iommu: Add driver for Renesas VMSA-compatible IPMMU

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

1 files changed, 1070 insertions, 0 deletions

diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
new file mode 100644
index 000000000000..b084530babf4
--- /dev/null
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -0,0 +1,1070 @@
+/*
+ * IPMMU VMSA
+ *
+ * Copyright (C) 2014 Renesas Electronics 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; version 2 of the License.
+ */
+
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iommu.h>
+#include <linux/module.h>
+#include <linux/platform_data/ipmmu-vmsa.h>
+#include <linux/platform_device.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+
+#include <asm/dma-iommu.h>
+#include <asm/pgalloc.h>
+
+struct ipmmu_vmsa_device {
+	struct device *dev;
+	void __iomem *base;
+	struct list_head list;
+
+	const struct ipmmu_vmsa_platform_data *pdata;
+	unsigned int num_utlbs;
+
+	struct dma_iommu_mapping *mapping;
+};
+
+struct ipmmu_vmsa_domain {
+	struct ipmmu_vmsa_device *mmu;
+	struct iommu_domain *io_domain;
+
+	unsigned int context_id;
+	spinlock_t lock;			/* Protects mappings */
+	pgd_t *pgd;
+};
+
+static DEFINE_SPINLOCK(ipmmu_devices_lock);
+static LIST_HEAD(ipmmu_devices);
+
+#define TLB_LOOP_TIMEOUT		100	/* 100us */
+
+/* -----------------------------------------------------------------------------
+ * Registers Definition
+ */
+
+#define IM_CTX_SIZE			0x40
+
+#define IMCTR				0x0000
+#define IMCTR_TRE			(1 << 17)
+#define IMCTR_AFE			(1 << 16)
+#define IMCTR_RTSEL_MASK		(3 << 4)
+#define IMCTR_RTSEL_SHIFT		4
+#define IMCTR_TREN			(1 << 3)
+#define IMCTR_INTEN			(1 << 2)
+#define IMCTR_FLUSH			(1 << 1)
+#define IMCTR_MMUEN			(1 << 0)
+
+#define IMCAAR				0x0004
+
+#define IMTTBCR				0x0008
+#define IMTTBCR_EAE			(1 << 31)
+#define IMTTBCR_PMB			(1 << 30)
+#define IMTTBCR_SH1_NON_SHAREABLE	(0 << 28)
+#define IMTTBCR_SH1_OUTER_SHAREABLE	(2 << 28)
+#define IMTTBCR_SH1_INNER_SHAREABLE	(3 << 28)
+#define IMTTBCR_SH1_MASK		(3 << 28)
+#define IMTTBCR_ORGN1_NC		(0 << 26)
+#define IMTTBCR_ORGN1_WB_WA		(1 << 26)
+#define IMTTBCR_ORGN1_WT		(2 << 26)
+#define IMTTBCR_ORGN1_WB		(3 << 26)
+#define IMTTBCR_ORGN1_MASK		(3 << 26)
+#define IMTTBCR_IRGN1_NC		(0 << 24)
+#define IMTTBCR_IRGN1_WB_WA		(1 << 24)
+#define IMTTBCR_IRGN1_WT		(2 << 24)
+#define IMTTBCR_IRGN1_WB		(3 << 24)
+#define IMTTBCR_IRGN1_MASK		(3 << 24)
+#define IMTTBCR_TSZ1_MASK		(7 << 16)
+#define IMTTBCR_TSZ1_SHIFT		16
+#define IMTTBCR_SH0_NON_SHAREABLE	(0 << 12)
+#define IMTTBCR_SH0_OUTER_SHAREABLE	(2 << 12)
+#define IMTTBCR_SH0_INNER_SHAREABLE	(3 << 12)
+#define IMTTBCR_SH0_MASK		(3 << 12)
+#define IMTTBCR_ORGN0_NC		(0 << 10)
+#define IMTTBCR_ORGN0_WB_WA		(1 << 10)
+#define IMTTBCR_ORGN0_WT		(2 << 10)
+#define IMTTBCR_ORGN0_WB		(3 << 10)
+#define IMTTBCR_ORGN0_MASK		(3 << 10)
+#define IMTTBCR_IRGN0_NC		(0 << 8)
+#define IMTTBCR_IRGN0_WB_WA		(1 << 8)
+#define IMTTBCR_IRGN0_WT		(2 << 8)
+#define IMTTBCR_IRGN0_WB		(3 << 8)
+#define IMTTBCR_IRGN0_MASK		(3 << 8)
+#define IMTTBCR_SL0_LVL_2		(0 << 4)
+#define IMTTBCR_SL0_LVL_1		(1 << 4)
+#define IMTTBCR_TSZ0_MASK		(7 << 0)
+#define IMTTBCR_TSZ0_SHIFT		O
+
+#define IMBUSCR				0x000c
+#define IMBUSCR_DVM			(1 << 2)
+#define IMBUSCR_BUSSEL_SYS		(0 << 0)
+#define IMBUSCR_BUSSEL_CCI		(1 << 0)
+#define IMBUSCR_BUSSEL_IMCAAR		(2 << 0)
+#define IMBUSCR_BUSSEL_CCI_IMCAAR	(3 << 0)
+#define IMBUSCR_BUSSEL_MASK		(3 << 0)
+
+#define IMTTLBR0			0x0010
+#define IMTTUBR0			0x0014
+#define IMTTLBR1			0x0018
+#define IMTTUBR1			0x001c
+
+#define IMSTR				0x0020
+#define IMSTR_ERRLVL_MASK		(3 << 12)
+#define IMSTR_ERRLVL_SHIFT		12
+#define IMSTR_ERRCODE_TLB_FORMAT	(1 << 8)
+#define IMSTR_ERRCODE_ACCESS_PERM	(4 << 8)
+#define IMSTR_ERRCODE_SECURE_ACCESS	(5 << 8)
+#define IMSTR_ERRCODE_MASK		(7 << 8)
+#define IMSTR_MHIT			(1 << 4)
+#define IMSTR_ABORT			(1 << 2)
+#define IMSTR_PF			(1 << 1)
+#define IMSTR_TF			(1 << 0)
+
+#define IMMAIR0				0x0028
+#define IMMAIR1				0x002c
+#define IMMAIR_ATTR_MASK		0xff
+#define IMMAIR_ATTR_DEVICE		0x04
+#define IMMAIR_ATTR_NC			0x44
+#define IMMAIR_ATTR_WBRWA		0xff
+#define IMMAIR_ATTR_SHIFT(n)		((n) << 3)
+#define IMMAIR_ATTR_IDX_NC		0
+#define IMMAIR_ATTR_IDX_WBRWA		1
+#define IMMAIR_ATTR_IDX_DEV		2
+
+#define IMEAR				0x0030
+
+#define IMPCTR				0x0200
+#define IMPSTR				0x0208
+#define IMPEAR				0x020c
+#define IMPMBA(n)			(0x0280 + ((n) * 4))
+#define IMPMBD(n)			(0x02c0 + ((n) * 4))
+
+#define IMUCTR(n)			(0x0300 + ((n) * 16))
+#define IMUCTR_FIXADDEN			(1 << 31)
+#define IMUCTR_FIXADD_MASK		(0xff << 16)
+#define IMUCTR_FIXADD_SHIFT		16
+#define IMUCTR_TTSEL_MMU(n)		((n) << 4)
+#define IMUCTR_TTSEL_PMB		(8 << 4)
+#define IMUCTR_TTSEL_MASK		(15 << 4)
+#define IMUCTR_FLUSH			(1 << 1)
+#define IMUCTR_MMUEN			(1 << 0)
+
+#define IMUASID(n)			(0x0308 + ((n) * 16))
+#define IMUASID_ASID8_MASK		(0xff << 8)
+#define IMUASID_ASID8_SHIFT		8
+#define IMUASID_ASID0_MASK		(0xff << 0)
+#define IMUASID_ASID0_SHIFT		0
+
+/* -----------------------------------------------------------------------------
+ * Page Table Bits
+ */
+
+/*
+ * VMSA states in section B3.6.3 "Control of Secure or Non-secure memory access,
+ * Long-descriptor format" that the NStable bit being set in a table descriptor
+ * will result in the NStable and NS bits of all child entries being ignored and
+ * considered as being set. The IPMMU seems not to comply with this, as it
+ * generates a secure access page fault if any of the NStable and NS bits isn't
+ * set when running in non-secure mode.
+ */
+#ifndef PMD_NSTABLE
+#define PMD_NSTABLE			(_AT(pmdval_t, 1) << 63)
+#endif
+
+#define ARM_VMSA_PTE_XN			(((pteval_t)3) << 53)
+#define ARM_VMSA_PTE_CONT		(((pteval_t)1) << 52)
+#define ARM_VMSA_PTE_AF			(((pteval_t)1) << 10)
+#define ARM_VMSA_PTE_SH_NS		(((pteval_t)0) << 8)
+#define ARM_VMSA_PTE_SH_OS		(((pteval_t)2) << 8)
+#define ARM_VMSA_PTE_SH_IS		(((pteval_t)3) << 8)
+#define ARM_VMSA_PTE_NS			(((pteval_t)1) << 5)
+#define ARM_VMSA_PTE_PAGE		(((pteval_t)3) << 0)
+
+/* Stage-1 PTE */
+#define ARM_VMSA_PTE_AP_UNPRIV		(((pteval_t)1) << 6)
+#define ARM_VMSA_PTE_AP_RDONLY		(((pteval_t)2) << 6)
+#define ARM_VMSA_PTE_ATTRINDX_SHIFT	2
+#define ARM_VMSA_PTE_nG			(((pteval_t)1) << 11)
+
+/* Stage-2 PTE */
+#define ARM_VMSA_PTE_HAP_FAULT		(((pteval_t)0) << 6)
+#define ARM_VMSA_PTE_HAP_READ		(((pteval_t)1) << 6)
+#define ARM_VMSA_PTE_HAP_WRITE		(((pteval_t)2) << 6)
+#define ARM_VMSA_PTE_MEMATTR_OIWB	(((pteval_t)0xf) << 2)
+#define ARM_VMSA_PTE_MEMATTR_NC		(((pteval_t)0x5) << 2)
+#define ARM_VMSA_PTE_MEMATTR_DEV	(((pteval_t)0x1) << 2)
+
+/* -----------------------------------------------------------------------------
+ * Read/Write Access
+ */
+
+static u32 ipmmu_read(struct ipmmu_vmsa_device *mmu, unsigned int offset)
+{
+	return ioread32(mmu->base + offset);
+}
+
+static void ipmmu_write(struct ipmmu_vmsa_device *mmu, unsigned int offset,
+			u32 data)
+{
+	iowrite32(data, mmu->base + offset);
+}
+
+static u32 ipmmu_ctx_read(struct ipmmu_vmsa_domain *domain, unsigned int reg)
+{
+	return ipmmu_read(domain->mmu, domain->context_id * IM_CTX_SIZE + reg);
+}
+
+static void ipmmu_ctx_write(struct ipmmu_vmsa_domain *domain, unsigned int reg,
+			    u32 data)
+{
+	ipmmu_write(domain->mmu, domain->context_id * IM_CTX_SIZE + reg, data);
+}
+
+/* -----------------------------------------------------------------------------
+ * TLB and microTLB Management
+ */
+
+/* Wait for any pending TLB invalidations to complete */
+static void ipmmu_tlb_sync(struct ipmmu_vmsa_domain *domain)
+{
+	unsigned int count = 0;
+
+	while (ipmmu_ctx_read(domain, IMCTR) & IMCTR_FLUSH) {
+		cpu_relax();
+		if (++count == TLB_LOOP_TIMEOUT) {
+			dev_err_ratelimited(domain->mmu->dev,
+			"TLB sync timed out -- MMU may be deadlocked\n");
+			return;
+		}
+		udelay(1);
+	}
+}
+
+static void ipmmu_tlb_invalidate(struct ipmmu_vmsa_domain *domain)
+{
+	u32 reg;
+
+	reg = ipmmu_ctx_read(domain, IMCTR);
+	reg |= IMCTR_FLUSH;
+	ipmmu_ctx_write(domain, IMCTR, reg);
+
+	ipmmu_tlb_sync(domain);
+}
+
+/*
+ * Enable MMU translation for the microTLB.
+ */
+static void ipmmu_utlb_enable(struct ipmmu_vmsa_domain *domain,
+			      const struct ipmmu_vmsa_master *master)
+{
+	struct ipmmu_vmsa_device *mmu = domain->mmu;
+
+	/* TODO: What should we set the ASID to ? */
+	ipmmu_write(mmu, IMUASID(master->utlb), 0);
+	/* TODO: Do we need to flush the microTLB ? */
+	ipmmu_write(mmu, IMUCTR(master->utlb),
+		    IMUCTR_TTSEL_MMU(domain->context_id) | IMUCTR_FLUSH |
+		    IMUCTR_MMUEN);
+}
+
+/*
+ * Disable MMU translation for the microTLB.
+ */
+static void ipmmu_utlb_disable(struct ipmmu_vmsa_domain *domain,
+			       const struct ipmmu_vmsa_master *master)
+{
+	struct ipmmu_vmsa_device *mmu = domain->mmu;
+
+	ipmmu_write(mmu, IMUCTR(master->utlb), 0);
+}
+
+static void ipmmu_flush_pgtable(struct ipmmu_vmsa_device *mmu, void *addr,
+				size_t size)
+{
+	unsigned long offset = (unsigned long)addr & ~PAGE_MASK;
+
+	/*
+	 * TODO: Add support for coherent walk through CCI with DVM and remove
+	 * cache handling.
+	 */
+	dma_map_page(mmu->dev, virt_to_page(addr), offset, size, DMA_TO_DEVICE);
+}
+
+/* -----------------------------------------------------------------------------
+ * Domain/Context Management
+ */
+
+static int ipmmu_domain_init_context(struct ipmmu_vmsa_domain *domain)
+{
+	phys_addr_t ttbr;
+	u32 reg;
+
+	/*
+	 * TODO: When adding support for multiple contexts, find an unused
+	 * context.
+	 */
+	domain->context_id = 0;
+
+	/* TTBR0 */
+	ipmmu_flush_pgtable(domain->mmu, domain->pgd,
+			    PTRS_PER_PGD * sizeof(*domain->pgd));
+	ttbr = __pa(domain->pgd);
+	ipmmu_ctx_write(domain, IMTTLBR0, ttbr);
+	ipmmu_ctx_write(domain, IMTTUBR0, ttbr >> 32);
+
+	/*
+	 * TTBCR
+	 * We use long descriptors with inner-shareable WBWA tables and allocate
+	 * the whole 32-bit VA space to TTBR0.
+	 */
+	ipmmu_ctx_write(domain, IMTTBCR, IMTTBCR_EAE |
+			IMTTBCR_SH0_INNER_SHAREABLE | IMTTBCR_ORGN0_WB_WA |
+			IMTTBCR_IRGN0_WB_WA | IMTTBCR_SL0_LVL_1);
+
+	/*
+	 * MAIR0
+	 * We need three attributes only, non-cacheable, write-back read/write
+	 * allocate and device memory.
+	 */
+	reg = (IMMAIR_ATTR_NC << IMMAIR_ATTR_SHIFT(IMMAIR_ATTR_IDX_NC))
+	    | (IMMAIR_ATTR_WBRWA << IMMAIR_ATTR_SHIFT(IMMAIR_ATTR_IDX_WBRWA))
+	    | (IMMAIR_ATTR_DEVICE << IMMAIR_ATTR_SHIFT(IMMAIR_ATTR_IDX_DEV));
+	ipmmu_ctx_write(domain, IMMAIR0, reg);
+
+	/* IMBUSCR */
+	ipmmu_ctx_write(domain, IMBUSCR,
+			ipmmu_ctx_read(domain, IMBUSCR) &
+			~(IMBUSCR_DVM | IMBUSCR_BUSSEL_MASK));
+
+	/*
+	 * IMSTR
+	 * Clear all interrupt flags.
+	 */
+	ipmmu_ctx_write(domain, IMSTR, ipmmu_ctx_read(domain, IMSTR));
+
+	/*
+	 * IMCTR
+	 * Enable the MMU and interrupt generation. The long-descriptor
+	 * translation table format doesn't use TEX remapping. Don't enable AF
+	 * software management as we have no use for it. Flush the TLB as
+	 * required when modifying the context registers.
+	 */
+	ipmmu_ctx_write(domain, IMCTR, IMCTR_INTEN | IMCTR_FLUSH | IMCTR_MMUEN);
+
+	return 0;
+}
+
+static void ipmmu_domain_destroy_context(struct ipmmu_vmsa_domain *domain)
+{
+	/*
+	 * Disable the context. Flush the TLB as required when modifying the
+	 * context registers.
+	 *
+	 * TODO: Is TLB flush really needed ?
+	 */
+	ipmmu_ctx_write(domain, IMCTR, IMCTR_FLUSH);
+	ipmmu_tlb_sync(domain);
+}
+
+/* -----------------------------------------------------------------------------
+ * Fault Handling
+ */
+
+static irqreturn_t ipmmu_domain_irq(struct ipmmu_vmsa_domain *domain)
+{
+	const u32 err_mask = IMSTR_MHIT | IMSTR_ABORT | IMSTR_PF | IMSTR_TF;
+	struct ipmmu_vmsa_device *mmu = domain->mmu;
+	u32 status;
+	u32 iova;
+
+	status = ipmmu_ctx_read(domain, IMSTR);
+	if (!(status & err_mask))
+		return IRQ_NONE;
+
+	iova = ipmmu_ctx_read(domain, IMEAR);
+
+	/*
+	 * Clear the error status flags. Unlike traditional interrupt flag
+	 * registers that must be cleared by writing 1, this status register
+	 * seems to require 0. The error address register must be read before,
+	 * otherwise its value will be 0.
+	 */
+	ipmmu_ctx_write(domain, IMSTR, 0);
+
+	/* Log fatal errors. */
+	if (status & IMSTR_MHIT)
+		dev_err_ratelimited(mmu->dev, "Multiple TLB hits @0x%08x\n",
+				    iova);
+	if (status & IMSTR_ABORT)
+		dev_err_ratelimited(mmu->dev, "Page Table Walk Abort @0x%08x\n",
+				    iova);
+
+	if (!(status & (IMSTR_PF | IMSTR_TF)))
+		return IRQ_NONE;
+
+	/*
+	 * Try to handle page faults and translation faults.
+	 *
+	 * TODO: We need to look up the faulty device based on the I/O VA. Use
+	 * the IOMMU device for now.
+	 */
+	if (!report_iommu_fault(domain->io_domain, mmu->dev, iova, 0))
+		return IRQ_HANDLED;
+
+	dev_err_ratelimited(mmu->dev,
+			    "Unhandled fault: status 0x%08x iova 0x%08x\n",
+			    status, iova);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t ipmmu_irq(int irq, void *dev)
+{
+	struct ipmmu_vmsa_device *mmu = dev;
+	struct iommu_domain *io_domain;
+	struct ipmmu_vmsa_domain *domain;
+
+	if (!mmu->mapping)
+		return IRQ_NONE;
+
+	io_domain = mmu->mapping->domain;
+	domain = io_domain->priv;
+
+	return ipmmu_domain_irq(domain);
+}
+
+/* -----------------------------------------------------------------------------
+ * Page Table Management
+ */
+
+static void ipmmu_free_ptes(pmd_t *pmd)
+{
+	pgtable_t table = pmd_pgtable(*pmd);
+	__free_page(table);
+}
+
+static void ipmmu_free_pmds(pud_t *pud)
+{
+	pmd_t *pmd, *pmd_base = pmd_offset(pud, 0);
+	unsigned int i;
+
+	pmd = pmd_base;
+	for (i = 0; i < PTRS_PER_PMD; ++i) {
+		if (pmd_none(*pmd))
+			continue;
+
+		ipmmu_free_ptes(pmd);
+		pmd++;
+	}
+
+	pmd_free(NULL, pmd_base);
+}
+
+static void ipmmu_free_puds(pgd_t *pgd)
+{
+	pud_t *pud, *pud_base = pud_offset(pgd, 0);
+	unsigned int i;
+
+	pud = pud_base;
+	for (i = 0; i < PTRS_PER_PUD; ++i) {
+		if (pud_none(*pud))
+			continue;
+
+		ipmmu_free_pmds(pud);
+		pud++;
+	}
+
+	pud_free(NULL, pud_base);
+}
+
+static void ipmmu_free_pgtables(struct ipmmu_vmsa_domain *domain)
+{
+	pgd_t *pgd, *pgd_base = domain->pgd;
+	unsigned int i;
+
+	/*
+	 * Recursively free the page tables for this domain. We don't care about
+	 * speculative TLB filling, because the TLB will be nuked next time this
+	 * context bank is re-allocated and no devices currently map to these
+	 * tables.
+	 */
+	pgd = pgd_base;
+	for (i = 0; i < PTRS_PER_PGD; ++i) {
+		if (pgd_none(*pgd))
+			continue;
+		ipmmu_free_puds(pgd);
+		pgd++;
+	}
+
+	kfree(pgd_base);
+}
+
+/*
+ * We can't use the (pgd|pud|pmd|pte)_populate or the set_(pgd|pud|pmd|pte)
+ * functions as they would flush the CPU TLB.
+ */
+
+static int ipmmu_alloc_init_pte(struct ipmmu_vmsa_device *mmu, pmd_t *pmd,
+				unsigned long addr, unsigned long end,
+				phys_addr_t phys, int prot)
+{
+	unsigned long pfn = __phys_to_pfn(phys);
+	pteval_t pteval = ARM_VMSA_PTE_PAGE | ARM_VMSA_PTE_NS | ARM_VMSA_PTE_AF
+			| ARM_VMSA_PTE_XN;
+	pte_t *pte, *start;
+
+	if (pmd_none(*pmd)) {
+		/* Allocate a new set of tables */
+		pte = (pte_t *)get_zeroed_page(GFP_ATOMIC);
+		if (!pte)
+			return -ENOMEM;
+
+		ipmmu_flush_pgtable(mmu, pte, PAGE_SIZE);
+		*pmd = __pmd(__pa(pte) | PMD_NSTABLE | PMD_TYPE_TABLE);
+		ipmmu_flush_pgtable(mmu, pmd, sizeof(*pmd));
+
+		pte += pte_index(addr);
+	} else
+		pte = pte_offset_kernel(pmd, addr);
+
+	pteval |= ARM_VMSA_PTE_AP_UNPRIV | ARM_VMSA_PTE_nG;
+	if (!(prot & IOMMU_WRITE) && (prot & IOMMU_READ))
+		pteval |= ARM_VMSA_PTE_AP_RDONLY;
+
+	if (prot & IOMMU_CACHE)
+		pteval |= (IMMAIR_ATTR_IDX_WBRWA <<
+			   ARM_VMSA_PTE_ATTRINDX_SHIFT);
+
+	/* If no access, create a faulting entry to avoid TLB fills */
+	if (prot & IOMMU_EXEC)
+		pteval &= ~ARM_VMSA_PTE_XN;
+	else if (!(prot & (IOMMU_READ | IOMMU_WRITE)))
+		pteval &= ~ARM_VMSA_PTE_PAGE;
+
+	pteval |= ARM_VMSA_PTE_SH_IS;
+	start = pte;
+
+	/* Install the page table entries. */
+	do {
+		*pte++ = pfn_pte(pfn++, __pgprot(pteval));
+		addr += PAGE_SIZE;
+	} while (addr != end);
+
+	ipmmu_flush_pgtable(mmu, start, sizeof(*pte) * (pte - start));
+	return 0;
+}
+
+static int ipmmu_alloc_init_pmd(struct ipmmu_vmsa_device *mmu, pud_t *pud,
+				unsigned long addr, unsigned long end,
+				phys_addr_t phys, int prot)
+{
+	unsigned long next;
+	pmd_t *pmd;
+	int ret;
+
+#ifndef __PAGETABLE_PMD_FOLDED
+	if (pud_none(*pud)) {
+		pmd = (pmd_t *)get_zeroed_page(GFP_ATOMIC);
+		if (!pmd)
+			return -ENOMEM;
+
+		ipmmu_flush_pgtable(mmu, pmd, PAGE_SIZE);
+		*pud = __pud(__pa(pmd) | PMD_NSTABLE | PMD_TYPE_TABLE);
+		ipmmu_flush_pgtable(mmu, pud, sizeof(*pud));
+
+		pmd += pmd_index(addr);
+	} else
+#endif
+		pmd = pmd_offset(pud, addr);
+
+	do {
+		next = pmd_addr_end(addr, end);
+		ret = ipmmu_alloc_init_pte(mmu, pmd, addr, end, phys, prot);
+		phys += next - addr;
+	} while (pmd++, addr = next, addr < end);
+
+	return ret;
+}
+
+static int ipmmu_alloc_init_pud(struct ipmmu_vmsa_device *mmu, pgd_t *pgd,
+				unsigned long addr, unsigned long end,
+				phys_addr_t phys, int prot)
+{
+	unsigned long next;
+	pud_t *pud;
+	int ret;
+
+#ifndef __PAGETABLE_PUD_FOLDED
+	if (pgd_none(*pgd)) {
+		pud = (pud_t *)get_zeroed_page(GFP_ATOMIC);
+		if (!pud)
+			return -ENOMEM;
+
+		ipmmu_flush_pgtable(mmu, pud, PAGE_SIZE);
+		*pgd = __pgd(__pa(pud) | PMD_NSTABLE | PMD_TYPE_TABLE);
+		ipmmu_flush_pgtable(mmu, pgd, sizeof(*pgd));
+
+		pud += pud_index(addr);
+	} else
+#endif
+		pud = pud_offset(pgd, addr);
+
+	do {
+		next = pud_addr_end(addr, end);
+		ret = ipmmu_alloc_init_pmd(mmu, pud, addr, next, phys, prot);
+		phys += next - addr;
+	} while (pud++, addr = next, addr < end);
+
+	return ret;
+}
+
+static int ipmmu_handle_mapping(struct ipmmu_vmsa_domain *domain,
+				unsigned long iova, phys_addr_t paddr,
+				size_t size, int prot)
+{
+	struct ipmmu_vmsa_device *mmu = domain->mmu;
+	pgd_t *pgd = domain->pgd;
+	unsigned long flags;
+	unsigned long end;
+	int ret;
+
+	if (!pgd)
+		return -EINVAL;
+
+	if (size & ~PAGE_MASK)
+		return -EINVAL;
+
+	if (paddr & ~((1ULL << 40) - 1))
+		return -ERANGE;
+
+	spin_lock_irqsave(&domain->lock, flags);
+
+	pgd += pgd_index(iova);
+	end = iova + size;
+
+	do {
+		unsigned long next = pgd_addr_end(iova, end);
+
+		ret = ipmmu_alloc_init_pud(mmu, pgd, iova, next, paddr, prot);
+		if (ret)
+			break;
+
+		paddr += next - iova;
+		iova = next;
+	} while (pgd++, iova != end);
+
+	spin_unlock_irqrestore(&domain->lock, flags);
+
+	ipmmu_tlb_invalidate(domain);
+
+	return ret;
+}
+
+/* -----------------------------------------------------------------------------
+ * IOMMU Operations
+ */
+
+static const struct ipmmu_vmsa_master *
+ipmmu_find_master(struct ipmmu_vmsa_device *ipmmu, struct device *dev)
+{
+	const struct ipmmu_vmsa_master *master = ipmmu->pdata->masters;
+	const char *devname = dev_name(dev);
+	unsigned int i;
+
+	for (i = 0; i < ipmmu->pdata->num_masters; ++i, ++master) {
+		if (strcmp(master->name, devname) == 0)
+			return master;
+	}
+
+	return NULL;
+}
+
+static int ipmmu_domain_init(struct iommu_domain *io_domain)
+{
+	struct ipmmu_vmsa_domain *domain;
+
+	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
+	if (!domain)
+		return -ENOMEM;
+
+	spin_lock_init(&domain->lock);
+
+	domain->pgd = kzalloc(PTRS_PER_PGD * sizeof(pgd_t), GFP_KERNEL);
+	if (!domain->pgd) {
+		kfree(domain);
+		return -ENOMEM;
+	}
+
+	io_domain->priv = domain;
+	domain->io_domain = io_domain;
+
+	return 0;
+}
+
+static void ipmmu_domain_destroy(struct iommu_domain *io_domain)
+{
+	struct ipmmu_vmsa_domain *domain = io_domain->priv;
+
+	/*
+	 * Free the domain resources. We assume that all devices have already
+	 * been detached.
+	 */
+	ipmmu_domain_destroy_context(domain);
+	ipmmu_free_pgtables(domain);
+	kfree(domain);
+}
+
+static int ipmmu_attach_device(struct iommu_domain *io_domain,
+			       struct device *dev)
+{
+	struct ipmmu_vmsa_device *mmu = dev->archdata.iommu;
+	struct ipmmu_vmsa_domain *domain = io_domain->priv;
+	const struct ipmmu_vmsa_master *master;
+	unsigned long flags;
+	int ret = 0;
+
+	if (!mmu) {
+		dev_err(dev, "Cannot attach to IPMMU\n");
+		return -ENXIO;
+	}
+
+	spin_lock_irqsave(&domain->lock, flags);
+
+	if (!domain->mmu) {
+		/* The domain hasn't been used yet, initialize it. */
+		domain->mmu = mmu;
+		ret = ipmmu_domain_init_context(domain);
+	} else if (domain->mmu != mmu) {
+		/*
+		 * Something is wrong, we can't attach two devices using
+		 * different IOMMUs to the same domain.
+		 */
+		dev_err(dev, "Can't attach IPMMU %s to domain on IPMMU %s\n",
+			dev_name(mmu->dev), dev_name(domain->mmu->dev));
+		ret = -EINVAL;
+	}
+
+	spin_unlock_irqrestore(&domain->lock, flags);
+
+	if (ret < 0)
+		return ret;
+
+	master = ipmmu_find_master(mmu, dev);
+	if (!master)
+		return -EINVAL;
+
+	ipmmu_utlb_enable(domain, master);
+
+	return 0;
+}
+
+static void ipmmu_detach_device(struct iommu_domain *io_domain,
+				struct device *dev)
+{
+	struct ipmmu_vmsa_domain *domain = io_domain->priv;
+	const struct ipmmu_vmsa_master *master;
+
+	master = ipmmu_find_master(domain->mmu, dev);
+	if (!master)
+		return;
+
+	ipmmu_utlb_disable(domain, master);
+
+	/*
+	 * TODO: Optimize by disabling the context when no device is attached.
+	 */
+}
+
+static int ipmmu_map(struct iommu_domain *io_domain, unsigned long iova,
+		     phys_addr_t paddr, size_t size, int prot)
+{
+	struct ipmmu_vmsa_domain *domain = io_domain->priv;
+
+	if (!domain)
+		return -ENODEV;
+
+	return ipmmu_handle_mapping(domain, iova, paddr, size, prot);
+}
+
+static size_t ipmmu_unmap(struct iommu_domain *io_domain, unsigned long iova,
+			  size_t size)
+{
+	struct ipmmu_vmsa_domain *domain = io_domain->priv;
+	int ret;
+
+	ret = ipmmu_handle_mapping(domain, iova, 0, size, 0);
+	return ret ? 0 : size;
+}
+
+static phys_addr_t ipmmu_iova_to_phys(struct iommu_domain *io_domain,
+				      dma_addr_t iova)
+{
+	struct ipmmu_vmsa_domain *domain = io_domain->priv;
+	pgd_t pgd;
+	pud_t pud;
+	pmd_t pmd;
+	pte_t pte;
+
+	/* TODO: Is locking needed ? */
+
+	if (!domain->pgd)
+		return 0;
+
+	pgd = *(domain->pgd + pgd_index(iova));
+	if (pgd_none(pgd))
+		return 0;
+
+	pud = *pud_offset(&pgd, iova);
+	if (pud_none(pud))
+		return 0;
+
+	pmd = *pmd_offset(&pud, iova);
+	if (pmd_none(pmd))
+		return 0;
+
+	pte = *(pmd_page_vaddr(pmd) + pte_index(iova));
+	if (pte_none(pte))
+		return 0;
+
+	return __pfn_to_phys(pte_pfn(pte)) | (iova & ~PAGE_MASK);
+}
+
+static int ipmmu_add_device(struct device *dev)
+{
+	const struct ipmmu_vmsa_master *master = NULL;
+	struct ipmmu_vmsa_device *mmu;
+	struct iommu_group *group;
+	int ret;
+
+	if (dev->archdata.iommu) {
+		dev_warn(dev, "IOMMU driver already assigned to device %s\n",
+			 dev_name(dev));
+		return -EINVAL;
+	}
+
+	/* Find the master corresponding to the device. */
+	spin_lock(&ipmmu_devices_lock);
+
+	list_for_each_entry(mmu, &ipmmu_devices, list) {
+		master = ipmmu_find_master(mmu, dev);
+		if (master) {
+			/*
+			 * TODO Take a reference to the master to protect
+			 * against device removal.
+			 */
+			break;
+		}
+	}
+
+	spin_unlock(&ipmmu_devices_lock);
+
+	if (!master)
+		return -ENODEV;
+
+	if (!master->utlb >= mmu->num_utlbs)
+		return -EINVAL;
+
+	/* Create a device group and add the device to it. */
+	group = iommu_group_alloc();
+	if (IS_ERR(group)) {
+		dev_err(dev, "Failed to allocate IOMMU group\n");
+		return PTR_ERR(group);
+	}
+
+	ret = iommu_group_add_device(group, dev);
+	iommu_group_put(group);
+
+	if (ret < 0) {
+		dev_err(dev, "Failed to add device to IPMMU group\n");
+		return ret;
+	}
+
+	dev->archdata.iommu = mmu;
+
+	/*
+	 * Create the ARM mapping, used by the ARM DMA mapping core to allocate
+	 * VAs. This will allocate a corresponding IOMMU domain.
+	 *
+	 * TODO:
+	 * - Create one mapping per context (TLB).
+	 * - Make the mapping size configurable ? We currently use a 2GB mapping
+	 *   at a 1GB offset to ensure that NULL VAs will fault.
+	 */
+	if (!mmu->mapping) {
+		struct dma_iommu_mapping *mapping;
+
+		mapping = arm_iommu_create_mapping(&platform_bus_type,
+							SZ_1G, SZ_2G, 0);
+		if (IS_ERR(mapping)) {
+			dev_err(mmu->dev, "failed to create ARM IOMMU mapping\n");
+			return PTR_ERR(mapping);
+		}
+
+		mmu->mapping = mapping;
+	}
+
+	/* Attach the ARM VA mapping to the device. */
+	ret = arm_iommu_attach_device(dev, mmu->mapping);
+	if (ret < 0) {
+		dev_err(dev, "Failed to attach device to VA mapping\n");
+		goto error;
+	}
+
+	return 0;
+
+error:
+	dev->archdata.iommu = NULL;
+	iommu_group_remove_device(dev);
+	return ret;
+}
+
+static void ipmmu_remove_device(struct device *dev)
+{
+	arm_iommu_detach_device(dev);
+	iommu_group_remove_device(dev);
+	dev->archdata.iommu = NULL;
+}
+
+static struct iommu_ops ipmmu_ops = {
+	.domain_init = ipmmu_domain_init,
+	.domain_destroy = ipmmu_domain_destroy,
+	.attach_dev = ipmmu_attach_device,
+	.detach_dev = ipmmu_detach_device,
+	.map = ipmmu_map,
+	.unmap = ipmmu_unmap,
+	.iova_to_phys = ipmmu_iova_to_phys,
+	.add_device = ipmmu_add_device,
+	.remove_device = ipmmu_remove_device,
+	.pgsize_bitmap = SZ_1M | SZ_64K | SZ_4K,
+};
+
+/* -----------------------------------------------------------------------------
+ * Probe/remove and init
+ */
+
+static void ipmmu_device_reset(struct ipmmu_vmsa_device *mmu)
+{
+	unsigned int i;
+
+	/* Disable all contexts. */
+	for (i = 0; i < 4; ++i)
+		ipmmu_write(mmu, i * IM_CTX_SIZE + IMCTR, 0);
+}
+
+static int ipmmu_probe(struct platform_device *pdev)
+{
+	struct ipmmu_vmsa_device *mmu;
+	struct resource *res;
+	int irq;
+	int ret;
+
+	if (!pdev->dev.platform_data) {
+		dev_err(&pdev->dev, "missing platform data\n");
+		return -EINVAL;
+	}
+
+	mmu = devm_kzalloc(&pdev->dev, sizeof(*mmu), GFP_KERNEL);
+	if (!mmu) {
+		dev_err(&pdev->dev, "cannot allocate device data\n");
+		return -ENOMEM;
+	}
+
+	mmu->dev = &pdev->dev;
+	mmu->pdata = pdev->dev.platform_data;
+	mmu->num_utlbs = 32;
+
+	/* Map I/O memory and request IRQ. */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	mmu->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(mmu->base))
+		return PTR_ERR(mmu->base);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "no IRQ found\n");
+		return irq;
+	}
+
+	ret = devm_request_irq(&pdev->dev, irq, ipmmu_irq, 0,
+			       dev_name(&pdev->dev), mmu);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to request IRQ %d\n", irq);
+		return irq;
+	}
+
+	ipmmu_device_reset(mmu);
+
+	/*
+	 * We can't create the ARM mapping here as it requires the bus to have
+	 * an IOMMU, which only happens when bus_set_iommu() is called in
+	 * ipmmu_init() after the probe function returns.
+	 */
+
+	spin_lock(&ipmmu_devices_lock);
+	list_add(&mmu->list, &ipmmu_devices);
+	spin_unlock(&ipmmu_devices_lock);
+
+	platform_set_drvdata(pdev, mmu);
+
+	return 0;
+}
+
+static int ipmmu_remove(struct platform_device *pdev)
+{
+	struct ipmmu_vmsa_device *mmu = platform_get_drvdata(pdev);
+
+	spin_lock(&ipmmu_devices_lock);
+	list_del(&mmu->list);
+	spin_unlock(&ipmmu_devices_lock);
+
+	arm_iommu_release_mapping(mmu->mapping);
+
+	ipmmu_device_reset(mmu);
+
+	return 0;
+}
+
+static struct platform_driver ipmmu_driver = {
+	.driver = {
+		.owner = THIS_MODULE,
+		.name = "ipmmu-vmsa",
+	},
+	.probe = ipmmu_probe,
+	.remove	= ipmmu_remove,
+};
+
+static int __init ipmmu_init(void)
+{
+	int ret;
+
+	ret = platform_driver_register(&ipmmu_driver);
+	if (ret < 0)
+		return ret;
+
+	if (!iommu_present(&platform_bus_type))
+		bus_set_iommu(&platform_bus_type, &ipmmu_ops);
+
+	return 0;
+}
+
+static void __exit ipmmu_exit(void)
+{
+	return platform_driver_unregister(&ipmmu_driver);
+}
+
+subsys_initcall(ipmmu_init);
+module_exit(ipmmu_exit);
+
+MODULE_DESCRIPTION("IOMMU API for Renesas VMSA-compatible IPMMU");
+MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
+MODULE_LICENSE("GPL v2");