WSL2-Linux-Kernel/drivers/iommu/mtk_iommu_v1.c

720 строки
19 KiB
C

/*
* Copyright (c) 2015-2016 MediaTek Inc.
* Author: Honghui Zhang <honghui.zhang@mediatek.com>
*
* Based on driver/iommu/mtk_iommu.c
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/bootmem.h>
#include <linux/bug.h>
#include <linux/clk.h>
#include <linux/component.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/dma-iommu.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iommu.h>
#include <linux/iopoll.h>
#include <linux/list.h>
#include <linux/of_address.h>
#include <linux/of_iommu.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <asm/barrier.h>
#include <asm/dma-iommu.h>
#include <linux/module.h>
#include <dt-bindings/memory/mt2701-larb-port.h>
#include <soc/mediatek/smi.h>
#include "mtk_iommu.h"
#define REG_MMU_PT_BASE_ADDR 0x000
#define F_ALL_INVLD 0x2
#define F_MMU_INV_RANGE 0x1
#define F_INVLD_EN0 BIT(0)
#define F_INVLD_EN1 BIT(1)
#define F_MMU_FAULT_VA_MSK 0xfffff000
#define MTK_PROTECT_PA_ALIGN 128
#define REG_MMU_CTRL_REG 0x210
#define F_MMU_CTRL_COHERENT_EN BIT(8)
#define REG_MMU_IVRP_PADDR 0x214
#define REG_MMU_INT_CONTROL 0x220
#define F_INT_TRANSLATION_FAULT BIT(0)
#define F_INT_MAIN_MULTI_HIT_FAULT BIT(1)
#define F_INT_INVALID_PA_FAULT BIT(2)
#define F_INT_ENTRY_REPLACEMENT_FAULT BIT(3)
#define F_INT_TABLE_WALK_FAULT BIT(4)
#define F_INT_TLB_MISS_FAULT BIT(5)
#define F_INT_PFH_DMA_FIFO_OVERFLOW BIT(6)
#define F_INT_MISS_DMA_FIFO_OVERFLOW BIT(7)
#define F_MMU_TF_PROTECT_SEL(prot) (((prot) & 0x3) << 5)
#define F_INT_CLR_BIT BIT(12)
#define REG_MMU_FAULT_ST 0x224
#define REG_MMU_FAULT_VA 0x228
#define REG_MMU_INVLD_PA 0x22C
#define REG_MMU_INT_ID 0x388
#define REG_MMU_INVALIDATE 0x5c0
#define REG_MMU_INVLD_START_A 0x5c4
#define REG_MMU_INVLD_END_A 0x5c8
#define REG_MMU_INV_SEL 0x5d8
#define REG_MMU_STANDARD_AXI_MODE 0x5e8
#define REG_MMU_DCM 0x5f0
#define F_MMU_DCM_ON BIT(1)
#define REG_MMU_CPE_DONE 0x60c
#define F_DESC_VALID 0x2
#define F_DESC_NONSEC BIT(3)
#define MT2701_M4U_TF_LARB(TF) (6 - (((TF) >> 13) & 0x7))
#define MT2701_M4U_TF_PORT(TF) (((TF) >> 8) & 0xF)
/* MTK generation one iommu HW only support 4K size mapping */
#define MT2701_IOMMU_PAGE_SHIFT 12
#define MT2701_IOMMU_PAGE_SIZE (1UL << MT2701_IOMMU_PAGE_SHIFT)
/*
* MTK m4u support 4GB iova address space, and only support 4K page
* mapping. So the pagetable size should be exactly as 4M.
*/
#define M2701_IOMMU_PGT_SIZE SZ_4M
struct mtk_iommu_domain {
spinlock_t pgtlock; /* lock for page table */
struct iommu_domain domain;
u32 *pgt_va;
dma_addr_t pgt_pa;
struct mtk_iommu_data *data;
};
static struct mtk_iommu_domain *to_mtk_domain(struct iommu_domain *dom)
{
return container_of(dom, struct mtk_iommu_domain, domain);
}
static const int mt2701_m4u_in_larb[] = {
LARB0_PORT_OFFSET, LARB1_PORT_OFFSET,
LARB2_PORT_OFFSET, LARB3_PORT_OFFSET
};
static inline int mt2701_m4u_to_larb(int id)
{
int i;
for (i = ARRAY_SIZE(mt2701_m4u_in_larb) - 1; i >= 0; i--)
if ((id) >= mt2701_m4u_in_larb[i])
return i;
return 0;
}
static inline int mt2701_m4u_to_port(int id)
{
int larb = mt2701_m4u_to_larb(id);
return id - mt2701_m4u_in_larb[larb];
}
static void mtk_iommu_tlb_flush_all(struct mtk_iommu_data *data)
{
writel_relaxed(F_INVLD_EN1 | F_INVLD_EN0,
data->base + REG_MMU_INV_SEL);
writel_relaxed(F_ALL_INVLD, data->base + REG_MMU_INVALIDATE);
wmb(); /* Make sure the tlb flush all done */
}
static void mtk_iommu_tlb_flush_range(struct mtk_iommu_data *data,
unsigned long iova, size_t size)
{
int ret;
u32 tmp;
writel_relaxed(F_INVLD_EN1 | F_INVLD_EN0,
data->base + REG_MMU_INV_SEL);
writel_relaxed(iova & F_MMU_FAULT_VA_MSK,
data->base + REG_MMU_INVLD_START_A);
writel_relaxed((iova + size - 1) & F_MMU_FAULT_VA_MSK,
data->base + REG_MMU_INVLD_END_A);
writel_relaxed(F_MMU_INV_RANGE, data->base + REG_MMU_INVALIDATE);
ret = readl_poll_timeout_atomic(data->base + REG_MMU_CPE_DONE,
tmp, tmp != 0, 10, 100000);
if (ret) {
dev_warn(data->dev,
"Partial TLB flush timed out, falling back to full flush\n");
mtk_iommu_tlb_flush_all(data);
}
/* Clear the CPE status */
writel_relaxed(0, data->base + REG_MMU_CPE_DONE);
}
static irqreturn_t mtk_iommu_isr(int irq, void *dev_id)
{
struct mtk_iommu_data *data = dev_id;
struct mtk_iommu_domain *dom = data->m4u_dom;
u32 int_state, regval, fault_iova, fault_pa;
unsigned int fault_larb, fault_port;
/* Read error information from registers */
int_state = readl_relaxed(data->base + REG_MMU_FAULT_ST);
fault_iova = readl_relaxed(data->base + REG_MMU_FAULT_VA);
fault_iova &= F_MMU_FAULT_VA_MSK;
fault_pa = readl_relaxed(data->base + REG_MMU_INVLD_PA);
regval = readl_relaxed(data->base + REG_MMU_INT_ID);
fault_larb = MT2701_M4U_TF_LARB(regval);
fault_port = MT2701_M4U_TF_PORT(regval);
/*
* MTK v1 iommu HW could not determine whether the fault is read or
* write fault, report as read fault.
*/
if (report_iommu_fault(&dom->domain, data->dev, fault_iova,
IOMMU_FAULT_READ))
dev_err_ratelimited(data->dev,
"fault type=0x%x iova=0x%x pa=0x%x larb=%d port=%d\n",
int_state, fault_iova, fault_pa,
fault_larb, fault_port);
/* Interrupt clear */
regval = readl_relaxed(data->base + REG_MMU_INT_CONTROL);
regval |= F_INT_CLR_BIT;
writel_relaxed(regval, data->base + REG_MMU_INT_CONTROL);
mtk_iommu_tlb_flush_all(data);
return IRQ_HANDLED;
}
static void mtk_iommu_config(struct mtk_iommu_data *data,
struct device *dev, bool enable)
{
struct mtk_smi_larb_iommu *larb_mmu;
unsigned int larbid, portid;
struct iommu_fwspec *fwspec = dev->iommu_fwspec;
int i;
for (i = 0; i < fwspec->num_ids; ++i) {
larbid = mt2701_m4u_to_larb(fwspec->ids[i]);
portid = mt2701_m4u_to_port(fwspec->ids[i]);
larb_mmu = &data->smi_imu.larb_imu[larbid];
dev_dbg(dev, "%s iommu port: %d\n",
enable ? "enable" : "disable", portid);
if (enable)
larb_mmu->mmu |= MTK_SMI_MMU_EN(portid);
else
larb_mmu->mmu &= ~MTK_SMI_MMU_EN(portid);
}
}
static int mtk_iommu_domain_finalise(struct mtk_iommu_data *data)
{
struct mtk_iommu_domain *dom = data->m4u_dom;
spin_lock_init(&dom->pgtlock);
dom->pgt_va = dma_zalloc_coherent(data->dev,
M2701_IOMMU_PGT_SIZE,
&dom->pgt_pa, GFP_KERNEL);
if (!dom->pgt_va)
return -ENOMEM;
writel(dom->pgt_pa, data->base + REG_MMU_PT_BASE_ADDR);
dom->data = data;
return 0;
}
static struct iommu_domain *mtk_iommu_domain_alloc(unsigned type)
{
struct mtk_iommu_domain *dom;
if (type != IOMMU_DOMAIN_UNMANAGED)
return NULL;
dom = kzalloc(sizeof(*dom), GFP_KERNEL);
if (!dom)
return NULL;
return &dom->domain;
}
static void mtk_iommu_domain_free(struct iommu_domain *domain)
{
struct mtk_iommu_domain *dom = to_mtk_domain(domain);
struct mtk_iommu_data *data = dom->data;
dma_free_coherent(data->dev, M2701_IOMMU_PGT_SIZE,
dom->pgt_va, dom->pgt_pa);
kfree(to_mtk_domain(domain));
}
static int mtk_iommu_attach_device(struct iommu_domain *domain,
struct device *dev)
{
struct mtk_iommu_domain *dom = to_mtk_domain(domain);
struct mtk_iommu_data *data = dev->iommu_fwspec->iommu_priv;
int ret;
if (!data)
return -ENODEV;
if (!data->m4u_dom) {
data->m4u_dom = dom;
ret = mtk_iommu_domain_finalise(data);
if (ret) {
data->m4u_dom = NULL;
return ret;
}
}
mtk_iommu_config(data, dev, true);
return 0;
}
static void mtk_iommu_detach_device(struct iommu_domain *domain,
struct device *dev)
{
struct mtk_iommu_data *data = dev->iommu_fwspec->iommu_priv;
if (!data)
return;
mtk_iommu_config(data, dev, false);
}
static int mtk_iommu_map(struct iommu_domain *domain, unsigned long iova,
phys_addr_t paddr, size_t size, int prot)
{
struct mtk_iommu_domain *dom = to_mtk_domain(domain);
unsigned int page_num = size >> MT2701_IOMMU_PAGE_SHIFT;
unsigned long flags;
unsigned int i;
u32 *pgt_base_iova = dom->pgt_va + (iova >> MT2701_IOMMU_PAGE_SHIFT);
u32 pabase = (u32)paddr;
int map_size = 0;
spin_lock_irqsave(&dom->pgtlock, flags);
for (i = 0; i < page_num; i++) {
if (pgt_base_iova[i]) {
memset(pgt_base_iova, 0, i * sizeof(u32));
break;
}
pgt_base_iova[i] = pabase | F_DESC_VALID | F_DESC_NONSEC;
pabase += MT2701_IOMMU_PAGE_SIZE;
map_size += MT2701_IOMMU_PAGE_SIZE;
}
spin_unlock_irqrestore(&dom->pgtlock, flags);
mtk_iommu_tlb_flush_range(dom->data, iova, size);
return map_size == size ? 0 : -EEXIST;
}
static size_t mtk_iommu_unmap(struct iommu_domain *domain,
unsigned long iova, size_t size)
{
struct mtk_iommu_domain *dom = to_mtk_domain(domain);
unsigned long flags;
u32 *pgt_base_iova = dom->pgt_va + (iova >> MT2701_IOMMU_PAGE_SHIFT);
unsigned int page_num = size >> MT2701_IOMMU_PAGE_SHIFT;
spin_lock_irqsave(&dom->pgtlock, flags);
memset(pgt_base_iova, 0, page_num * sizeof(u32));
spin_unlock_irqrestore(&dom->pgtlock, flags);
mtk_iommu_tlb_flush_range(dom->data, iova, size);
return size;
}
static phys_addr_t mtk_iommu_iova_to_phys(struct iommu_domain *domain,
dma_addr_t iova)
{
struct mtk_iommu_domain *dom = to_mtk_domain(domain);
unsigned long flags;
phys_addr_t pa;
spin_lock_irqsave(&dom->pgtlock, flags);
pa = *(dom->pgt_va + (iova >> MT2701_IOMMU_PAGE_SHIFT));
pa = pa & (~(MT2701_IOMMU_PAGE_SIZE - 1));
spin_unlock_irqrestore(&dom->pgtlock, flags);
return pa;
}
static struct iommu_ops mtk_iommu_ops;
/*
* MTK generation one iommu HW only support one iommu domain, and all the client
* sharing the same iova address space.
*/
static int mtk_iommu_create_mapping(struct device *dev,
struct of_phandle_args *args)
{
struct mtk_iommu_data *data;
struct platform_device *m4updev;
struct dma_iommu_mapping *mtk_mapping;
struct device *m4udev;
int ret;
if (args->args_count != 1) {
dev_err(dev, "invalid #iommu-cells(%d) property for IOMMU\n",
args->args_count);
return -EINVAL;
}
if (!dev->iommu_fwspec) {
ret = iommu_fwspec_init(dev, &args->np->fwnode, &mtk_iommu_ops);
if (ret)
return ret;
} else if (dev->iommu_fwspec->ops != &mtk_iommu_ops) {
return -EINVAL;
}
if (!dev->iommu_fwspec->iommu_priv) {
/* Get the m4u device */
m4updev = of_find_device_by_node(args->np);
if (WARN_ON(!m4updev))
return -EINVAL;
dev->iommu_fwspec->iommu_priv = platform_get_drvdata(m4updev);
}
ret = iommu_fwspec_add_ids(dev, args->args, 1);
if (ret)
return ret;
data = dev->iommu_fwspec->iommu_priv;
m4udev = data->dev;
mtk_mapping = m4udev->archdata.iommu;
if (!mtk_mapping) {
/* MTK iommu support 4GB iova address space. */
mtk_mapping = arm_iommu_create_mapping(&platform_bus_type,
0, 1ULL << 32);
if (IS_ERR(mtk_mapping))
return PTR_ERR(mtk_mapping);
m4udev->archdata.iommu = mtk_mapping;
}
return 0;
}
static int mtk_iommu_add_device(struct device *dev)
{
struct dma_iommu_mapping *mtk_mapping;
struct of_phandle_args iommu_spec;
struct of_phandle_iterator it;
struct mtk_iommu_data *data;
struct iommu_group *group;
int err;
of_for_each_phandle(&it, err, dev->of_node, "iommus",
"#iommu-cells", 0) {
int count = of_phandle_iterator_args(&it, iommu_spec.args,
MAX_PHANDLE_ARGS);
iommu_spec.np = of_node_get(it.node);
iommu_spec.args_count = count;
mtk_iommu_create_mapping(dev, &iommu_spec);
of_node_put(iommu_spec.np);
}
if (!dev->iommu_fwspec || dev->iommu_fwspec->ops != &mtk_iommu_ops)
return -ENODEV; /* Not a iommu client device */
/*
* This is a short-term bodge because the ARM DMA code doesn't
* understand multi-device groups, but we have to call into it
* successfully (and not just rely on a normal IOMMU API attach
* here) in order to set the correct DMA API ops on @dev.
*/
group = iommu_group_alloc();
if (IS_ERR(group))
return PTR_ERR(group);
err = iommu_group_add_device(group, dev);
iommu_group_put(group);
if (err)
return err;
data = dev->iommu_fwspec->iommu_priv;
mtk_mapping = data->dev->archdata.iommu;
err = arm_iommu_attach_device(dev, mtk_mapping);
if (err) {
iommu_group_remove_device(dev);
return err;
}
return iommu_device_link(&data->iommu, dev);;
}
static void mtk_iommu_remove_device(struct device *dev)
{
struct mtk_iommu_data *data;
if (!dev->iommu_fwspec || dev->iommu_fwspec->ops != &mtk_iommu_ops)
return;
data = dev->iommu_fwspec->iommu_priv;
iommu_device_unlink(&data->iommu, dev);
iommu_group_remove_device(dev);
iommu_fwspec_free(dev);
}
static int mtk_iommu_hw_init(const struct mtk_iommu_data *data)
{
u32 regval;
int ret;
ret = clk_prepare_enable(data->bclk);
if (ret) {
dev_err(data->dev, "Failed to enable iommu bclk(%d)\n", ret);
return ret;
}
regval = F_MMU_CTRL_COHERENT_EN | F_MMU_TF_PROTECT_SEL(2);
writel_relaxed(regval, data->base + REG_MMU_CTRL_REG);
regval = F_INT_TRANSLATION_FAULT |
F_INT_MAIN_MULTI_HIT_FAULT |
F_INT_INVALID_PA_FAULT |
F_INT_ENTRY_REPLACEMENT_FAULT |
F_INT_TABLE_WALK_FAULT |
F_INT_TLB_MISS_FAULT |
F_INT_PFH_DMA_FIFO_OVERFLOW |
F_INT_MISS_DMA_FIFO_OVERFLOW;
writel_relaxed(regval, data->base + REG_MMU_INT_CONTROL);
/* protect memory,hw will write here while translation fault */
writel_relaxed(data->protect_base,
data->base + REG_MMU_IVRP_PADDR);
writel_relaxed(F_MMU_DCM_ON, data->base + REG_MMU_DCM);
if (devm_request_irq(data->dev, data->irq, mtk_iommu_isr, 0,
dev_name(data->dev), (void *)data)) {
writel_relaxed(0, data->base + REG_MMU_PT_BASE_ADDR);
clk_disable_unprepare(data->bclk);
dev_err(data->dev, "Failed @ IRQ-%d Request\n", data->irq);
return -ENODEV;
}
return 0;
}
static struct iommu_ops mtk_iommu_ops = {
.domain_alloc = mtk_iommu_domain_alloc,
.domain_free = mtk_iommu_domain_free,
.attach_dev = mtk_iommu_attach_device,
.detach_dev = mtk_iommu_detach_device,
.map = mtk_iommu_map,
.unmap = mtk_iommu_unmap,
.map_sg = default_iommu_map_sg,
.iova_to_phys = mtk_iommu_iova_to_phys,
.add_device = mtk_iommu_add_device,
.remove_device = mtk_iommu_remove_device,
.pgsize_bitmap = ~0UL << MT2701_IOMMU_PAGE_SHIFT,
};
static const struct of_device_id mtk_iommu_of_ids[] = {
{ .compatible = "mediatek,mt2701-m4u", },
{}
};
static const struct component_master_ops mtk_iommu_com_ops = {
.bind = mtk_iommu_bind,
.unbind = mtk_iommu_unbind,
};
static int mtk_iommu_probe(struct platform_device *pdev)
{
struct mtk_iommu_data *data;
struct device *dev = &pdev->dev;
struct resource *res;
struct component_match *match = NULL;
struct of_phandle_args larb_spec;
struct of_phandle_iterator it;
void *protect;
int larb_nr, ret, err;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->dev = dev;
/* Protect memory. HW will access here while translation fault.*/
protect = devm_kzalloc(dev, MTK_PROTECT_PA_ALIGN * 2,
GFP_KERNEL | GFP_DMA);
if (!protect)
return -ENOMEM;
data->protect_base = ALIGN(virt_to_phys(protect), MTK_PROTECT_PA_ALIGN);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
data->base = devm_ioremap_resource(dev, res);
if (IS_ERR(data->base))
return PTR_ERR(data->base);
data->irq = platform_get_irq(pdev, 0);
if (data->irq < 0)
return data->irq;
data->bclk = devm_clk_get(dev, "bclk");
if (IS_ERR(data->bclk))
return PTR_ERR(data->bclk);
larb_nr = 0;
of_for_each_phandle(&it, err, dev->of_node,
"mediatek,larbs", NULL, 0) {
struct platform_device *plarbdev;
int count = of_phandle_iterator_args(&it, larb_spec.args,
MAX_PHANDLE_ARGS);
if (count)
continue;
larb_spec.np = of_node_get(it.node);
if (!of_device_is_available(larb_spec.np))
continue;
plarbdev = of_find_device_by_node(larb_spec.np);
if (!plarbdev) {
plarbdev = of_platform_device_create(
larb_spec.np, NULL,
platform_bus_type.dev_root);
if (!plarbdev) {
of_node_put(larb_spec.np);
return -EPROBE_DEFER;
}
}
data->smi_imu.larb_imu[larb_nr].dev = &plarbdev->dev;
component_match_add_release(dev, &match, release_of,
compare_of, larb_spec.np);
larb_nr++;
}
data->smi_imu.larb_nr = larb_nr;
platform_set_drvdata(pdev, data);
ret = mtk_iommu_hw_init(data);
if (ret)
return ret;
ret = iommu_device_sysfs_add(&data->iommu, &pdev->dev, NULL,
dev_name(&pdev->dev));
if (ret)
return ret;
iommu_device_set_ops(&data->iommu, &mtk_iommu_ops);
ret = iommu_device_register(&data->iommu);
if (ret)
return ret;
if (!iommu_present(&platform_bus_type))
bus_set_iommu(&platform_bus_type, &mtk_iommu_ops);
return component_master_add_with_match(dev, &mtk_iommu_com_ops, match);
}
static int mtk_iommu_remove(struct platform_device *pdev)
{
struct mtk_iommu_data *data = platform_get_drvdata(pdev);
iommu_device_sysfs_remove(&data->iommu);
iommu_device_unregister(&data->iommu);
if (iommu_present(&platform_bus_type))
bus_set_iommu(&platform_bus_type, NULL);
clk_disable_unprepare(data->bclk);
devm_free_irq(&pdev->dev, data->irq, data);
component_master_del(&pdev->dev, &mtk_iommu_com_ops);
return 0;
}
static int __maybe_unused mtk_iommu_suspend(struct device *dev)
{
struct mtk_iommu_data *data = dev_get_drvdata(dev);
struct mtk_iommu_suspend_reg *reg = &data->reg;
void __iomem *base = data->base;
reg->standard_axi_mode = readl_relaxed(base +
REG_MMU_STANDARD_AXI_MODE);
reg->dcm_dis = readl_relaxed(base + REG_MMU_DCM);
reg->ctrl_reg = readl_relaxed(base + REG_MMU_CTRL_REG);
reg->int_control0 = readl_relaxed(base + REG_MMU_INT_CONTROL);
return 0;
}
static int __maybe_unused mtk_iommu_resume(struct device *dev)
{
struct mtk_iommu_data *data = dev_get_drvdata(dev);
struct mtk_iommu_suspend_reg *reg = &data->reg;
void __iomem *base = data->base;
writel_relaxed(data->m4u_dom->pgt_pa, base + REG_MMU_PT_BASE_ADDR);
writel_relaxed(reg->standard_axi_mode,
base + REG_MMU_STANDARD_AXI_MODE);
writel_relaxed(reg->dcm_dis, base + REG_MMU_DCM);
writel_relaxed(reg->ctrl_reg, base + REG_MMU_CTRL_REG);
writel_relaxed(reg->int_control0, base + REG_MMU_INT_CONTROL);
writel_relaxed(data->protect_base, base + REG_MMU_IVRP_PADDR);
return 0;
}
static const struct dev_pm_ops mtk_iommu_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(mtk_iommu_suspend, mtk_iommu_resume)
};
static struct platform_driver mtk_iommu_driver = {
.probe = mtk_iommu_probe,
.remove = mtk_iommu_remove,
.driver = {
.name = "mtk-iommu-v1",
.of_match_table = mtk_iommu_of_ids,
.pm = &mtk_iommu_pm_ops,
}
};
static int __init m4u_init(void)
{
return platform_driver_register(&mtk_iommu_driver);
}
static void __exit m4u_exit(void)
{
return platform_driver_unregister(&mtk_iommu_driver);
}
subsys_initcall(m4u_init);
module_exit(m4u_exit);
MODULE_DESCRIPTION("IOMMU API for MTK architected m4u v1 implementations");
MODULE_AUTHOR("Honghui Zhang <honghui.zhang@mediatek.com>");
MODULE_LICENSE("GPL v2");