Re: [PATCH v3] iommu: Add driver for Renesas VMSA-compatible IPMMU

[Khiem Nguyen <khiem.nguyen.xt@renesas.com>]

Hi Laurent,

Thanks for the patch.

> +	if (!iommu_present(&platform_bus_type))
> +		bus_set_iommu(&platform_bus_type, &ipmmu_ops);
With this code, if error occurs, it's hidden.

I think it should be like below,

> +	ret = bus_set_iommu(&platform_bus_type, &ipmmu_ops);
> +	if (ret < 0)
> +		return ret;

In this case, if error occurs, -EBUSY is returned.
It's easier for troubleshooting the issue.

How do you think ?

Best regards,
KHIEM Nguyen

On 4/2/2014 7:47 PM, Laurent Pinchart wrote:
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> ---
>   drivers/iommu/Kconfig                    |   12 +
>   drivers/iommu/Makefile                   |    1 +
>   drivers/iommu/ipmmu-vmsa.c               | 1070 ++++++++++++++++++++++++++++++
>   include/linux/platform_data/ipmmu-vmsa.h |   24 +
>   4 files changed, 1107 insertions(+)
>   create mode 100644 drivers/iommu/ipmmu-vmsa.c
>   create mode 100644 include/linux/platform_data/ipmmu-vmsa.h
>
> Joerg, could you please take this patch in your tree for v3.16 ?
>
> Changes since v2:
>
> - Fix more typos
>
> Changes since v1:
>
> - Fix typos
>
> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index df56e4c..a22b537 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -272,6 +272,18 @@ config SHMOBILE_IOMMU_L1SIZE
>   	default 256 if SHMOBILE_IOMMU_ADDRSIZE_64MB
>   	default 128 if SHMOBILE_IOMMU_ADDRSIZE_32MB
>   
> +config IPMMU_VMSA
> +	bool "Renesas VMSA-compatible IPMMU"
> +	depends on ARM_LPAE
> +	depends on ARCH_SHMOBILE || COMPILE_TEST
> +	select IOMMU_API
> +	select ARM_DMA_USE_IOMMU
> +	help
> +	  Support for the Renesas VMSA-compatible IPMMU Renesas found in the
> +	  R-Mobile APE6 and R-Car H2/M2 SoCs.
> +
> +	  If unsure, say N.
> +
>   config SPAPR_TCE_IOMMU
>   	bool "sPAPR TCE IOMMU Support"
>   	depends on PPC_POWERNV || PPC_PSERIES
> diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
> index 5d58bf1..8893bad 100644
> --- a/drivers/iommu/Makefile
> +++ b/drivers/iommu/Makefile
> @@ -7,6 +7,7 @@ obj-$(CONFIG_AMD_IOMMU_V2) += amd_iommu_v2.o
>   obj-$(CONFIG_ARM_SMMU) += arm-smmu.o
>   obj-$(CONFIG_DMAR_TABLE) += dmar.o
>   obj-$(CONFIG_INTEL_IOMMU) += iova.o intel-iommu.o
> +obj-$(CONFIG_IPMMU_VMSA) += ipmmu-vmsa.o
>   obj-$(CONFIG_IRQ_REMAP) += intel_irq_remapping.o irq_remapping.o
>   obj-$(CONFIG_OMAP_IOMMU) += omap-iommu.o
>   obj-$(CONFIG_OMAP_IOMMU) += omap-iommu2.o
> diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
> new file mode 100644
> index 0000000..b084530
> --- /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");
> diff --git a/include/linux/platform_data/ipmmu-vmsa.h b/include/linux/platform_data/ipmmu-vmsa.h
> new file mode 100644
> index 0000000..5275b3a
> --- /dev/null
> +++ b/include/linux/platform_data/ipmmu-vmsa.h
> @@ -0,0 +1,24 @@
> +/*
> + * IPMMU VMSA Platform Data
> + *
> + * 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.
> + */
> +
> +#ifndef __IPMMU_VMSA_H__
> +#define __IPMMU_VMSA_H__
> +
> +struct ipmmu_vmsa_master {
> +	const char *name;
> +	unsigned int utlb;
> +};
> +
> +struct ipmmu_vmsa_platform_data {
> +	const struct ipmmu_vmsa_master *masters;
> +	unsigned int num_masters;
> +};
> +
> +#endif /* __IPMMU_VMSA_H__ */