From 76cb841cb886eef6b3bee341a2266c76578724ad Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Mon, 6 May 2024 03:02:30 +0200
Subject: Adding upstream version 4.19.249.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 arch/xtensa/mm/mmu.c | 114 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 arch/xtensa/mm/mmu.c

(limited to 'arch/xtensa/mm/mmu.c')

diff --git a/arch/xtensa/mm/mmu.c b/arch/xtensa/mm/mmu.c
new file mode 100644
index 000000000..470843188
--- /dev/null
+++ b/arch/xtensa/mm/mmu.c
@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * xtensa mmu stuff
+ *
+ * Extracted from init.c
+ */
+#include <linux/bootmem.h>
+#include <linux/percpu.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/cache.h>
+
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+#include <asm/mmu_context.h>
+#include <asm/page.h>
+#include <asm/initialize_mmu.h>
+#include <asm/io.h>
+
+#if defined(CONFIG_HIGHMEM)
+static void * __init init_pmd(unsigned long vaddr, unsigned long n_pages)
+{
+	pgd_t *pgd = pgd_offset_k(vaddr);
+	pmd_t *pmd = pmd_offset(pgd, vaddr);
+	pte_t *pte;
+	unsigned long i;
+
+	n_pages = ALIGN(n_pages, PTRS_PER_PTE);
+
+	pr_debug("%s: vaddr: 0x%08lx, n_pages: %ld\n",
+		 __func__, vaddr, n_pages);
+
+	pte = alloc_bootmem_low_pages(n_pages * sizeof(pte_t));
+
+	for (i = 0; i < n_pages; ++i)
+		pte_clear(NULL, 0, pte + i);
+
+	for (i = 0; i < n_pages; i += PTRS_PER_PTE, ++pmd) {
+		pte_t *cur_pte = pte + i;
+
+		BUG_ON(!pmd_none(*pmd));
+		set_pmd(pmd, __pmd(((unsigned long)cur_pte) & PAGE_MASK));
+		BUG_ON(cur_pte != pte_offset_kernel(pmd, 0));
+		pr_debug("%s: pmd: 0x%p, pte: 0x%p\n",
+			 __func__, pmd, cur_pte);
+	}
+	return pte;
+}
+
+static void __init fixedrange_init(void)
+{
+	init_pmd(__fix_to_virt(0), __end_of_fixed_addresses);
+}
+#endif
+
+void __init paging_init(void)
+{
+#ifdef CONFIG_HIGHMEM
+	fixedrange_init();
+	pkmap_page_table = init_pmd(PKMAP_BASE, LAST_PKMAP);
+	kmap_init();
+#endif
+}
+
+/*
+ * Flush the mmu and reset associated register to default values.
+ */
+void init_mmu(void)
+{
+#if !(XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY)
+	/*
+	 * Writing zeros to the instruction and data TLBCFG special
+	 * registers ensure that valid values exist in the register.
+	 *
+	 * For existing PGSZID<w> fields, zero selects the first element
+	 * of the page-size array.  For nonexistent PGSZID<w> fields,
+	 * zero is the best value to write.  Also, when changing PGSZID<w>
+	 * fields, the corresponding TLB must be flushed.
+	 */
+	set_itlbcfg_register(0);
+	set_dtlbcfg_register(0);
+#endif
+	init_kio();
+	local_flush_tlb_all();
+
+	/* Set rasid register to a known value. */
+
+	set_rasid_register(ASID_INSERT(ASID_USER_FIRST));
+
+	/* Set PTEVADDR special register to the start of the page
+	 * table, which is in kernel mappable space (ie. not
+	 * statically mapped).  This register's value is undefined on
+	 * reset.
+	 */
+	set_ptevaddr_register(XCHAL_PAGE_TABLE_VADDR);
+}
+
+void init_kio(void)
+{
+#if XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY && defined(CONFIG_USE_OF)
+	/*
+	 * Update the IO area mapping in case xtensa_kio_paddr has changed
+	 */
+	write_dtlb_entry(__pte(xtensa_kio_paddr + CA_WRITEBACK),
+			XCHAL_KIO_CACHED_VADDR + 6);
+	write_itlb_entry(__pte(xtensa_kio_paddr + CA_WRITEBACK),
+			XCHAL_KIO_CACHED_VADDR + 6);
+	write_dtlb_entry(__pte(xtensa_kio_paddr + CA_BYPASS),
+			XCHAL_KIO_BYPASS_VADDR + 6);
+	write_itlb_entry(__pte(xtensa_kio_paddr + CA_BYPASS),
+			XCHAL_KIO_BYPASS_VADDR + 6);
+#endif
+}
-- 
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