SMMU的使用

-bash-4.2$ cat drivers/smmu_test/smmu_test.c
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/timer.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/debugfs.h>
#include <linux/miscdevice.h>
#include <linux/dma-mapping.h>
#include <linux/of_device.h>
#include <linux/slab.h>
#include <asm/current.h>
#include <linux/sched.h>
#include <linux/err.h>
#include <linux/kthread.h>
#include <linux/iommu.h>


/*
CONFIG_OF_IOMMU
CONFIG_IOMMU_DMA
CONFIG_DMA_API_DEBUG
CONFIG_IOMMU_IO_PGTABLE_LPAE_SELFTEST
*/

/*
test {
        compatible = "test_id";
        dma-coherent;
        dma-ranges = <0x0 0x0 0x0 0x0 0x80000000 0x00000000>;
        iommus = <&smmu0 0>;


        status = "okay";
};
*/



//#define RESV_PHY_ADDR 0xe0000000
//#define RESV_PHY_SIZE 0x80000000
#define RESV_PHY_ADDR 0x2100000000
#define RESV_PHY_SIZE 0x80000000

unsigned long my_iova = 0x50100000;

static int test_probe(struct platform_device *dev)
{
        int ret;
        phys_addr_t phys_addr;
        size_t size;
        struct iommu_domain *mydomain;

        phys_addr = RESV_PHY_ADDR;
        size = RESV_PHY_SIZE;

        pr_info("dbg_added, probe:%s:%d\n", __FUNCTION__, __LINE__);


        mydomain = iommu_domain_alloc(&platform_bus_type);
        if (mydomain == NULL) {
                pr_info("dbg_added iommu_domain_alloc error\n");
                return -1;
        } else {
                pr_info("dbg_added iommu_domain_alloc ok\n");
        }

        ret = iommu_attach_device(mydomain, &dev->dev);
        if (ret) {
                        pr_info("dbg_added iommu_attach_device error\n");
                        return -1;
        } else {
                pr_info("dbg_added iommu_attach_device ok\n");
        }

        ret = iommu_map(mydomain, my_iova, phys_addr, size, IOMMU_READ | IOMMU_WRITE);
    if (ret < 0) {
                pr_info("dbg_added iommu_map error\n");
                return -1;
        } else {
                pr_info("dbg_added iommu_map ok\n");
        }

        return 0;
}

static int test_remove(struct platform_device *dev)
{
        return 0;
}

static const struct of_device_id test_of_match[] = {
        { .compatible = "test_id" },
        {}
};

MODULE_DEVICE_TABLE(of, test_of_match);

static struct platform_driver test_platform_driver = {
        .driver = {
                .name = "smmu-test",
                .of_match_table = test_of_match,
        },
        .probe = test_probe,
        .remove = test_remove,
};


static int __init test_init(void)
{
        pr_info("dbg_added init module\n");
        pr_info("dbg_added the process is %s pid %i\n", current->comm, current->pid);

        platform_driver_register(&test_platform_driver);

        return 0;
}
static void __exit test_exit(void)
{
        platform_driver_unregister(&test_platform_driver);
        pr_info("dbg_added exit modules\n");
}

MODULE_AUTHOR("cl");
MODULE_LICENSE("Dual BSD/GPL");

module_init(test_init);
module_exit(test_exit);-bash-4.2$