powerpc/mm/radix: Add radix callbacks for early init routines

This adds routines for early setup for radix. We use device tree
property "ibm,processor-radix-AP-encodings" to find supported page
sizes. If we don't find the above we consider 64K and 4K as supported
page sizes.

We do map vmemap using 2M page size if we can. The linear mapping is
done such that we use required page size for that range. For example
memory of 3.5G is mapped such that we use 1G mapping till 3G range and
use 2M mapping for the rest.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

2 files changed, 357 insertions, 0 deletions

diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index ef778997daa9..d734934cbb1e 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_PPC_BOOK3E)	+= tlb_low_$(CONFIG_WORD_SIZE)e.o
 hash64-$(CONFIG_PPC_NATIVE)	:= hash_native_64.o
 obj-$(CONFIG_PPC_BOOK3E_64)   += pgtable-book3e.o
 obj-$(CONFIG_PPC_STD_MMU_64)	+= pgtable-hash64.o hash_utils_64.o slb_low.o slb.o $(hash64-y)
+obj-$(CONFIG_PPC_RADIX_MMU)	+= pgtable-radix.o
 obj-$(CONFIG_PPC_STD_MMU_32)	+= ppc_mmu_32.o hash_low_32.o
 obj-$(CONFIG_PPC_STD_MMU)	+= tlb_hash$(CONFIG_WORD_SIZE).o \
 				   mmu_context_hash$(CONFIG_WORD_SIZE).o
diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
new file mode 100644
index 000000000000..4918850e1061
--- /dev/null
+++ b/arch/powerpc/mm/pgtable-radix.c
@@ -0,0 +1,356 @@
+/*
+ * Page table handling routines for radix page table.
+ *
+ * Copyright 2015-2016, Aneesh Kumar K.V, IBM Corporation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#include <linux/sched.h>
+#include <linux/memblock.h>
+#include <linux/of_fdt.h>
+
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/dma.h>
+#include <asm/machdep.h>
+#include <asm/mmu.h>
+#include <asm/firmware.h>
+
+static int native_update_partition_table(u64 patb1)
+{
+	partition_tb->patb1 = cpu_to_be64(patb1);
+	return 0;
+}
+
+static __ref void *early_alloc_pgtable(unsigned long size)
+{
+	void *pt;
+
+	pt = __va(memblock_alloc_base(size, size, MEMBLOCK_ALLOC_ANYWHERE));
+	memset(pt, 0, size);
+
+	return pt;
+}
+
+int radix__map_kernel_page(unsigned long ea, unsigned long pa,
+			  pgprot_t flags,
+			  unsigned int map_page_size)
+{
+	pgd_t *pgdp;
+	pud_t *pudp;
+	pmd_t *pmdp;
+	pte_t *ptep;
+	/*
+	 * Make sure task size is correct as per the max adddr
+	 */
+	BUILD_BUG_ON(TASK_SIZE_USER64 > RADIX_PGTABLE_RANGE);
+	if (slab_is_available()) {
+		pgdp = pgd_offset_k(ea);
+		pudp = pud_alloc(&init_mm, pgdp, ea);
+		if (!pudp)
+			return -ENOMEM;
+		if (map_page_size == PUD_SIZE) {
+			ptep = (pte_t *)pudp;
+			goto set_the_pte;
+		}
+		pmdp = pmd_alloc(&init_mm, pudp, ea);
+		if (!pmdp)
+			return -ENOMEM;
+		if (map_page_size == PMD_SIZE) {
+			ptep = (pte_t *)pudp;
+			goto set_the_pte;
+		}
+		ptep = pte_alloc_kernel(pmdp, ea);
+		if (!ptep)
+			return -ENOMEM;
+	} else {
+		pgdp = pgd_offset_k(ea);
+		if (pgd_none(*pgdp)) {
+			pudp = early_alloc_pgtable(PUD_TABLE_SIZE);
+			BUG_ON(pudp == NULL);
+			pgd_populate(&init_mm, pgdp, pudp);
+		}
+		pudp = pud_offset(pgdp, ea);
+		if (map_page_size == PUD_SIZE) {
+			ptep = (pte_t *)pudp;
+			goto set_the_pte;
+		}
+		if (pud_none(*pudp)) {
+			pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
+			BUG_ON(pmdp == NULL);
+			pud_populate(&init_mm, pudp, pmdp);
+		}
+		pmdp = pmd_offset(pudp, ea);
+		if (map_page_size == PMD_SIZE) {
+			ptep = (pte_t *)pudp;
+			goto set_the_pte;
+		}
+		if (!pmd_present(*pmdp)) {
+			ptep = early_alloc_pgtable(PAGE_SIZE);
+			BUG_ON(ptep == NULL);
+			pmd_populate_kernel(&init_mm, pmdp, ptep);
+		}
+		ptep = pte_offset_kernel(pmdp, ea);
+	}
+
+set_the_pte:
+	set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, flags));
+	smp_wmb();
+	return 0;
+}
+
+static void __init radix_init_pgtable(void)
+{
+	int loop_count;
+	u64 base, end, start_addr;
+	unsigned long rts_field;
+	struct memblock_region *reg;
+	unsigned long linear_page_size;
+
+	/* We don't support slb for radix */
+	mmu_slb_size = 0;
+	/*
+	 * Create the linear mapping, using standard page size for now
+	 */
+	loop_count = 0;
+	for_each_memblock(memory, reg) {
+
+		start_addr = reg->base;
+
+redo:
+		if (loop_count < 1 && mmu_psize_defs[MMU_PAGE_1G].shift)
+			linear_page_size = PUD_SIZE;
+		else if (loop_count < 2 && mmu_psize_defs[MMU_PAGE_2M].shift)
+			linear_page_size = PMD_SIZE;
+		else
+			linear_page_size = PAGE_SIZE;
+
+		base = _ALIGN_UP(start_addr, linear_page_size);
+		end = _ALIGN_DOWN(reg->base + reg->size, linear_page_size);
+
+		pr_info("Mapping range 0x%lx - 0x%lx with 0x%lx\n",
+			(unsigned long)base, (unsigned long)end,
+			linear_page_size);
+
+		while (base < end) {
+			radix__map_kernel_page((unsigned long)__va(base),
+					      base, PAGE_KERNEL_X,
+					      linear_page_size);
+			base += linear_page_size;
+		}
+		/*
+		 * map the rest using lower page size
+		 */
+		if (end < reg->base + reg->size) {
+			start_addr = end;
+			loop_count++;
+			goto redo;
+		}
+	}
+	/*
+	 * Allocate Partition table and process table for the
+	 * host.
+	 */
+	BUILD_BUG_ON_MSG((PRTB_SIZE_SHIFT > 23), "Process table size too large.");
+	process_tb = early_alloc_pgtable(1UL << PRTB_SIZE_SHIFT);
+	/*
+	 * Fill in the process table.
+	 * we support 52 bits, hence 52-28 = 24, 11000
+	 */
+	rts_field = 3ull << PPC_BITLSHIFT(2);
+	process_tb->prtb0 = cpu_to_be64(rts_field | __pa(init_mm.pgd) | RADIX_PGD_INDEX_SIZE);
+	/*
+	 * Fill in the partition table. We are suppose to use effective address
+	 * of process table here. But our linear mapping also enable us to use
+	 * physical address here.
+	 */
+	ppc_md.update_partition_table(__pa(process_tb) | (PRTB_SIZE_SHIFT - 12) | PATB_GR);
+	pr_info("Process table %p and radix root for kernel: %p\n", process_tb, init_mm.pgd);
+}
+
+static void __init radix_init_partition_table(void)
+{
+	unsigned long rts_field;
+	/*
+	 * we support 52 bits, hence 52-28 = 24, 11000
+	 */
+	rts_field = 3ull << PPC_BITLSHIFT(2);
+
+	BUILD_BUG_ON_MSG((PATB_SIZE_SHIFT > 24), "Partition table size too large.");
+	partition_tb = early_alloc_pgtable(1UL << PATB_SIZE_SHIFT);
+	partition_tb->patb0 = cpu_to_be64(rts_field | __pa(init_mm.pgd) |
+					  RADIX_PGD_INDEX_SIZE | PATB_HR);
+	printk("Partition table %p\n", partition_tb);
+
+	memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE);
+	/*
+	 * update partition table control register,
+	 * 64 K size.
+	 */
+	mtspr(SPRN_PTCR, __pa(partition_tb) | (PATB_SIZE_SHIFT - 12));
+}
+
+void __init radix_init_native(void)
+{
+	ppc_md.update_partition_table = native_update_partition_table;
+}
+
+static int __init get_idx_from_shift(unsigned int shift)
+{
+	int idx = -1;
+
+	switch (shift) {
+	case 0xc:
+		idx = MMU_PAGE_4K;
+		break;
+	case 0x10:
+		idx = MMU_PAGE_64K;
+		break;
+	case 0x15:
+		idx = MMU_PAGE_2M;
+		break;
+	case 0x1e:
+		idx = MMU_PAGE_1G;
+		break;
+	}
+	return idx;
+}
+
+static int __init radix_dt_scan_page_sizes(unsigned long node,
+					   const char *uname, int depth,
+					   void *data)
+{
+	int size = 0;
+	int shift, idx;
+	unsigned int ap;
+	const __be32 *prop;
+	const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
+
+	/* We are scanning "cpu" nodes only */
+	if (type == NULL || strcmp(type, "cpu") != 0)
+		return 0;
+
+	prop = of_get_flat_dt_prop(node, "ibm,processor-radix-AP-encodings", &size);
+	if (!prop)
+		return 0;
+
+	pr_info("Page sizes from device-tree:\n");
+	for (; size >= 4; size -= 4, ++prop) {
+
+		struct mmu_psize_def *def;
+
+		/* top 3 bit is AP encoding */
+		shift = be32_to_cpu(prop[0]) & ~(0xe << 28);
+		ap = be32_to_cpu(prop[0]) >> 29;
+		pr_info("Page size sift = %d AP=0x%x\n", shift, ap);
+
+		idx = get_idx_from_shift(shift);
+		if (idx < 0)
+			continue;
+
+		def = &mmu_psize_defs[idx];
+		def->shift = shift;
+		def->ap  = ap;
+	}
+
+	/* needed ? */
+	cur_cpu_spec->mmu_features &= ~MMU_FTR_NO_SLBIE_B;
+	return 1;
+}
+
+static void __init radix_init_page_sizes(void)
+{
+	int rc;
+
+	/*
+	 * Try to find the available page sizes in the device-tree
+	 */
+	rc = of_scan_flat_dt(radix_dt_scan_page_sizes, NULL);
+	if (rc != 0)  /* Found */
+		goto found;
+	/*
+	 * let's assume we have page 4k and 64k support
+	 */
+	mmu_psize_defs[MMU_PAGE_4K].shift = 12;
+	mmu_psize_defs[MMU_PAGE_4K].ap = 0x0;
+
+	mmu_psize_defs[MMU_PAGE_64K].shift = 16;
+	mmu_psize_defs[MMU_PAGE_64K].ap = 0x5;
+found:
+#ifdef CONFIG_SPARSEMEM_VMEMMAP
+	if (mmu_psize_defs[MMU_PAGE_2M].shift) {
+		/*
+		 * map vmemmap using 2M if available
+		 */
+		mmu_vmemmap_psize = MMU_PAGE_2M;
+	}
+#endif /* CONFIG_SPARSEMEM_VMEMMAP */
+	return;
+}
+
+void __init radix__early_init_mmu(void)
+{
+	unsigned long lpcr;
+	/*
+	 * setup LPCR UPRT based on mmu_features
+	 */
+	lpcr = mfspr(SPRN_LPCR);
+	mtspr(SPRN_LPCR, lpcr | LPCR_UPRT);
+
+#ifdef CONFIG_PPC_64K_PAGES
+	/* PAGE_SIZE mappings */
+	mmu_virtual_psize = MMU_PAGE_64K;
+#else
+	mmu_virtual_psize = MMU_PAGE_4K;
+#endif
+
+#ifdef CONFIG_SPARSEMEM_VMEMMAP
+	/* vmemmap mapping */
+	mmu_vmemmap_psize = mmu_virtual_psize;
+#endif
+	/*
+	 * initialize page table size
+	 */
+	__pte_index_size = RADIX_PTE_INDEX_SIZE;
+	__pmd_index_size = RADIX_PMD_INDEX_SIZE;
+	__pud_index_size = RADIX_PUD_INDEX_SIZE;
+	__pgd_index_size = RADIX_PGD_INDEX_SIZE;
+	__pmd_cache_index = RADIX_PMD_INDEX_SIZE;
+	__pte_table_size = RADIX_PTE_TABLE_SIZE;
+	__pmd_table_size = RADIX_PMD_TABLE_SIZE;
+	__pud_table_size = RADIX_PUD_TABLE_SIZE;
+	__pgd_table_size = RADIX_PGD_TABLE_SIZE;
+
+	radix_init_page_sizes();
+
+	if (!firmware_has_feature(FW_FEATURE_LPAR))
+		radix_init_partition_table();
+
+	radix_init_pgtable();
+}
+
+void radix__early_init_mmu_secondary(void)
+{
+	unsigned long lpcr;
+	/*
+	 * setup LPCR UPRT based on mmu_features
+	 */
+	lpcr = mfspr(SPRN_LPCR);
+	mtspr(SPRN_LPCR, lpcr | LPCR_UPRT);
+	/*
+	 * update partition table control register, 64 K size.
+	 */
+	if (!firmware_has_feature(FW_FEATURE_LPAR))
+		mtspr(SPRN_PTCR,
+		      __pa(partition_tb) | (PATB_SIZE_SHIFT - 12));
+}
+
+void radix__setup_initial_memory_limit(phys_addr_t first_memblock_base,
+				phys_addr_t first_memblock_size)
+{
+	/* Finally limit subsequent allocations */
+	memblock_set_current_limit(first_memblock_base + first_memblock_size);
+}