iommu: Allow io-pgtable to be used outside of drivers/iommu/

Move io-pgtable.h to include/linux/ and export alloc_io_pgtable_ops
and free_io_pgtable_ops. This enables drivers outside drivers/iommu/ to
use the page table library. Specifically, some ARM Mali GPUs use the
ARM page table formats.

Cc: Will Deacon <will.deacon@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: iommu@lists.linux-foundation.org
Cc: linux-mediatek@lists.infradead.org
Cc: linux-arm-msm@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

1 files changed, 213 insertions, 0 deletions

diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h
new file mode 100644
index 000000000000..47d5ae559329
--- /dev/null
+++ b/include/linux/io-pgtable.h
@@ -0,0 +1,213 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __IO_PGTABLE_H
+#define __IO_PGTABLE_H
+#include <linux/bitops.h>
+
+/*
+ * Public API for use by IOMMU drivers
+ */
+enum io_pgtable_fmt {
+	ARM_32_LPAE_S1,
+	ARM_32_LPAE_S2,
+	ARM_64_LPAE_S1,
+	ARM_64_LPAE_S2,
+	ARM_V7S,
+	IO_PGTABLE_NUM_FMTS,
+};
+
+/**
+ * struct iommu_gather_ops - IOMMU callbacks for TLB and page table management.
+ *
+ * @tlb_flush_all: Synchronously invalidate the entire TLB context.
+ * @tlb_add_flush: Queue up a TLB invalidation for a virtual address range.
+ * @tlb_sync:      Ensure any queued TLB invalidation has taken effect, and
+ *                 any corresponding page table updates are visible to the
+ *                 IOMMU.
+ *
+ * Note that these can all be called in atomic context and must therefore
+ * not block.
+ */
+struct iommu_gather_ops {
+	void (*tlb_flush_all)(void *cookie);
+	void (*tlb_add_flush)(unsigned long iova, size_t size, size_t granule,
+			      bool leaf, void *cookie);
+	void (*tlb_sync)(void *cookie);
+};
+
+/**
+ * struct io_pgtable_cfg - Configuration data for a set of page tables.
+ *
+ * @quirks:        A bitmap of hardware quirks that require some special
+ *                 action by the low-level page table allocator.
+ * @pgsize_bitmap: A bitmap of page sizes supported by this set of page
+ *                 tables.
+ * @ias:           Input address (iova) size, in bits.
+ * @oas:           Output address (paddr) size, in bits.
+ * @tlb:           TLB management callbacks for this set of tables.
+ * @iommu_dev:     The device representing the DMA configuration for the
+ *                 page table walker.
+ */
+struct io_pgtable_cfg {
+	/*
+	 * IO_PGTABLE_QUIRK_ARM_NS: (ARM formats) Set NS and NSTABLE bits in
+	 *	stage 1 PTEs, for hardware which insists on validating them
+	 *	even in	non-secure state where they should normally be ignored.
+	 *
+	 * IO_PGTABLE_QUIRK_NO_PERMS: Ignore the IOMMU_READ, IOMMU_WRITE and
+	 *	IOMMU_NOEXEC flags and map everything with full access, for
+	 *	hardware which does not implement the permissions of a given
+	 *	format, and/or requires some format-specific default value.
+	 *
+	 * IO_PGTABLE_QUIRK_TLBI_ON_MAP: If the format forbids caching invalid
+	 *	(unmapped) entries but the hardware might do so anyway, perform
+	 *	TLB maintenance when mapping as well as when unmapping.
+	 *
+	 * IO_PGTABLE_QUIRK_ARM_MTK_4GB: (ARM v7s format) Set bit 9 in all
+	 *	PTEs, for Mediatek IOMMUs which treat it as a 33rd address bit
+	 *	when the SoC is in "4GB mode" and they can only access the high
+	 *	remap of DRAM (0x1_00000000 to 0x1_ffffffff).
+	 *
+	 * IO_PGTABLE_QUIRK_NO_DMA: Guarantees that the tables will only ever
+	 *	be accessed by a fully cache-coherent IOMMU or CPU (e.g. for a
+	 *	software-emulated IOMMU), such that pagetable updates need not
+	 *	be treated as explicit DMA data.
+	 *
+	 * IO_PGTABLE_QUIRK_NON_STRICT: Skip issuing synchronous leaf TLBIs
+	 *	on unmap, for DMA domains using the flush queue mechanism for
+	 *	delayed invalidation.
+	 */
+	#define IO_PGTABLE_QUIRK_ARM_NS		BIT(0)
+	#define IO_PGTABLE_QUIRK_NO_PERMS	BIT(1)
+	#define IO_PGTABLE_QUIRK_TLBI_ON_MAP	BIT(2)
+	#define IO_PGTABLE_QUIRK_ARM_MTK_4GB	BIT(3)
+	#define IO_PGTABLE_QUIRK_NO_DMA		BIT(4)
+	#define IO_PGTABLE_QUIRK_NON_STRICT	BIT(5)
+	unsigned long			quirks;
+	unsigned long			pgsize_bitmap;
+	unsigned int			ias;
+	unsigned int			oas;
+	const struct iommu_gather_ops	*tlb;
+	struct device			*iommu_dev;
+
+	/* Low-level data specific to the table format */
+	union {
+		struct {
+			u64	ttbr[2];
+			u64	tcr;
+			u64	mair[2];
+		} arm_lpae_s1_cfg;
+
+		struct {
+			u64	vttbr;
+			u64	vtcr;
+		} arm_lpae_s2_cfg;
+
+		struct {
+			u32	ttbr[2];
+			u32	tcr;
+			u32	nmrr;
+			u32	prrr;
+		} arm_v7s_cfg;
+	};
+};
+
+/**
+ * struct io_pgtable_ops - Page table manipulation API for IOMMU drivers.
+ *
+ * @map:          Map a physically contiguous memory region.
+ * @unmap:        Unmap a physically contiguous memory region.
+ * @iova_to_phys: Translate iova to physical address.
+ *
+ * These functions map directly onto the iommu_ops member functions with
+ * the same names.
+ */
+struct io_pgtable_ops {
+	int (*map)(struct io_pgtable_ops *ops, unsigned long iova,
+		   phys_addr_t paddr, size_t size, int prot);
+	size_t (*unmap)(struct io_pgtable_ops *ops, unsigned long iova,
+			size_t size);
+	phys_addr_t (*iova_to_phys)(struct io_pgtable_ops *ops,
+				    unsigned long iova);
+};
+
+/**
+ * alloc_io_pgtable_ops() - Allocate a page table allocator for use by an IOMMU.
+ *
+ * @fmt:    The page table format.
+ * @cfg:    The page table configuration. This will be modified to represent
+ *          the configuration actually provided by the allocator (e.g. the
+ *          pgsize_bitmap may be restricted).
+ * @cookie: An opaque token provided by the IOMMU driver and passed back to
+ *          the callback routines in cfg->tlb.
+ */
+struct io_pgtable_ops *alloc_io_pgtable_ops(enum io_pgtable_fmt fmt,
+					    struct io_pgtable_cfg *cfg,
+					    void *cookie);
+
+/**
+ * free_io_pgtable_ops() - Free an io_pgtable_ops structure. The caller
+ *                         *must* ensure that the page table is no longer
+ *                         live, but the TLB can be dirty.
+ *
+ * @ops: The ops returned from alloc_io_pgtable_ops.
+ */
+void free_io_pgtable_ops(struct io_pgtable_ops *ops);
+
+
+/*
+ * Internal structures for page table allocator implementations.
+ */
+
+/**
+ * struct io_pgtable - Internal structure describing a set of page tables.
+ *
+ * @fmt:    The page table format.
+ * @cookie: An opaque token provided by the IOMMU driver and passed back to
+ *          any callback routines.
+ * @cfg:    A copy of the page table configuration.
+ * @ops:    The page table operations in use for this set of page tables.
+ */
+struct io_pgtable {
+	enum io_pgtable_fmt	fmt;
+	void			*cookie;
+	struct io_pgtable_cfg	cfg;
+	struct io_pgtable_ops	ops;
+};
+
+#define io_pgtable_ops_to_pgtable(x) container_of((x), struct io_pgtable, ops)
+
+static inline void io_pgtable_tlb_flush_all(struct io_pgtable *iop)
+{
+	iop->cfg.tlb->tlb_flush_all(iop->cookie);
+}
+
+static inline void io_pgtable_tlb_add_flush(struct io_pgtable *iop,
+		unsigned long iova, size_t size, size_t granule, bool leaf)
+{
+	iop->cfg.tlb->tlb_add_flush(iova, size, granule, leaf, iop->cookie);
+}
+
+static inline void io_pgtable_tlb_sync(struct io_pgtable *iop)
+{
+	iop->cfg.tlb->tlb_sync(iop->cookie);
+}
+
+/**
+ * struct io_pgtable_init_fns - Alloc/free a set of page tables for a
+ *                              particular format.
+ *
+ * @alloc: Allocate a set of page tables described by cfg.
+ * @free:  Free the page tables associated with iop.
+ */
+struct io_pgtable_init_fns {
+	struct io_pgtable *(*alloc)(struct io_pgtable_cfg *cfg, void *cookie);
+	void (*free)(struct io_pgtable *iop);
+};
+
+extern struct io_pgtable_init_fns io_pgtable_arm_32_lpae_s1_init_fns;
+extern struct io_pgtable_init_fns io_pgtable_arm_32_lpae_s2_init_fns;
+extern struct io_pgtable_init_fns io_pgtable_arm_64_lpae_s1_init_fns;
+extern struct io_pgtable_init_fns io_pgtable_arm_64_lpae_s2_init_fns;
+extern struct io_pgtable_init_fns io_pgtable_arm_v7s_init_fns;
+
+#endif /* __IO_PGTABLE_H */