCSRBAR_DEFAULT, 0, MAS3_SW|MAS3_SR);
-	mas7 = FSL_BOOKE_MAS7(CONFIG_SYS_CCSRBAR_DEFAULT);
-
-	write_tlb(mas0, mas1, mas2, mas3, mas7);
-
-	setup_ccsrbar();
-#endif
-
 	init_laws();
 	invalidate_tlb(0);
 	init_tlbs();
diff --git a/arch/powerpc/cpu/mpc85xx/start.S b/arch/powerpc/cpu/mpc85xx/start.S
index 878a3d6..d89d18c 100644
--- a/arch/powerpc/cpu/mpc85xx/start.S
+++ b/arch/powerpc/cpu/mpc85xx/start.S
@@ -279,6 +279,240 @@ _start_e500:
 
 #endif /* CONFIG_MPC8569 */
 
+/*
+ * 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.
+ *
+ * To move CCSR, we create two temporary TLBs, one for the old location, and
+ * another for the new location.  On CoreNet systems, we also need to create
+ * a special, temporary LAW.
+ *
+ * As a general rule, TLB0 is used for short-term TLBs, and TLB1 is used for
+ * long-term TLBs, so we use TLB0 here.
+ */
+#if (CONFIG_SYS_CCSRBAR_DEFAULT != CONFIG_SYS_CCSRBAR_PHYS)
+
+#if !defined(CONFIG_SYS_CCSRBAR_PHYS_HIGH) || !defined(CONFIG_SYS_CCSRBAR_PHYS_LOW)
+#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@h
+	ori	r8, r8, CONFIG_SYS_CCSRBAR@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 */
+	tlbsx	0, r8
+	mfspr	r1, MAS1
+	andis.  r2, r1, MAS1_VALID@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
+	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     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
+	ori     r1, r1, FSL_BOOKE_MAS1(1, 0, 0, 0, BOOKE_PAGESZ_4K)@l
+	lis     r2, FSL_BOOKE_MAS2(CONFIG_SYS_CCSRBAR, (MAS2_I|MAS2_G))@h
+	ori     r2, r2, FSL_BOOKE_MAS2(CONFIG_SYS_CCSRBAR, (MAS2_I|MAS2_G))@l
+	lis     r3, FSL_BOOKE_MAS3(CONFIG_SYS_CCSRBAR_PHYS_LOW, 0, (MAS3_SW|MAS3_SR))@h
+	ori     r3, r3, FSL_BOOKE_MAS3(CONFIG_SYS_CCSRBAR_PHYS_LOW, 0, (MAS3_SW|MAS3_SR))@l
+	lis	r7, CONFIG_SYS_CCSRBAR_PHYS_HIGH@h
+	ori	r7, r7, CONFIG_SYS_CCSRBAR_PHYS_HIGH@l
+	mtspr   MAS0, r0
+	mtspr   MAS1, r1
+	mtspr   MAS2, r2
+	mtspr   MAS3, r3
+	mtspr   MAS7, r7
+	isync
+	msync
+	tlbwe
+
+	/*
+	 * Create a TLB for the old location of CCSR.  Register R9 is reserved
+	 * for the virtual address of this TLB (CONFIG_SYS_CCSRBAR + 0x1000).
+	 */
+create_ccsr_old_tlb:
+	lis     r0, FSL_BOOKE_MAS0(0, 1, 0)@h
+	ori     r0, r0, FSL_BOOKE_MAS0(0, 1, 0)@l
+	lis     r2, FSL_BOOKE_MAS2(CONFIG_SYS_CCSRBAR + 0x1000, (MAS2_I|MAS2_G))@h
+	ori     r2, r2, FSL_BOOKE_MAS2(CONFIG_SYS_CCSRBAR + 0x1000, (MAS2_I|MAS2_G))@l
+	lis     r3, FSL_BOOKE_MAS3(CONFIG_SYS_CCSRBAR_DEFAULT, 0, (MAS3_SW|MAS3_SR))@h
+	ori     r3, r3, FSL_BOOKE_MAS3(CONFIG_SYS_CCSRBAR_DEFAULT, 0, (MAS3_SW|MAS3_SR))@l
+	li	r7, 0	/* The default CCSR address is always a 32-bit number */
+	mtspr   MAS0, r0
+	/* MAS1 is the same as above */
+	mtspr   MAS2, r2
+	mtspr   MAS3, r3
+	mtspr   MAS7, r7
+	isync
+	msync
+	tlbwe
+
+#ifdef CONFIG_FSL_CORENET
+
+#define CCSR_LAWBARH0	(CONFIG_SYS_CCSRBAR + 0x1000)
+#define LAW_EN		0x80000000
+#define LAW_SIZE_4K	0xb
+#define CCSRBAR_LAWAR	(LAW_EN | (0x1e << 20) | LAW_SIZE_4K)
+#define CCSRAR_C	0x80000000	/* Commit */
+
+create_temp_law:
+	/*
+	 * On CoreNet systems, we create the temporary LAW using a special LAW
+	 * target ID of 0x1e.  LAWBARH is at offset 0xc00 in CCSR.
+	 */
+	lis     r0, CONFIG_SYS_CCSRBAR_PHYS_HIGH@h
+	ori     r0, r0, CONFIG_SYS_CCSRBAR_PHYS_HIGH@l
+	lis     r1, CONFIG_SYS_CCSRBAR_PHYS_LOW@h
+	ori     r1, r1, CONFIG_SYS_CCSRBAR_PHYS_LOW@l
+	lis     r2, CCSRBAR_LAWAR@h
+	ori     r2, r2, CCSRBAR_LAWAR@l
+
+	stw     r0, 0xc00(r9)	/* LAWBARH0 */
+	stw     r1, 0xc04(r9)	/* LAWBARL0 */
+	sync
+	stw     r2, 0xc08(r9)	/* LAWAR0 */
+
+	/*
+	 * Read back from LAWAR to ensure the update is complete.  e500mc
+	 * cores also require an isync.
+	 */
+	lwz	r0, 0xc08(r9)	/* LAWAR0 */
+	isync
+
+	/*
+	 * Read the current CCSRBARH and CCSRBARL using load word instructions.
+	 * Follow this with an isync instruction. This forces any outstanding
+	 * accesses to configuration space to completion.
+	 */
+read_old_ccsrbar:
+	lwz	r0, 0(r9)	/* CCSRBARH */
+	lwz	r0, 4(r9)	/* CCSRBARH */
+	isync
+
+	/*
+	 * Write the new values for CCSRBARH and CCSRBARL to their old
+	 * locations.  The CCSRBARH has a shadow register. When the CCSRBARH
+	 * has a new value written it loads a CCSRBARH shadow register. When
+	 * the CCSRBARL is written, the CCSRBARH shadow register contents
+	 * along with the CCSRBARL value are loaded into the CCSRBARH and
+	 * CCSRBARL registers, respectively.  Follow this with a sync
+	 * instruction.
+	 */
+write_new_ccsrbar:
+	lis	r0, CONFIG_SYS_CCSRBAR_PHYS_HIGH@h
+	ori	r0, r0, CONFIG_SYS_CCSRBAR_PHYS_HIGH@l
+	lis	r1, CONFIG_SYS_CCSRBAR_PHYS_LOW@h
+	ori	r1, r1, CONFIG_SYS_CCSRBAR_PHYS_LOW@l
+	lis	r2, CCSRAR_C@h
+	ori	r2, r2, CCSRAR_C@l
+
+	stw	r0, 0(r9)	/* Write to CCSRBARH */
+	sync			/* Make sure we write to CCSRBARH first */
+	stw	r1, 4(r9)	/* Write to CCSRBARL */
+	sync
+
+	/*
+	 * Write a 1 to the commit bit (C) of CCSRAR at the old location.
+	 * Follow this with a sync instruction.
+	 */
+	stw	r2, 8(r9)
+	sync
+
+	/* Delete the temporary LAW */
+delete_temp_law:
+	li	r1, 0
+	stw	r1, 0xc08(r8)
+	sync
+	stw	r1, 0xc00(r8)
+	stw	r1, 0xc04(r8)
+	sync
+
+#else /* #ifdef CONFIG_FSL_CORENET */
+
+write_new_ccsrbar:
+	/*
+	 * Read the current value of CCSRBAR using a load word instruction
+	 * followed by an isync. This forces all accesses to configuration
+	 * space to complete.
+	 */
+	sync
+	lwz	r0, 0(r9)
+	isync
+
+/* CONFIG_SYS_CCSRBAR_PHYS right shifted by 12 */
+#define CCSRBAR_PHYS_RS12 ((CONFIG_SYS_CCSRBAR_PHYS_HIGH << 20) | \
+			   (CONFIG_SYS_CCSRBAR_PHYS_LOW >> 12))
+
+	/* Write the new value to CCSRBAR. */
+	lis	r0, CCSRBAR_PHYS_RS12@h
+	ori	r0, r0, CCSRBAR_PHYS_RS12@l
+	stw	r0, 0(r9)
+	sync
+
+	/*
+	 * The manual says to perform a load of an address that does not
+	 * access configuration space or the on-chip SRAM using an existing TLB,
+	 * but that doesn't appear to be necessary.  We will do the isync,
+	 * though.
+	 */
+	isync
+
+	/*
+	 * Read the contents of CCSRBAR from its new location, followed by
+	 * another isync.
+	 */
+	lwz	r0, 0(r8)
+	isync
+
+#endif  /* #ifdef CONFIG_FSL_CORENET */
+
+	/* Delete the temporary TLBs */
+delete_temp_tlbs:
+	lis     r0, FSL_BOOKE_MAS0(0, 0, 0)@h
+	ori     r0, r0, FSL_BOOKE_MAS0(0, 0, 0)@l
+	li	r1, 0
+	lis     r2, FSL_BOOKE_MAS2(CONFIG_SYS_CCSRBAR, (MAS2_I|MAS2_G))@h
+	ori     r2, r2, FSL_BOOKE_MAS2(CONFIG_SYS_CCSRBAR, (MAS2_I|MAS2_G))@l
+	mtspr   MAS0, r0
+	mtspr   MAS1, r1
+	mtspr   MAS2, r2
+	isync
+	msync
+	tlbwe
+
+	lis     r0, FSL_BOOKE_MAS0(0, 1, 0)@h
+	ori     r0, r0, FSL_BOOKE_MAS0(0, 1, 0)@l
+	lis     r2, FSL_BOOKE_MAS2(CONFIG_SYS_CCSRBAR + 0x1000, (MAS2_I|MAS2_G))@h
+	ori     r2, r2, FSL_BOOKE_MAS2(CONFIG_SYS_CCSRBAR + 0x1000, (MAS2_I|MAS2_G))@l
+	mtspr   MAS0, r0
+	mtspr   MAS2, r2
+	isync
+	msync
+	tlbwe
+#endif /* #if (CONFIG_SYS_CCSRBAR_DEFAULT != CONFIG_SYS_CCSRBAR_PHYS) */
+
+create_init_ram_area:
 	lis     r6,FSL_BOOKE_MAS0(1, 15, 0)@h
 	ori     r6,r6,FSL_BOOKE_MAS0(1, 15, 0)@l