[U-Boot] [PATCH] ppc/85xx: Add tracking of TLB CAM usage

[Kumar Gala]

We need to track which TLB CAM entries are used to allow us to
"dynamically" allocate entries later in the code.  For example the SPD
DDR code today hard codes which TLB entries it uses.  We can now make
that pick entries that are free.

Signed-off-by: Kumar Gala <galak at kernel.crashing.org>
---
* Fix whitespace
* Fix find_free_tlbcam when used_tlb_cams array has more than
  one element.

 cpu/mpc85xx/cpu_init.c        |    1 +
 cpu/mpc85xx/tlb.c             |   64 +++++++++++++++++++++++++++++++++++++++++
 include/asm-ppc/config.h      |    7 ++++
 include/asm-ppc/global_data.h |    3 ++
 include/asm-ppc/mmu.h         |    2 +
 5 files changed, 77 insertions(+), 0 deletions(-)

diff --git a/cpu/mpc85xx/cpu_init.c b/cpu/mpc85xx/cpu_init.c
index 16ce82c..e0126d3 100644
--- a/cpu/mpc85xx/cpu_init.c
+++ b/cpu/mpc85xx/cpu_init.c
@@ -246,6 +246,7 @@ void cpu_init_f (void)
 #ifdef CONFIG_FSL_CORENET
 	corenet_tb_init();
 #endif
+	init_used_tlb_cams();
 }
 
 
diff --git a/cpu/mpc85xx/tlb.c b/cpu/mpc85xx/tlb.c
index ea5deb2..234fdaa 100644
--- a/cpu/mpc85xx/tlb.c
+++ b/cpu/mpc85xx/tlb.c
@@ -56,12 +56,74 @@ void init_tlbs(void)
 }
 
 #ifndef CONFIG_NAND_SPL
+static inline void use_tlb_cam(u8 idx)
+{
+	int i = idx / 32;
+	int bit = idx % 32;
+
+	gd->used_tlb_cams[i] |= (1 << bit);
+}
+
+static inline void free_tlb_cam(u8 idx)
+{
+	int i = idx / 32;
+	int bit = idx % 32;
+
+	gd->used_tlb_cams[i] &= ~(1 << bit);
+}
+
+void init_used_tlb_cams(void)
+{
+	int i;
+	unsigned int num_cam = mfspr(SPRN_TLB1CFG) & 0xfff;
+
+	for (i = 0; i < ((CONFIG_SYS_NUM_TLBCAMS+31)/32); i++)
+		gd->used_tlb_cams[i] = 0;
+
+	/* walk all the entries */
+	for (i = 0; i < num_cam; i++) {
+		u32 _mas1;
+
+		mtspr(MAS0, FSL_BOOKE_MAS0(1, i, 0));
+
+		asm volatile("tlbre;isync");
+		_mas1 = mfspr(MAS1);
+
+		/* if the entry isn't valid skip it */
+		if ((_mas1 & MAS1_VALID))
+			use_tlb_cam(i);
+	}
+}
+
+int find_free_tlbcam(void)
+{
+	int i;
+	u32 idx;
+
+	for (i = 0; i < ((CONFIG_SYS_NUM_TLBCAMS+31)/32); i++) {
+		idx = ffz(gd->used_tlb_cams[i]);
+
+		if (idx != 32)
+			break;
+	}
+
+	idx += i * 32;
+
+	if (idx >= CONFIG_SYS_NUM_TLBCAMS)
+		return -1;
+
+	return idx;
+}
+
 void set_tlb(u8 tlb, u32 epn, u64 rpn,
 	     u8 perms, u8 wimge,
 	     u8 ts, u8 esel, u8 tsize, u8 iprot)
 {
 	u32 _mas0, _mas1, _mas2, _mas3, _mas7;
 
+	if (tlb == 1)
+		use_tlb_cam(esel);
+
 	_mas0 = FSL_BOOKE_MAS0(tlb, esel, 0);
 	_mas1 = FSL_BOOKE_MAS1(1, iprot, 0, ts, tsize);
 	_mas2 = FSL_BOOKE_MAS2(epn, wimge);
@@ -80,6 +142,8 @@ void disable_tlb(u8 esel)
 {
 	u32 _mas0, _mas1, _mas2, _mas3, _mas7;
 
+	free_tlb_cam(esel);
+
 	_mas0 = FSL_BOOKE_MAS0(1, esel, 0);
 	_mas1 = 0;
 	_mas2 = 0;
diff --git a/include/asm-ppc/config.h b/include/asm-ppc/config.h
index d5f82b4..796707e 100644
--- a/include/asm-ppc/config.h
+++ b/include/asm-ppc/config.h
@@ -63,6 +63,13 @@
 #define CONFIG_TSECV2
 #endif
 
+/* Number of TLB CAM entries we have on FSL Book-E chips */
+#if defined(CONFIG_E500MC)
+#define CONFIG_SYS_NUM_TLBCAMS	64
+#elif defined(CONFIG_E500)
+#define CONFIG_SYS_NUM_TLBCAMS	16
+#endif
+
 /* Relocation to SDRAM works on all PPC boards */
 #define CONFIG_RELOC_FIXUP_WORKS
 
diff --git a/include/asm-ppc/global_data.h b/include/asm-ppc/global_data.h
index 55e7e20..3f11918 100644
--- a/include/asm-ppc/global_data.h
+++ b/include/asm-ppc/global_data.h
@@ -107,6 +107,9 @@ typedef	struct	global_data {
 #if defined(CONFIG_FSL_LAW)
 	u32 used_laws;
 #endif
+#if defined(CONFIG_E500)
+	u32 used_tlb_cams[(CONFIG_SYS_NUM_TLBCAMS+31)/32];
+#endif
 #if defined(CONFIG_MPC5xxx)
 	unsigned long	ipb_clk;
 	unsigned long	pci_clk;
diff --git a/include/asm-ppc/mmu.h b/include/asm-ppc/mmu.h
index ec22a50..fd10249 100644
--- a/include/asm-ppc/mmu.h
+++ b/include/asm-ppc/mmu.h
@@ -479,6 +479,8 @@ extern void disable_tlb(u8 esel);
 extern void invalidate_tlb(u8 tlb);
 extern void init_tlbs(void);
 extern int find_tlb_idx(void *addr, u8 tlbsel);
+extern void init_used_tlb_cams(void);
+extern int find_free_tlbcam(void);
 
 extern unsigned int setup_ddr_tlbs(unsigned int memsize_in_meg);
 
-- 
1.6.0.6