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From:   Chunyan Zhang <zhang.lyra@gmail.com>
To:     Robin Murphy <robin.murphy@arm.com>,
        Rob Herring <robh+dt@kernel.org>,
        Joerg Roedel <joro@8bytes.org>
Cc:     iommu@lists.linux-foundation.org, devicetree@vger.kernel.org,
        Baolin Wang <baolin.wang7@gmail.com>,
        linux-kernel@vger.kernel.org, Orson Zhai <orsonzhai@gmail.com>,
        Chunyan Zhang <zhang.lyra@gmail.com>,
        Sheng Xu <sheng.xu@unisoc.com>,
        Chunyan Zhang <chunyan.zhang@unisoc.com>
Subject: [PATCH v3 2/2] iommu: add Unisoc iommu basic driver
Date:   Wed,  3 Feb 2021 17:07:27 +0800
Message-Id: <20210203090727.789939-3-zhang.lyra@gmail.com>
In-Reply-To: <20210203090727.789939-1-zhang.lyra@gmail.com>
References: <20210203090727.789939-1-zhang.lyra@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Chunyan Zhang <chunyan.zhang@unisoc.com>

This iommu module can be used by Unisoc's multimedia devices, such as
display, Image codec(jpeg) and a few signal processors, including
VSP(video), GSP(graphic), ISP(image), and CPP(camera pixel processor), etc.

Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
---
 drivers/iommu/Kconfig      |  12 +
 drivers/iommu/Makefile     |   1 +
 drivers/iommu/sprd-iommu.c | 600 +++++++++++++++++++++++++++++++++++++
 3 files changed, 613 insertions(+)
 create mode 100644 drivers/iommu/sprd-iommu.c

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 192ef8f61310..99e7712f3903 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -408,4 +408,16 @@ config VIRTIO_IOMMU
 
 	  Say Y here if you intend to run this kernel as a guest.
 
+config SPRD_IOMMU
+	tristate "Unisoc IOMMU Support"
+	depends on ARCH_SPRD || COMPILE_TEST
+	select IOMMU_API
+	help
+	  Support for IOMMU on Unisoc's SoCs, this iommu can be used by
+	  Unisoc's multimedia devices, such as display, Image codec(jpeg)
+	  and a few signal processors, including VSP(video), GSP(graphic),
+	  ISP(image), and CPP(camera pixel processor), etc.
+
+	  Say Y here if you want to use the multimedia devices listed above.
+
 endif # IOMMU_SUPPORT
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index 61bd30cd8369..5925b6af2123 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile
@@ -28,3 +28,4 @@ obj-$(CONFIG_S390_IOMMU) += s390-iommu.o
 obj-$(CONFIG_HYPERV_IOMMU) += hyperv-iommu.o
 obj-$(CONFIG_VIRTIO_IOMMU) += virtio-iommu.o
 obj-$(CONFIG_IOMMU_SVA_LIB) += iommu-sva-lib.o
+obj-$(CONFIG_SPRD_IOMMU) += sprd-iommu.o
diff --git a/drivers/iommu/sprd-iommu.c b/drivers/iommu/sprd-iommu.c
new file mode 100644
index 000000000000..6b3c36785c7c
--- /dev/null
+++ b/drivers/iommu/sprd-iommu.c
@@ -0,0 +1,600 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Unisoc IOMMU driver
+ *
+ * Copyright (C) 2020 Unisoc, Inc.
+ * Author: Chunyan Zhang <chunyan.zhang@unisoc.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/dma-iommu.h>
+#include <linux/dma-mapping.h>
+#include <linux/errno.h>
+#include <linux/iommu.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#define SPRD_IOMMU_PAGE_SHIFT	12
+#define SPRD_IOMMU_PAGE_SIZE	SZ_4K
+
+#define SPRD_EX_CFG		0x0
+#define SPRD_IOMMU_VAOR_BYPASS	BIT(4)
+#define SPRD_IOMMU_GATE_EN	BIT(1)
+#define SPRD_IOMMU_EN		BIT(0)
+#define SPRD_EX_UPDATE		0x4
+#define SPRD_EX_FIRST_VPN	0x8
+#define SPRD_EX_VPN_RANGE	0xc
+#define SPRD_EX_FIRST_PPN	0x10
+#define SPRD_EX_DEFAULT_PPN	0x14
+
+#define SPRD_IOMMU_VERSION	0x0
+#define SPRD_VERSION_MASK	GENMASK(15, 8)
+#define SPRD_VERSION_SHIFT	0x8
+#define SPRD_VAU_CFG		0x4
+#define SPRD_VAU_UPDATE		0x8
+#define SPRD_VAU_AUTH_CFG	0xc
+#define SPRD_VAU_FIRST_PPN	0x10
+#define SPRD_VAU_DEFAULT_PPN_RD	0x14
+#define SPRD_VAU_DEFAULT_PPN_WR	0x18
+#define SPRD_VAU_FIRST_VPN	0x1c
+#define SPRD_VAU_VPN_RANGE	0x20
+
+enum sprd_iommu_version {
+	SPRD_IOMMU_EX,
+	SPRD_IOMMU_VAU,
+};
+
+/*
+ * struct sprd_iommu_device - high-level sprd iommu device representation,
+ * including hardware information and configuration, also driver data, etc
+ *
+ * @ver: sprd iommu device version
+ * @prot_page_va: protect page base virtual address
+ * @prot_page_pa: protect page base physical address, data would be
+ *		  written to here while translation fault
+ * @base: mapped base address for accessing registers
+ * @reg_offset: some IOMMU shares the same range of registers with the multimedia
+ *		device which use it, this represents the iommu register offset
+ * @dev: pointer to basic device structure
+ * @iommu: IOMMU core representation
+ * @group: IOMMU group
+ * @eb: gate clock which controls iommu access
+ */
+struct sprd_iommu_device {
+	enum sprd_iommu_version	ver;
+	u32			*prot_page_va;
+	dma_addr_t		prot_page_pa;
+	struct regmap		*base;
+	unsigned int		reg_offset;
+	struct device		*dev;
+	struct iommu_device	iommu;
+	struct iommu_group	*group;
+	struct clk		*eb;
+};
+
+struct sprd_iommu_domain {
+	spinlock_t		pgtlock; /* lock for page table */
+	struct iommu_domain	domain;
+	u32			*pgt_va; /* page table virtual address base */
+	dma_addr_t		pgt_pa; /* page table physical address base */
+	struct sprd_iommu_device	*sdev;
+};
+
+static const struct iommu_ops sprd_iommu_ops;
+
+static struct sprd_iommu_domain *to_sprd_domain(struct iommu_domain *dom)
+{
+	return container_of(dom, struct sprd_iommu_domain, domain);
+}
+
+static inline void
+sprd_iommu_write(struct sprd_iommu_device *sdev, unsigned int reg, u32 val)
+{
+	regmap_write(sdev->base, sdev->reg_offset + reg, val);
+}
+
+static inline u32
+sprd_iommu_read(struct sprd_iommu_device *sdev, unsigned int reg)
+{
+	u32 val;
+
+	regmap_read(sdev->base, sdev->reg_offset + reg, &val);
+	return val;
+}
+
+static inline void
+sprd_iommu_update_bits(struct sprd_iommu_device *sdev, unsigned int reg,
+		  u32 mask, u32 shift, u32 val)
+{
+	u32 t = sprd_iommu_read(sdev, reg);
+
+	t = (t & (~(mask << shift))) | ((val & mask) << shift);
+	sprd_iommu_write(sdev, reg, t);
+}
+
+static inline int
+sprd_iommu_get_version(struct sprd_iommu_device *sdev)
+{
+	int ver = (sprd_iommu_read(sdev, SPRD_IOMMU_VERSION) &
+		   SPRD_VERSION_MASK) >> SPRD_VERSION_SHIFT;
+
+	switch (ver) {
+	case SPRD_IOMMU_EX:
+	case SPRD_IOMMU_VAU:
+		return ver;
+	default:
+		return -EINVAL;
+	}
+}
+
+static size_t
+sprd_iommu_pgt_size(struct iommu_domain *domain)
+{
+	return ((domain->geometry.aperture_end -
+		 domain->geometry.aperture_start + 1) >>
+		SPRD_IOMMU_PAGE_SHIFT) * sizeof(u32);
+}
+
+static struct iommu_domain *sprd_iommu_domain_alloc(unsigned int domain_type)
+{
+	struct sprd_iommu_domain *dom;
+
+	if (domain_type != IOMMU_DOMAIN_DMA && domain_type != IOMMU_DOMAIN_UNMANAGED)
+		return NULL;
+
+	dom = kzalloc(sizeof(*dom), GFP_KERNEL);
+	if (!dom)
+		return NULL;
+
+	if (iommu_get_dma_cookie(&dom->domain)) {
+		kfree(dom);
+		return NULL;
+	}
+
+	spin_lock_init(&dom->pgtlock);
+
+	dom->domain.geometry.aperture_start = 0;
+	dom->domain.geometry.aperture_end = SZ_256M - 1;
+
+	return &dom->domain;
+}
+
+static void sprd_iommu_domain_free(struct iommu_domain *domain)
+{
+	struct sprd_iommu_domain *dom = to_sprd_domain(domain);
+
+	iommu_put_dma_cookie(domain);
+	kfree(dom);
+}
+
+static void sprd_iommu_first_vpn(struct sprd_iommu_domain *dom)
+{
+	struct sprd_iommu_device *sdev = dom->sdev;
+	u32 val;
+	unsigned int reg;
+
+	if (sdev->ver == SPRD_IOMMU_EX)
+		reg = SPRD_EX_FIRST_VPN;
+	else
+		reg = SPRD_VAU_FIRST_VPN;
+
+	val = dom->domain.geometry.aperture_start >> SPRD_IOMMU_PAGE_SHIFT;
+	sprd_iommu_write(sdev, reg, val);
+}
+
+static void sprd_iommu_vpn_range(struct sprd_iommu_domain *dom)
+{
+	struct sprd_iommu_device *sdev = dom->sdev;
+	u32 val;
+	unsigned int reg;
+
+	if (sdev->ver == SPRD_IOMMU_EX)
+		reg = SPRD_EX_VPN_RANGE;
+	else
+		reg = SPRD_VAU_VPN_RANGE;
+
+	val = (dom->domain.geometry.aperture_end -
+	       dom->domain.geometry.aperture_start) >> SPRD_IOMMU_PAGE_SHIFT;
+	sprd_iommu_write(sdev, reg, val);
+}
+
+static void sprd_iommu_first_ppn(struct sprd_iommu_domain *dom)
+{
+	u32 val = dom->pgt_pa >> SPRD_IOMMU_PAGE_SHIFT;
+	struct sprd_iommu_device *sdev = dom->sdev;
+	unsigned int reg;
+
+	if (sdev->ver == SPRD_IOMMU_EX)
+		reg = SPRD_EX_FIRST_PPN;
+	else
+		reg = SPRD_VAU_FIRST_PPN;
+
+	sprd_iommu_write(sdev, reg, val);
+}
+
+static void sprd_iommu_default_ppn(struct sprd_iommu_device *sdev)
+{
+	u32 val = sdev->prot_page_pa >> SPRD_IOMMU_PAGE_SHIFT;
+
+	if (sdev->ver == SPRD_IOMMU_EX) {
+		sprd_iommu_write(sdev, SPRD_EX_DEFAULT_PPN, val);
+	} else if (sdev->ver == SPRD_IOMMU_VAU) {
+		sprd_iommu_write(sdev, SPRD_VAU_DEFAULT_PPN_RD, val);
+		sprd_iommu_write(sdev, SPRD_VAU_DEFAULT_PPN_WR, val);
+	}
+}
+
+static void sprd_iommu_hw_en(struct sprd_iommu_device *sdev, bool en)
+{
+	unsigned int reg_cfg;
+	u32 mask, val;
+
+	if (sdev->ver == SPRD_IOMMU_EX)
+		reg_cfg = SPRD_EX_CFG;
+	else
+		reg_cfg = SPRD_VAU_CFG;
+
+	mask = SPRD_IOMMU_EN | SPRD_IOMMU_GATE_EN;
+	val = en ? mask : 0;
+	sprd_iommu_update_bits(sdev, reg_cfg, mask, 0, val);
+}
+
+static int sprd_iommu_attach_device(struct iommu_domain *domain,
+				    struct device *dev)
+{
+	struct sprd_iommu_device *sdev = dev_iommu_priv_get(dev);
+	struct sprd_iommu_domain *dom = to_sprd_domain(domain);
+	size_t pgt_size = sprd_iommu_pgt_size(domain);
+
+	if (dom->sdev) {
+		pr_err("There's already a device attached to this domain.\n");
+		return -EINVAL;
+	}
+
+	dom->pgt_va = dma_alloc_coherent(sdev->dev, pgt_size, &dom->pgt_pa, GFP_KERNEL);
+	if (!dom->pgt_va)
+		return -ENOMEM;
+
+	dom->sdev = sdev;
+
+	sprd_iommu_first_ppn(dom);
+	sprd_iommu_first_vpn(dom);
+	sprd_iommu_vpn_range(dom);
+	sprd_iommu_default_ppn(sdev);
+	sprd_iommu_hw_en(sdev, true);
+
+	return 0;
+}
+
+static void sprd_iommu_detach_device(struct iommu_domain *domain,
+					     struct device *dev)
+{
+	struct sprd_iommu_domain *dom = to_sprd_domain(domain);
+	struct sprd_iommu_device *sdev = dom->sdev;
+	size_t pgt_size = sprd_iommu_pgt_size(domain);
+
+	if (!sdev)
+		return;
+
+	dma_free_coherent(sdev->dev, pgt_size, dom->pgt_va, dom->pgt_pa);
+	sprd_iommu_hw_en(sdev, false);
+	dom->sdev = NULL;
+}
+
+static int sprd_iommu_map(struct iommu_domain *domain, unsigned long iova,
+			  phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
+{
+	struct sprd_iommu_domain *dom = to_sprd_domain(domain);
+	unsigned int page_num = size >> SPRD_IOMMU_PAGE_SHIFT;
+	unsigned long flags;
+	unsigned int i;
+	u32 *pgt_base_iova;
+	u32 pabase = (u32)paddr;
+	unsigned long start = domain->geometry.aperture_start;
+	unsigned long end = domain->geometry.aperture_end;
+
+	if (!dom->sdev) {
+		pr_err("No sprd_iommu_device attached to the domain\n");
+		return -EINVAL;
+	}
+
+	if (iova < start || (iova + size) > (end + 1)) {
+		dev_err(dom->sdev->dev, "(iova(0x%lx) + sixe(%zx)) are not in the range!\n",
+			iova, size);
+		return -EINVAL;
+	}
+
+	pgt_base_iova = dom->pgt_va + ((iova - start) >> SPRD_IOMMU_PAGE_SHIFT);
+
+	spin_lock_irqsave(&dom->pgtlock, flags);
+	for (i = 0; i < page_num; i++) {
+		pgt_base_iova[i] = pabase >> SPRD_IOMMU_PAGE_SHIFT;
+		pabase += SPRD_IOMMU_PAGE_SIZE;
+	}
+	spin_unlock_irqrestore(&dom->pgtlock, flags);
+
+	return 0;
+}
+
+static size_t sprd_iommu_unmap(struct iommu_domain *domain, unsigned long iova,
+			size_t size, struct iommu_iotlb_gather *iotlb_gather)
+{
+	struct sprd_iommu_domain *dom = to_sprd_domain(domain);
+	unsigned long flags;
+	u32 *pgt_base_iova;
+	unsigned int page_num = size >> SPRD_IOMMU_PAGE_SHIFT;
+	unsigned long start = domain->geometry.aperture_start;
+	unsigned long end = domain->geometry.aperture_end;
+
+	if (iova < start || (iova + size) > (end + 1))
+		return -EINVAL;
+
+	pgt_base_iova = dom->pgt_va + ((iova - start) >> SPRD_IOMMU_PAGE_SHIFT);
+
+	spin_lock_irqsave(&dom->pgtlock, flags);
+	memset(pgt_base_iova, 0, page_num * sizeof(u32));
+	spin_unlock_irqrestore(&dom->pgtlock, flags);
+
+	return 0;
+}
+
+static void sprd_iommu_sync_map(struct iommu_domain *domain)
+{
+	struct sprd_iommu_domain *dom = to_sprd_domain(domain);
+	unsigned int reg;
+
+	if (dom->sdev->ver == SPRD_IOMMU_EX)
+		reg = SPRD_EX_UPDATE;
+	else
+		reg = SPRD_VAU_UPDATE;
+
+	/* clear iommu TLB buffer after page table updated */
+	sprd_iommu_write(dom->sdev, reg, 0xffffffff);
+}
+
+static void sprd_iommu_sync(struct iommu_domain *domain,
+				 struct iommu_iotlb_gather *iotlb_gather)
+{
+	sprd_iommu_sync_map(domain);
+}
+
+static phys_addr_t sprd_iommu_iova_to_phys(struct iommu_domain *domain,
+					   dma_addr_t iova)
+{
+	struct sprd_iommu_domain *dom = to_sprd_domain(domain);
+	unsigned long flags;
+	phys_addr_t pa;
+	unsigned long start = domain->geometry.aperture_start;
+	unsigned long end = domain->geometry.aperture_end;
+
+	if (WARN(iova < start || iova > end,
+		 "iova (0x%llx) exceeds the vpn range[0x%lx-0x%lx]\n",
+		 iova, start, end))
+		return 0;
+
+	spin_lock_irqsave(&dom->pgtlock, flags);
+	pa = *(dom->pgt_va + ((iova - start) >> SPRD_IOMMU_PAGE_SHIFT));
+	pa = (pa << SPRD_IOMMU_PAGE_SHIFT) + ((iova - start) & (SPRD_IOMMU_PAGE_SIZE - 1));
+	spin_unlock_irqrestore(&dom->pgtlock, flags);
+
+	return pa;
+}
+
+static struct iommu_device *sprd_iommu_probe_device(struct device *dev)
+{
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+	struct sprd_iommu_device *sdev;
+
+	if (!fwspec || fwspec->ops != &sprd_iommu_ops)
+		return ERR_PTR(-ENODEV);
+
+	sdev = dev_iommu_priv_get(dev);
+
+	return &sdev->iommu;
+}
+
+static void sprd_iommu_release_device(struct device *dev)
+{
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+
+	if (!fwspec || fwspec->ops != &sprd_iommu_ops)
+		return;
+
+	iommu_fwspec_free(dev);
+}
+
+static struct iommu_group *sprd_iommu_device_group(struct device *dev)
+{
+	struct sprd_iommu_device *sdev = dev_iommu_priv_get(dev);
+
+	return iommu_group_ref_get(sdev->group);
+}
+
+static int sprd_iommu_of_xlate(struct device *dev, struct of_phandle_args *args)
+{
+	struct platform_device *pdev;
+
+	if (!dev_iommu_priv_get(dev)) {
+		pdev = of_find_device_by_node(args->np);
+		dev_iommu_priv_set(dev, platform_get_drvdata(pdev));
+		platform_device_put(pdev);
+	}
+
+	return 0;
+}
+
+
+static const struct iommu_ops sprd_iommu_ops = {
+	.domain_alloc	= sprd_iommu_domain_alloc,
+	.domain_free	= sprd_iommu_domain_free,
+	.attach_dev	= sprd_iommu_attach_device,
+	.detach_dev	= sprd_iommu_detach_device,
+	.map		= sprd_iommu_map,
+	.unmap		= sprd_iommu_unmap,
+	.iotlb_sync_map	= sprd_iommu_sync_map,
+	.iotlb_sync	= sprd_iommu_sync,
+	.iova_to_phys	= sprd_iommu_iova_to_phys,
+	.probe_device	= sprd_iommu_probe_device,
+	.release_device	= sprd_iommu_release_device,
+	.device_group	= sprd_iommu_device_group,
+	.of_xlate	= sprd_iommu_of_xlate,
+	.pgsize_bitmap	= ~0UL << SPRD_IOMMU_PAGE_SHIFT,
+};
+
+static const struct of_device_id sprd_iommu_of_match[] = {
+	{ .compatible = "sprd,iommu-v1" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, sprd_iommu_of_match);
+
+/*
+ * Clock is not required, access to some of IOMMUs is controlled by gate
+ * clk, enabled clocks for that kind of IOMMUs before accessing.
+ * Return 0 for success or no clocks found.
+ */
+static int sprd_iommu_clk_enable(struct sprd_iommu_device *sdev)
+{
+	struct clk *eb;
+
+	eb = clk_get_optional(sdev->dev, 0);
+	if (!eb)
+		return 0;
+
+	if (IS_ERR(eb))
+		return PTR_ERR(eb);
+
+	sdev->eb = eb;
+	return clk_prepare_enable(eb);
+}
+
+static void sprd_iommu_clk_disable(struct sprd_iommu_device *sdev)
+{
+	if (sdev->eb)
+		clk_disable_unprepare(sdev->eb);
+}
+
+static struct regmap_config reg_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+};
+
+static int sprd_iommu_probe(struct platform_device *pdev)
+{
+	struct sprd_iommu_device *sdev;
+	struct device *dev = &pdev->dev;
+	void __iomem *base;
+	int ret;
+
+	sdev = devm_kzalloc(dev, sizeof(*sdev), GFP_KERNEL);
+	if (!sdev)
+		return -ENOMEM;
+
+	sdev->base = syscon_regmap_lookup_by_phandle_args(dev->of_node,
+				"sprd,iommu-regs", 1, &sdev->reg_offset);
+	if (IS_ERR(sdev->base)) {
+		sdev->reg_offset = 0;
+		base = devm_platform_ioremap_resource(pdev, 0);
+		if (IS_ERR(base)) {
+			dev_err(dev, "Failed to get ioremap resource.\n");
+			return PTR_ERR(base);
+		}
+
+		sdev->base = regmap_init_mmio(NULL, base, &reg_config);
+		if (IS_ERR(sdev->base)) {
+			dev_err(dev, "Failed to init regmap.\n");
+			return PTR_ERR(sdev->base);
+		}
+	}
+
+	sdev->prot_page_va = dma_alloc_coherent(dev, SPRD_IOMMU_PAGE_SIZE,
+						&sdev->prot_page_pa, GFP_KERNEL);
+	if (!sdev->prot_page_va)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, sdev);
+	sdev->dev = dev;
+
+	/* All the client devices are in the same iommu-group */
+	sdev->group = iommu_group_alloc();
+	if (IS_ERR(sdev->group)) {
+		ret = PTR_ERR(sdev->group);
+		goto free_page;
+	}
+
+	ret = iommu_device_sysfs_add(&sdev->iommu, dev, NULL, dev_name(dev));
+	if (ret)
+		goto put_group;
+
+	iommu_device_set_ops(&sdev->iommu, &sprd_iommu_ops);
+	iommu_device_set_fwnode(&sdev->iommu, &dev->of_node->fwnode);
+
+	ret = iommu_device_register(&sdev->iommu);
+	if (ret)
+		goto remove_sysfs;
+
+	if (!iommu_present(&platform_bus_type))
+		bus_set_iommu(&platform_bus_type, &sprd_iommu_ops);
+
+	ret = sprd_iommu_clk_enable(sdev);
+	if (ret)
+		goto unregister_iommu;
+
+	ret = sprd_iommu_get_version(sdev);
+	if (ret < 0) {
+		dev_err(dev, "iommu version(%d) is invalid.\n", ret);
+		goto disable_clk;
+	}
+	sdev->ver = ret;
+
+	return 0;
+
+disable_clk:
+	sprd_iommu_clk_disable(sdev);
+unregister_iommu:
+	iommu_device_unregister(&sdev->iommu);
+remove_sysfs:
+	iommu_device_sysfs_remove(&sdev->iommu);
+put_group:
+	iommu_group_put(sdev->group);
+free_page:
+	dma_free_coherent(sdev->dev, SPRD_IOMMU_PAGE_SIZE, sdev->prot_page_va, sdev->prot_page_pa);
+	return ret;
+}
+
+static int sprd_iommu_remove(struct platform_device *pdev)
+{
+	struct sprd_iommu_device *sdev = platform_get_drvdata(pdev);
+
+	dma_free_coherent(sdev->dev, SPRD_IOMMU_PAGE_SIZE, sdev->prot_page_va, sdev->prot_page_pa);
+
+	iommu_group_put(sdev->group);
+	sdev->group = NULL;
+
+	bus_set_iommu(&platform_bus_type, NULL);
+
+	platform_set_drvdata(pdev, NULL);
+	iommu_device_sysfs_remove(&sdev->iommu);
+	iommu_device_unregister(&sdev->iommu);
+
+	return 0;
+}
+
+static struct platform_driver sprd_iommu_driver = {
+	.driver	= {
+		.name		= "sprd-iommu",
+		.of_match_table	= sprd_iommu_of_match,
+		.suppress_bind_attrs = true,
+	},
+	.probe	= sprd_iommu_probe,
+	.remove	= sprd_iommu_remove,
+};
+module_platform_driver(sprd_iommu_driver);
+
+MODULE_DESCRIPTION("IOMMU driver for Unisoc SoCs");
+MODULE_ALIAS("platform:sprd-iommu");
+MODULE_LICENSE("GPL");
-- 
2.25.1