Re: [RFC PATCH] iommu: add ARM short descriptor page table allocator.

From: Matthias Brugger
Date: Tue May 12 2015 - 05:15:55 EST

2015-04-28 9:41 GMT+02:00 Yong Wu <yong.wu@xxxxxxxxxxxx>:
> This patch is for ARM Short Descriptor Format.It has 2-levels
> pagetable and the allocator supports 4K/64K/1M/16M.
>
> Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
> ---
> drivers/iommu/Kconfig | 7 +
> drivers/iommu/Makefile | 1 +
> drivers/iommu/io-pgtable-arm-short.c | 489 +++++++++++++++++++++++++++++++++++
> drivers/iommu/io-pgtable.c | 4 +
> drivers/iommu/io-pgtable.h | 6 +
> 5 files changed, 507 insertions(+)
> create mode 100644 drivers/iommu/io-pgtable-arm-short.c
>
> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index baa0d97..8e50e73 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -38,6 +38,13 @@ config IOMMU_IO_PGTABLE_LPAE_SELFTEST
>
> If unsure, say N here.
>
> +config IOMMU_IO_PGTABLE_SHORT
> + bool "ARMv7/v8 Short Descriptor Format"
> + select IOMMU_IO_PGTABLE
> + help
> + Enable support for the ARM Short descriptor pagetable format.
> + It has 2-levels pagetable and The allocator supports 4K/64K/1M/16M.
> +
> endmenu
>
> config IOMMU_IOVA
> diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
> index 080ffab..815b3c8 100644
> --- a/drivers/iommu/Makefile
> +++ b/drivers/iommu/Makefile
> @@ -3,6 +3,7 @@ obj-$(CONFIG_IOMMU_API) += iommu-traces.o
> obj-$(CONFIG_IOMMU_API) += iommu-sysfs.o
> obj-$(CONFIG_IOMMU_IO_PGTABLE) += io-pgtable.o
> obj-$(CONFIG_IOMMU_IO_PGTABLE_LPAE) += io-pgtable-arm.o
> +obj-$(CONFIG_IOMMU_IO_PGTABLE_SHORT) += io-pgtable-arm-short.o
> obj-$(CONFIG_IOMMU_IOVA) += iova.o
> obj-$(CONFIG_OF_IOMMU) += of_iommu.o
> obj-$(CONFIG_MSM_IOMMU) += msm_iommu.o msm_iommu_dev.o
> diff --git a/drivers/iommu/io-pgtable-arm-short.c b/drivers/iommu/io-pgtable-arm-short.c
> new file mode 100644
> index 0000000..8d723ec
> --- /dev/null
> +++ b/drivers/iommu/io-pgtable-arm-short.c
> @@ -0,0 +1,489 @@
> +/*
> + * Copyright (c) 2014-2015 MediaTek Inc.
> + * Author: Yong Wu <yong.wu@xxxxxxxxxxxx>
> + *
> + * 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.
> + */
> +#define pr_fmt(fmt) "arm-short-desc io-pgtable: "fmt
> +
> +#include <linux/err.h>
> +#include <linux/mm.h>
> +#include <linux/iommu.h>
> +#include <linux/errno.h>
> +
> +#include "io-pgtable.h"
> +
> +typedef u32 arm_short_iopte;
> +
> +struct arm_short_io_pgtable {
> + struct io_pgtable iop;
> + struct kmem_cache *ptekmem;
> + size_t pgd_size;
> + void *pgd;
> +};
> +
> +#define io_pgtable_short_to_data(x) \
> + container_of((x), struct arm_short_io_pgtable, iop)
> +
> +#define io_pgtable_ops_to_pgtable(x) \
> + container_of((x), struct io_pgtable, ops)
> +
> +#define io_pgtable_short_ops_to_data(x) \
> + io_pgtable_short_to_data(io_pgtable_ops_to_pgtable(x))
> +
> +#define ARM_SHORT_MAX_ADDR_BITS 32
> +
> +#define ARM_SHORT_PGDIR_SHIFT 20
> +#define ARM_SHORT_PAGE_SHIFT 12
> +#define ARM_SHORT_PTRS_PER_PTE 256
> +#define ARM_SHORT_BYTES_PER_PTE 1024
> +
> +/* 1 level pagetable */
> +#define ARM_SHORT_F_PGD_TYPE_PAGE (0x1)
> +#define ARM_SHORT_F_PGD_TYPE_PAGE_MSK (0x3)
> +#define ARM_SHORT_F_PGD_TYPE_SECTION (0x2)
> +#define ARM_SHORT_F_PGD_TYPE_SUPERSECTION (0x2 | (1 << 18))
> +#define ARM_SHORT_F_PGD_TYPE_SECTION_MSK (0x3 | (1 << 18))
> +#define ARM_SHORT_F_PGD_TYPE_IS_PAGE(pgd) (((pgd) & 0x3) == 1)
> +#define ARM_SHORT_F_PGD_TYPE_IS_SECTION(pgd) \
> + (((pgd) & ARM_SHORT_F_PGD_TYPE_SECTION_MSK) \
> + == ARM_SHORT_F_PGD_TYPE_SECTION)
> +#define ARM_SHORT_F_PGD_TYPE_IS_SUPERSECTION(pgd) \
> + (((pgd) & ARM_SHORT_F_PGD_TYPE_SECTION_MSK) \
> + == ARM_SHORT_F_PGD_TYPE_SUPERSECTION)
> +
> +#define ARM_SHORT_F_PGD_B_BIT BIT(2)
> +#define ARM_SHORT_F_PGD_C_BIT BIT(3)
> +#define ARM_SHORT_F_PGD_IMPLE_BIT BIT(9)
> +#define ARM_SHORT_F_PGD_S_BIT BIT(16)
> +#define ARM_SHORT_F_PGD_NG_BIT BIT(17)
> +#define ARM_SHORT_F_PGD_NS_BIT_PAGE BIT(3)
> +#define ARM_SHORT_F_PGD_NS_BIT_SECTION BIT(19)
> +
> +#define ARM_SHORT_F_PGD_PA_PAGETABLE_MSK 0xfffffc00
> +#define ARM_SHORT_F_PGD_PA_SECTION_MSK 0xfff00000
> +#define ARM_SHORT_F_PGD_PA_SUPERSECTION_MSK 0xff000000
> +
> +/* 2 level pagetable */
> +#define ARM_SHORT_F_PTE_TYPE_GET(val) ((val) & 0x3)
> +#define ARM_SHORT_F_PTE_TYPE_LARGE BIT(0)
> +#define ARM_SHORT_F_PTE_TYPE_SMALL BIT(1)
> +#define ARM_SHORT_F_PTE_B_BIT BIT(2)
> +#define ARM_SHORT_F_PTE_C_BIT BIT(3)
> +#define ARM_SHORT_F_PTE_IMPLE_BIT BIT(9)
> +#define ARM_SHORT_F_PTE_S_BIT BIT(10)
> +#define ARM_SHORT_F_PTE_PA_LARGE_MSK 0xffff0000
> +#define ARM_SHORT_F_PTE_PA_SMALL_MSK 0xfffff000
> +
> +#define ARM_SHORT_PGD_IDX(a) ((a) >> ARM_SHORT_PGDIR_SHIFT)
> +#define ARM_SHORT_PTE_IDX(a) \
> + (((a) >> ARM_SHORT_PAGE_SHIFT) & 0xff)
> +#define ARM_SHORT_GET_PTE_VA(pgd) \
> + (phys_to_virt((unsigned long)pgd & ARM_SHORT_F_PGD_PA_PAGETABLE_MSK))
> +
> +static arm_short_iopte *
> +arm_short_get_pte_in_pgd(arm_short_iopte curpgd, unsigned int iova)
> +{
> + arm_short_iopte *pte;
> +
> + pte = ARM_SHORT_GET_PTE_VA(curpgd);
> + pte += ARM_SHORT_PTE_IDX(iova);
> + return pte;
> +}
> +
> +static arm_short_iopte *
> +arm_short_supersection_start(arm_short_iopte *pgd)
> +{
> + return (arm_short_iopte *)(round_down((unsigned long)pgd, (16 * 4)));
> +}
> +
> +static int _arm_short_check_free_pte(struct arm_short_io_pgtable *data,
> + arm_short_iopte *pgd)
> +{
> + arm_short_iopte *pte;
> + int i;
> +
> + pte = ARM_SHORT_GET_PTE_VA(*pgd);
> +
> + for (i = 0; i < ARM_SHORT_PTRS_PER_PTE; i++) {
> + if (pte[i] != 0)
> + return 1;
> + }
> +
> + /* Free PTE */
> + kmem_cache_free(data->ptekmem, pte);
> + *pgd = 0;
> +
> + return 0;
> +}
> +
> +static phys_addr_t arm_short_iova_to_phys(struct io_pgtable_ops *ops,
> + unsigned long iova)
> +{
> + struct arm_short_io_pgtable *data = io_pgtable_short_ops_to_data(ops);
> + arm_short_iopte *pte, *pgd = data->pgd;
> + phys_addr_t pa = 0;
> +
> + pgd += ARM_SHORT_PGD_IDX(iova);
> +
> + if (ARM_SHORT_F_PGD_TYPE_IS_PAGE(*pgd)) {
> + pte = arm_short_get_pte_in_pgd(*pgd, iova);
> +
> + if (ARM_SHORT_F_PTE_TYPE_GET(*pte)
> + == ARM_SHORT_F_PTE_TYPE_LARGE) {
> + pa = (*pte) & ARM_SHORT_F_PTE_PA_LARGE_MSK;
> + pa |= iova & (~ARM_SHORT_F_PTE_PA_LARGE_MSK);
> + } else if (ARM_SHORT_F_PTE_TYPE_GET(*pte)
> + == ARM_SHORT_F_PTE_TYPE_SMALL) {

Would make it easier to read:
u8 pte_type;

[...]

pte_type = ARM_SHORT_F_PTE_TYPE_GET(*pte)
if (pte_type == ARM_SHORT_F_PTE_TYPE_LARGE) {
[...]
} else if (pte_type == ARM_SHORT_F_PTE_TYPE_SMALL) {
[...]
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/