The Allwinner H6 has introduced an IOMMU for a few DMA controllers, mostly
video related: the display engine, the video decoders / encoders, the
camera capture controller, etc.

The design is pretty simple compared to other IOMMUs found in SoCs: there's
a single instance, controlling all the masters, with a single address
space.

It also features a performance monitoring unit that allows to retrieve
various informations (per-master and global TLB accesses, hits and misses,
access latency, etc) that isn't supported at the moment.

Signed-off-by: Maxime Ripard <max...@cerno.tech>
---
 drivers/iommu/Kconfig        |    9 +-
 drivers/iommu/Makefile       |    1 +-
 drivers/iommu/sun50i-iommu.c | 1072 +++++++++++++++++++++++++++++++++++-
 3 files changed, 1082 insertions(+)
 create mode 100644 drivers/iommu/sun50i-iommu.c

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index d2fade984999..87677ea98427 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -302,6 +302,15 @@ config ROCKCHIP_IOMMU
          Say Y here if you are using a Rockchip SoC that includes an IOMMU
          device.
 
+config SUN50I_IOMMU
+       bool "Allwinner H6 IOMMU Support"
+       depends on ARCH_SUNXI || COMPILE_TEST
+       select ARM_DMA_USE_IOMMU
+       select IOMMU_API
+       select IOMMU_DMA
+       help
+         Support for the IOMMU introduced in the Allwinner H6 SoCs.
+
 config TEGRA_IOMMU_GART
        bool "Tegra GART IOMMU Support"
        depends on ARCH_TEGRA_2x_SOC
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index 2104fb8afc06..dd1ff336b9b9 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_MTK_IOMMU_V1) += mtk_iommu_v1.o
 obj-$(CONFIG_OMAP_IOMMU) += omap-iommu.o
 obj-$(CONFIG_OMAP_IOMMU_DEBUG) += omap-iommu-debug.o
 obj-$(CONFIG_ROCKCHIP_IOMMU) += rockchip-iommu.o
+obj-$(CONFIG_SUN50I_IOMMU) += sun50i-iommu.o
 obj-$(CONFIG_TEGRA_IOMMU_GART) += tegra-gart.o
 obj-$(CONFIG_TEGRA_IOMMU_SMMU) += tegra-smmu.o
 obj-$(CONFIG_EXYNOS_IOMMU) += exynos-iommu.o
diff --git a/drivers/iommu/sun50i-iommu.c b/drivers/iommu/sun50i-iommu.c
new file mode 100644
index 000000000000..81ba5f562bd2
--- /dev/null
+++ b/drivers/iommu/sun50i-iommu.c
@@ -0,0 +1,1072 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+// Copyright (C) 2016-2018, Allwinner Technology CO., LTD.
+// Copyright (C) 2019-2020, Cerno
+
+#include <linux/bitfield.h>
+#include <linux/bug.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/dma-direction.h>
+#include <linux/dma-iommu.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/iommu.h>
+#include <linux/iopoll.h>
+#include <linux/ioport.h>
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+#define IOMMU_RESET_REG                        0x010
+#define IOMMU_ENABLE_REG               0x020
+#define IOMMU_ENABLE_ENABLE                    BIT(0)
+
+#define IOMMU_BYPASS_REG               0x030
+#define IOMMU_AUTO_GATING_REG          0x040
+#define IOMMU_AUTO_GATING_ENABLE               BIT(0)
+
+#define IOMMU_WBUF_CTRL_REG            0x044
+#define IOMMU_OOO_CTRL_REG             0x048
+#define IOMMU_4KB_BDY_PRT_CTRL_REG     0x04c
+#define IOMMU_TTB_REG                  0x050
+#define IOMMU_TLB_ENABLE_REG           0x060
+#define IOMMU_TLB_PREFETCH_REG         0x070
+#define IOMMU_TLB_PREFETCH_MASTER_ENABLE(m)    BIT(m)
+
+#define IOMMU_TLB_FLUSH_REG            0x080
+#define IOMMU_TLB_FLUSH_PTW_CACHE              BIT(17)
+#define IOMMU_TLB_FLUSH_MACRO_TLB              BIT(16)
+#define IOMMU_TLB_FLUSH_MICRO_TLB(i)           (BIT(i) & GENMASK(5, 0))
+
+#define IOMMU_TLB_IVLD_ADDR_REG                0x090
+#define IOMMU_TLB_IVLD_ADDR_MASK_REG   0x094
+#define IOMMU_TLB_IVLD_ENABLE_REG      0x098
+#define IOMMU_TLB_IVLD_ENABLE_ENABLE           BIT(0)
+
+#define IOMMU_PC_IVLD_ADDR_REG         0x0a0
+#define IOMMU_PC_IVLD_ENABLE_REG       0x0a8
+#define IOMMU_PC_IVLD_ENABLE_ENABLE            BIT(0)
+
+#define IOMMU_DM_AUT_CTRL_REG(d)       (0x0b0 + ((d) / 2) * 4)
+#define IOMMU_DM_AUT_CTRL_RD_UNAVAIL(d, m)     (1 << (((d & 1) * 16) + ((m) * 
2)))
+#define IOMMU_DM_AUT_CTRL_WR_UNAVAIL(d, m)     (1 << (((d & 1) * 16) + ((m) * 
2) + 1))
+
+#define IOMMU_DM_AUT_OVWT_REG          0x0d0
+#define IOMMU_INT_ENABLE_REG           0x100
+#define IOMMU_INT_CLR_REG              0x104
+#define IOMMU_INT_STA_REG              0x108
+#define IOMMU_INT_ERR_ADDR_REG(i)      (0x110 + (i) * 4)
+#define IOMMU_INT_ERR_ADDR_L1_REG      0x130
+#define IOMMU_INT_ERR_ADDR_L2_REG      0x134
+#define IOMMU_INT_ERR_DATA_REG(i)      (0x150 + (i) * 4)
+#define IOMMU_L1PG_INT_REG             0x0180
+#define IOMMU_L2PG_INT_REG             0x0184
+
+#define IOMMU_INT_INVALID_L2PG                 BIT(17)
+#define IOMMU_INT_INVALID_L1PG                 BIT(16)
+#define IOMMU_INT_MASTER_PERMISSION(m)         BIT(m)
+#define IOMMU_INT_MASTER_MASK                  (IOMMU_INT_MASTER_PERMISSION(0) 
| \
+                                                IOMMU_INT_MASTER_PERMISSION(1) 
| \
+                                                IOMMU_INT_MASTER_PERMISSION(2) 
| \
+                                                IOMMU_INT_MASTER_PERMISSION(3) 
| \
+                                                IOMMU_INT_MASTER_PERMISSION(4) 
| \
+                                                IOMMU_INT_MASTER_PERMISSION(5))
+#define IOMMU_INT_MASK                         (IOMMU_INT_INVALID_L1PG | \
+                                                IOMMU_INT_INVALID_L2PG | \
+                                                IOMMU_INT_MASTER_MASK)
+
+#define PT_ENTRY_SIZE                  sizeof(u32)
+
+#define NUM_DT_ENTRIES                 4096
+#define DT_SIZE                                (NUM_DT_ENTRIES * PT_ENTRY_SIZE)
+
+#define NUM_PT_ENTRIES                 256
+#define PT_SIZE                                (NUM_PT_ENTRIES * PT_ENTRY_SIZE)
+
+struct sun50i_iommu {
+       struct iommu_device iommu;
+
+       /* Lock to modify the IOMMU registers */
+       spinlock_t iommu_lock;
+
+       struct device *dev;
+       void __iomem *base;
+       struct reset_control *reset;
+       struct clk *clk;
+
+       struct iommu_domain *domain;
+       struct iommu_group *group;
+       struct kmem_cache *pt_pool;
+};
+
+struct sun50i_iommu_domain {
+       struct iommu_domain domain;
+
+       /* Number of devices attached to the domain */
+       refcount_t refcnt;
+
+       /* Lock to modify the Directory Table */
+       spinlock_t dt_lock;
+
+       /* L1 Page Table */
+       u32 *dt;
+       dma_addr_t dt_dma;
+
+       struct sun50i_iommu *iommu;
+};
+
+static struct sun50i_iommu_domain *to_sun50i_domain(struct iommu_domain 
*domain)
+{
+       return container_of(domain, struct sun50i_iommu_domain, domain);
+}
+
+static struct sun50i_iommu *sun50i_iommu_from_dev(struct device *dev)
+{
+       struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+
+       if (!fwspec)
+               return NULL;
+
+       return fwspec->iommu_priv;
+}
+
+static u32 iommu_read(struct sun50i_iommu *iommu, u32 offset)
+{
+       return readl(iommu->base + offset);
+}
+
+static void iommu_write(struct sun50i_iommu *iommu, u32 offset, u32 value)
+{
+       writel(value, iommu->base + offset);
+}
+
+/*
+ * The Allwinner H6 IOMMU uses a 2-level page table.
+ *
+ * The first level is the usual Directory Table (DT), that consists of
+ * 4096 4-bytes Directory Table Entries (DTE), each pointing to a Page
+ * Table (PT).
+ *
+ * Each PT consits of 256 4-bytes Page Table Entries (PTE), each
+ * pointing to a 4kB page of physical memory.
+ *
+ * The IOMMU supports a single DT, pointed by the IOMMU_TTB_REG
+ * register that contains its physical address.
+ */
+
+#define SUN50I_IOVA_DTE_MASK   GENMASK(31, 20)
+#define SUN50I_IOVA_PTE_MASK   GENMASK(19, 12)
+#define SUN50I_IOVA_PAGE_MASK  GENMASK(11, 0)
+
+static u32 sun50i_iova_get_dte_index(dma_addr_t iova)
+{
+       return FIELD_GET(SUN50I_IOVA_DTE_MASK, iova);
+}
+
+static u32 sun50i_iova_get_pte_index(dma_addr_t iova)
+{
+       return FIELD_GET(SUN50I_IOVA_PTE_MASK, iova);
+}
+
+static u32 sun50i_iova_get_page_offset(dma_addr_t iova)
+{
+       return FIELD_GET(SUN50I_IOVA_PAGE_MASK, iova);
+}
+
+/*
+ * Each Directory Table Entry has a Page Table address and a valid
+ * bit:
+
+ * +---------------------+-----------+-+
+ * | PT address          | Reserved  |V|
+ * +---------------------+-----------+-+
+ *  31:10 - Page Table address
+ *   9:2  - Reserved
+ *   1:0  - 1 if the entry is valid
+ */
+
+#define SUN50I_DTE_PT_ADDRESS_MASK     GENMASK(31, 10)
+#define SUN50I_DTE_PT_ATTRS            GENMASK(1, 0)
+#define SUN50I_DTE_PT_VALID            1
+
+static phys_addr_t sun50i_dte_get_pt_address(u32 dte)
+{
+       return (phys_addr_t)dte & SUN50I_DTE_PT_ADDRESS_MASK;
+}
+
+static bool sun50i_dte_is_pt_valid(u32 dte)
+{
+       return (dte & SUN50I_DTE_PT_ATTRS) == SUN50I_DTE_PT_VALID;
+}
+
+static u32 sun50i_mk_dte(dma_addr_t pt_dma)
+{
+       return (pt_dma & SUN50I_DTE_PT_ADDRESS_MASK) | SUN50I_DTE_PT_VALID;
+}
+
+/*
+ * Each PTE has a Page address, an authority index and a valid bit:
+ *
+ * +----------------+-----+-----+-----+---+-----+
+ * | Page address   | Rsv | ACI | Rsv | V | Rsv |
+ * +----------------+-----+-----+-----+---+-----+
+ *  31:12 - Page address
+ *  11:8  - Reserved
+ *   7:4  - Authority Control Index
+ *   3:2  - Reserved
+ *     1  - 1 if the entry is valid
+ *     0  - Reserved
+ *
+ * The way permissions work is that the IOMMU has 16 "domains" that
+ * can be configured to give each masters either read or write
+ * permissions through the IOMMU_DM_AUT_CTRL_REG registers. The domain
+ * 0 seems like the default domain, and its permissions in the
+ * IOMMU_DM_AUT_CTRL_REG are only read-only, so it's not really
+ * useful to enforce any particular permission.
+ *
+ * Each page entry will then have a reference to the domain they are
+ * affected to, so that we can actually enforce them on a per-page
+ * basis.
+ *
+ * In order to make it work with the IOMMU framework, we will be using
+ * 4 different domains, starting at 1: RD_WR, RD, WR and NONE
+ * depending on the permission we want to enforce. Each domain will
+ * have each master setup in the same way, since the IOMMU framework
+ * doesn't seem to restrict page access on a per-device basis. And
+ * then we will use the relevant domain index when generating the page
+ * table entry depending on the permissions we want to be enforced.
+ */
+
+enum sun50i_iommu_aci {
+       SUN50I_IOMMU_ACI_DO_NOT_USE = 0,
+       SUN50I_IOMMU_ACI_NONE,
+       SUN50I_IOMMU_ACI_RD,
+       SUN50I_IOMMU_ACI_WR,
+       SUN50I_IOMMU_ACI_RD_WR,
+};
+
+#define SUN50I_PTE_PAGE_ADDRESS_MASK   GENMASK(31, 12)
+#define SUN50I_PTE_ACI_MASK            GENMASK(7, 4)
+#define SUN50I_PTE_PAGE_VALID          BIT(1)
+
+static phys_addr_t sun50i_pte_get_page_address(u32 pte)
+{
+       return (phys_addr_t)pte & SUN50I_PTE_PAGE_ADDRESS_MASK;
+}
+
+static enum sun50i_iommu_aci sun50i_get_pte_aci(u32 pte)
+{
+       return FIELD_GET(SUN50I_PTE_ACI_MASK, pte);
+}
+
+static bool sun50i_pte_is_page_valid(u32 pte)
+{
+       return pte & SUN50I_PTE_PAGE_VALID;
+}
+
+static u32 sun50i_mk_pte(phys_addr_t page, int prot)
+{
+       enum sun50i_iommu_aci aci;
+       u32 flags = 0;
+
+       if (prot & (IOMMU_READ | IOMMU_WRITE))
+               aci = SUN50I_IOMMU_ACI_RD_WR;
+       else if (prot & IOMMU_READ)
+               aci = SUN50I_IOMMU_ACI_RD;
+       else if (prot & IOMMU_WRITE)
+               aci = SUN50I_IOMMU_ACI_WR;
+       else
+               aci = SUN50I_IOMMU_ACI_NONE;
+
+       flags |= FIELD_PREP(SUN50I_PTE_ACI_MASK, aci);
+       page &= SUN50I_PTE_PAGE_ADDRESS_MASK;
+       return page | flags | SUN50I_PTE_PAGE_VALID;
+}
+
+static void sun50i_table_flush(struct sun50i_iommu_domain *sun50i_domain,
+                              void *vaddr, unsigned int count)
+{
+       struct sun50i_iommu *iommu = sun50i_domain->iommu;
+       dma_addr_t dma = virt_to_phys(vaddr);
+       size_t size = count * PT_ENTRY_SIZE;
+
+       dma_sync_single_for_device(iommu->dev, dma, size, DMA_TO_DEVICE);
+}
+
+static int sun50i_iommu_flush_all_tlb(struct sun50i_iommu *iommu)
+{
+       u32 reg;
+       int ret;
+
+       assert_spin_locked(&iommu->iommu_lock);
+
+       iommu_write(iommu,
+                   IOMMU_TLB_FLUSH_REG,
+                   IOMMU_TLB_FLUSH_PTW_CACHE |
+                   IOMMU_TLB_FLUSH_MACRO_TLB |
+                   IOMMU_TLB_FLUSH_MICRO_TLB(5) |
+                   IOMMU_TLB_FLUSH_MICRO_TLB(4) |
+                   IOMMU_TLB_FLUSH_MICRO_TLB(3) |
+                   IOMMU_TLB_FLUSH_MICRO_TLB(2) |
+                   IOMMU_TLB_FLUSH_MICRO_TLB(1) |
+                   IOMMU_TLB_FLUSH_MICRO_TLB(0));
+
+       ret = readl_poll_timeout(iommu->base + IOMMU_TLB_FLUSH_REG,
+                                reg, !reg,
+                                1, 2000);
+       if (ret)
+               dev_err(iommu->dev, "Enable flush all request timed out\n");
+
+       return ret;
+}
+
+static int sun50i_iommu_tlb_invalidate(struct sun50i_iommu *iommu,
+                                      dma_addr_t iova)
+{
+       int ret;
+       u32 reg;
+
+       assert_spin_locked(&iommu->iommu_lock);
+
+       iommu_write(iommu, IOMMU_TLB_IVLD_ADDR_REG, iova);
+       iommu_write(iommu, IOMMU_TLB_IVLD_ADDR_MASK_REG,
+                   SUN50I_PTE_PAGE_ADDRESS_MASK);
+       iommu_write(iommu, IOMMU_TLB_IVLD_ENABLE_REG,
+                   IOMMU_TLB_IVLD_ENABLE_ENABLE);
+
+       ret = readl_poll_timeout(iommu->base + IOMMU_TLB_IVLD_ENABLE_REG,
+                                reg, !(reg & IOMMU_TLB_IVLD_ENABLE_ENABLE),
+                                1, 2000);
+       if (ret)
+               dev_err(iommu->dev, "TLB Invalid timed out\n");
+
+       return ret;
+}
+
+static int sun50i_iommu_ptw_invalidate(struct sun50i_iommu *iommu,
+                                      dma_addr_t iova)
+{
+       int ret;
+       u32 reg;
+
+       assert_spin_locked(&iommu->iommu_lock);
+
+       iommu_write(iommu, IOMMU_PC_IVLD_ADDR_REG, iova);
+       iommu_write(iommu, IOMMU_PC_IVLD_ENABLE_REG,
+                   IOMMU_PC_IVLD_ENABLE_ENABLE);
+
+       ret = readl_poll_timeout(iommu->base + IOMMU_PC_IVLD_ENABLE_REG,
+                                reg, !(reg & IOMMU_PC_IVLD_ENABLE_ENABLE),
+                                1, 2000);
+       if (ret)
+               dev_err(iommu->dev, "PTW cache invalid timed out\n");
+
+       return ret;
+}
+
+static int sun50i_iommu_enable(struct sun50i_iommu *iommu)
+{
+       struct sun50i_iommu_domain *sun50i_domain;
+       unsigned long flags;
+       int ret;
+
+       if (!iommu->domain)
+               return 0;
+
+       sun50i_domain = to_sun50i_domain(iommu->domain);
+
+       ret = reset_control_deassert(iommu->reset);
+       if (ret)
+               return ret;
+
+       ret = clk_prepare_enable(iommu->clk);
+       if (ret)
+               goto err_reset_assert;
+
+       spin_lock_irqsave(&iommu->iommu_lock, flags);
+
+       iommu_write(iommu, IOMMU_TTB_REG, sun50i_domain->dt_dma);
+       iommu_write(iommu, IOMMU_TLB_PREFETCH_REG,
+                   IOMMU_TLB_PREFETCH_MASTER_ENABLE(0) |
+                   IOMMU_TLB_PREFETCH_MASTER_ENABLE(1) |
+                   IOMMU_TLB_PREFETCH_MASTER_ENABLE(2) |
+                   IOMMU_TLB_PREFETCH_MASTER_ENABLE(3) |
+                   IOMMU_TLB_PREFETCH_MASTER_ENABLE(4) |
+                   IOMMU_TLB_PREFETCH_MASTER_ENABLE(5));
+       iommu_write(iommu, IOMMU_INT_ENABLE_REG, IOMMU_INT_MASK);
+       iommu_write(iommu, IOMMU_DM_AUT_CTRL_REG(SUN50I_IOMMU_ACI_NONE),
+                   IOMMU_DM_AUT_CTRL_RD_UNAVAIL(SUN50I_IOMMU_ACI_NONE, 0) |
+                   IOMMU_DM_AUT_CTRL_WR_UNAVAIL(SUN50I_IOMMU_ACI_NONE, 0) |
+                   IOMMU_DM_AUT_CTRL_RD_UNAVAIL(SUN50I_IOMMU_ACI_NONE, 1) |
+                   IOMMU_DM_AUT_CTRL_WR_UNAVAIL(SUN50I_IOMMU_ACI_NONE, 1) |
+                   IOMMU_DM_AUT_CTRL_RD_UNAVAIL(SUN50I_IOMMU_ACI_NONE, 2) |
+                   IOMMU_DM_AUT_CTRL_WR_UNAVAIL(SUN50I_IOMMU_ACI_NONE, 2) |
+                   IOMMU_DM_AUT_CTRL_RD_UNAVAIL(SUN50I_IOMMU_ACI_NONE, 3) |
+                   IOMMU_DM_AUT_CTRL_WR_UNAVAIL(SUN50I_IOMMU_ACI_NONE, 3) |
+                   IOMMU_DM_AUT_CTRL_RD_UNAVAIL(SUN50I_IOMMU_ACI_NONE, 4) |
+                   IOMMU_DM_AUT_CTRL_WR_UNAVAIL(SUN50I_IOMMU_ACI_NONE, 4) |
+                   IOMMU_DM_AUT_CTRL_RD_UNAVAIL(SUN50I_IOMMU_ACI_NONE, 5) |
+                   IOMMU_DM_AUT_CTRL_WR_UNAVAIL(SUN50I_IOMMU_ACI_NONE, 5));
+
+       iommu_write(iommu, IOMMU_DM_AUT_CTRL_REG(SUN50I_IOMMU_ACI_RD),
+                   IOMMU_DM_AUT_CTRL_WR_UNAVAIL(SUN50I_IOMMU_ACI_RD, 0) |
+                   IOMMU_DM_AUT_CTRL_WR_UNAVAIL(SUN50I_IOMMU_ACI_RD, 1) |
+                   IOMMU_DM_AUT_CTRL_WR_UNAVAIL(SUN50I_IOMMU_ACI_RD, 2) |
+                   IOMMU_DM_AUT_CTRL_WR_UNAVAIL(SUN50I_IOMMU_ACI_RD, 3) |
+                   IOMMU_DM_AUT_CTRL_WR_UNAVAIL(SUN50I_IOMMU_ACI_RD, 4) |
+                   IOMMU_DM_AUT_CTRL_WR_UNAVAIL(SUN50I_IOMMU_ACI_RD, 5));
+
+       iommu_write(iommu, IOMMU_DM_AUT_CTRL_REG(SUN50I_IOMMU_ACI_WR),
+                   IOMMU_DM_AUT_CTRL_RD_UNAVAIL(SUN50I_IOMMU_ACI_WR, 0) |
+                   IOMMU_DM_AUT_CTRL_RD_UNAVAIL(SUN50I_IOMMU_ACI_WR, 1) |
+                   IOMMU_DM_AUT_CTRL_RD_UNAVAIL(SUN50I_IOMMU_ACI_WR, 2) |
+                   IOMMU_DM_AUT_CTRL_RD_UNAVAIL(SUN50I_IOMMU_ACI_WR, 3) |
+                   IOMMU_DM_AUT_CTRL_RD_UNAVAIL(SUN50I_IOMMU_ACI_WR, 4) |
+                   IOMMU_DM_AUT_CTRL_RD_UNAVAIL(SUN50I_IOMMU_ACI_WR, 5));
+
+       ret = sun50i_iommu_flush_all_tlb(iommu);
+       if (ret) {
+               spin_unlock_irqrestore(&iommu->iommu_lock, flags);
+               goto err_clk_disable;
+       }
+
+       iommu_write(iommu, IOMMU_AUTO_GATING_REG, IOMMU_AUTO_GATING_ENABLE);
+       iommu_write(iommu, IOMMU_ENABLE_REG, IOMMU_ENABLE_ENABLE);
+
+       spin_unlock_irqrestore(&iommu->iommu_lock, flags);
+
+       return 0;
+
+err_clk_disable:
+       clk_disable_unprepare(iommu->clk);
+
+err_reset_assert:
+       reset_control_assert(iommu->reset);
+
+       return ret;
+}
+
+static void sun50i_iommu_disable(struct sun50i_iommu *iommu)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&iommu->iommu_lock, flags);
+
+       iommu_write(iommu, IOMMU_ENABLE_REG, 0);
+       iommu_write(iommu, IOMMU_TTB_REG, 0);
+
+       spin_unlock_irqrestore(&iommu->iommu_lock, flags);
+
+       clk_disable_unprepare(iommu->clk);
+       reset_control_assert(iommu->reset);
+}
+
+static u32 *sun50i_dte_get_page_table(struct sun50i_iommu_domain 
*sun50i_domain,
+                                     dma_addr_t iova, gfp_t gfp)
+{
+       struct sun50i_iommu *iommu = sun50i_domain->iommu;
+       unsigned long flags;
+       dma_addr_t pt_dma;
+       u32 *page_table;
+       u32 *dte_addr;
+       u32 dte;
+
+       assert_spin_locked(&sun50i_domain->dt_lock);
+
+       dte_addr = &sun50i_domain->dt[sun50i_iova_get_dte_index(iova)];
+       dte = *dte_addr;
+       if (sun50i_dte_is_pt_valid(dte)) {
+               phys_addr_t pt_phys = sun50i_dte_get_pt_address(dte);
+               return (u32 *)phys_to_virt(pt_phys);
+       }
+
+       page_table = kmem_cache_zalloc(iommu->pt_pool, gfp);
+       if (!page_table)
+               return ERR_PTR(-ENOMEM);
+
+       pt_dma = dma_map_single(iommu->dev, page_table, PT_SIZE, DMA_TO_DEVICE);
+       if (dma_mapping_error(iommu->dev, pt_dma)) {
+               dev_err(iommu->dev, "Couldn't map L2 Page Table\n");
+               kmem_cache_free(iommu->pt_pool, page_table);
+               return ERR_PTR(-ENOMEM);
+       }
+
+       /* We rely on the physical address and DMA address being the same */
+       WARN_ON(pt_dma != virt_to_phys(page_table));
+
+       dte = sun50i_mk_dte(pt_dma);
+       *dte_addr = dte;
+       sun50i_table_flush(sun50i_domain, page_table, PT_SIZE);
+       sun50i_table_flush(sun50i_domain, dte_addr, 1);
+
+       spin_lock_irqsave(&iommu->iommu_lock, flags);
+       sun50i_iommu_ptw_invalidate(iommu, iova);
+       spin_unlock_irqrestore(&iommu->iommu_lock, flags);
+
+       return page_table;
+}
+
+static int sun50i_iommu_map(struct iommu_domain *domain, unsigned long iova,
+                           phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
+{
+       struct sun50i_iommu_domain *sun50i_domain = to_sun50i_domain(domain);
+       struct sun50i_iommu *iommu = sun50i_domain->iommu;
+       u32 pte_index;
+       u32 *page_table, *pte_addr;
+       unsigned long flags;
+       int ret = 0;
+
+       spin_lock_irqsave(&sun50i_domain->dt_lock, flags);
+       page_table = sun50i_dte_get_page_table(sun50i_domain, iova, gfp);
+       if (IS_ERR(page_table)) {
+               ret = PTR_ERR(page_table);
+               goto out;
+       }
+
+       pte_index = sun50i_iova_get_pte_index(iova);
+       pte_addr = &page_table[pte_index];
+       if (sun50i_pte_is_page_valid(*pte_addr)) {
+               phys_addr_t page_phys = sun50i_pte_get_page_address(*pte_addr);
+               dev_err(iommu->dev,
+                       "iova %pad already mapped to %pa cannot remap to %pa 
prot: %#x\n",
+                       &iova, &page_phys, &paddr, prot);
+               ret = -EBUSY;
+               goto out;
+       }
+
+       *pte_addr = sun50i_mk_pte(paddr, prot);
+       sun50i_table_flush(sun50i_domain, pte_addr, 1);
+
+       spin_lock_irqsave(&iommu->iommu_lock, flags);
+       sun50i_iommu_tlb_invalidate(iommu, iova);
+       spin_unlock_irqrestore(&iommu->iommu_lock, flags);
+
+out:
+       spin_unlock_irqrestore(&sun50i_domain->dt_lock, flags);
+       return ret;
+}
+
+static size_t sun50i_iommu_unmap(struct iommu_domain *domain, unsigned long 
iova,
+                                size_t size, struct iommu_iotlb_gather *gather)
+{
+       struct sun50i_iommu_domain *sun50i_domain = to_sun50i_domain(domain);
+       struct sun50i_iommu *iommu = sun50i_domain->iommu;
+       unsigned long flags;
+       phys_addr_t pt_phys;
+       dma_addr_t pte_dma;
+       u32 *pte_addr;
+       u32 dte;
+
+       spin_lock_irqsave(&sun50i_domain->dt_lock, flags);
+
+       dte = sun50i_domain->dt[sun50i_iova_get_dte_index(iova)];
+       if (!sun50i_dte_is_pt_valid(dte)) {
+               spin_unlock_irqrestore(&sun50i_domain->dt_lock, flags);
+               return 0;
+       }
+
+       pt_phys = sun50i_dte_get_pt_address(dte);
+       pte_addr = (u32 *)phys_to_virt(pt_phys) + 
sun50i_iova_get_pte_index(iova);
+       pte_dma = pt_phys + sun50i_iova_get_pte_index(iova) * PT_ENTRY_SIZE;
+
+       if (!sun50i_pte_is_page_valid(*pte_addr)) {
+               spin_unlock_irqrestore(&sun50i_domain->dt_lock, flags);
+               return 0;
+       }
+
+       memset(pte_addr, 0, sizeof(*pte_addr));
+       sun50i_table_flush(sun50i_domain, pte_addr, 1);
+
+       spin_lock(&iommu->iommu_lock);
+       sun50i_iommu_tlb_invalidate(iommu, iova);
+       sun50i_iommu_ptw_invalidate(iommu, iova);
+       spin_unlock(&iommu->iommu_lock);
+
+       spin_unlock_irqrestore(&sun50i_domain->dt_lock, flags);
+
+       return SZ_4K;
+}
+
+static phys_addr_t sun50i_iommu_iova_to_phys(struct iommu_domain *domain,
+                                            dma_addr_t iova)
+{
+       struct sun50i_iommu_domain *sun50i_domain = to_sun50i_domain(domain);
+       phys_addr_t pt_phys, phys = 0;
+       unsigned long flags;
+       u32 *page_table;
+       u32 dte, pte;
+
+       spin_lock_irqsave(&sun50i_domain->dt_lock, flags);
+
+       dte = sun50i_domain->dt[sun50i_iova_get_dte_index(iova)];
+       if (!sun50i_dte_is_pt_valid(dte))
+               goto out;
+
+       pt_phys = sun50i_dte_get_pt_address(dte);
+       page_table = (u32 *)phys_to_virt(pt_phys);
+       pte = page_table[sun50i_iova_get_pte_index(iova)];
+       if (!sun50i_pte_is_page_valid(pte))
+               goto out;
+
+       phys = sun50i_pte_get_page_address(pte) +
+               sun50i_iova_get_page_offset(iova);
+
+out:
+       spin_unlock_irqrestore(&sun50i_domain->dt_lock, flags);
+       return phys;
+}
+
+static struct iommu_domain *sun50i_iommu_domain_alloc(unsigned type)
+{
+       struct sun50i_iommu_domain *sun50i_domain;
+
+       if (type != IOMMU_DOMAIN_DMA && type != IOMMU_DOMAIN_UNMANAGED)
+               return NULL;
+
+       sun50i_domain = kzalloc(sizeof(*sun50i_domain), GFP_KERNEL);
+       if (!sun50i_domain)
+               return NULL;
+
+       if (type == IOMMU_DOMAIN_DMA &&
+           iommu_get_dma_cookie(&sun50i_domain->domain))
+               goto err_free_domain;
+
+       sun50i_domain->dt = (u32 *)__get_free_pages(GFP_KERNEL,
+                                                   get_order(DT_SIZE));
+       if (!sun50i_domain->dt)
+               goto err_put_cookie;
+       memset(sun50i_domain->dt, 0, DT_SIZE);
+
+       refcount_set(&sun50i_domain->refcnt, 1);
+       spin_lock_init(&sun50i_domain->dt_lock);
+
+       sun50i_domain->domain.geometry.aperture_start = 0;
+       sun50i_domain->domain.geometry.aperture_end = DMA_BIT_MASK(32);
+       sun50i_domain->domain.geometry.force_aperture = true;
+
+       return &sun50i_domain->domain;
+
+err_put_cookie:
+       if (type == IOMMU_DOMAIN_DMA)
+               iommu_put_dma_cookie(&sun50i_domain->domain);
+
+err_free_domain:
+       kfree(sun50i_domain);
+
+       return NULL;
+}
+
+static void sun50i_iommu_domain_free(struct iommu_domain *domain)
+{
+       struct sun50i_iommu_domain *sun50i_domain = to_sun50i_domain(domain);
+       unsigned long flags;
+
+       spin_lock_irqsave(&sun50i_domain->dt_lock, flags);
+       free_pages((unsigned long)sun50i_domain->dt, get_order(DT_SIZE));
+       sun50i_domain->dt = NULL;
+
+       spin_unlock_irqrestore(&sun50i_domain->dt_lock, flags);
+       iommu_put_dma_cookie(domain);
+
+       kfree(sun50i_domain);
+}
+
+static int sun50i_iommu_attach_domain(struct sun50i_iommu *iommu,
+                                     struct sun50i_iommu_domain *sun50i_domain)
+{
+       iommu->domain = &sun50i_domain->domain;
+       sun50i_domain->iommu = iommu;
+
+       sun50i_domain->dt_dma = dma_map_single(iommu->dev, sun50i_domain->dt,
+                                              DT_SIZE, DMA_TO_DEVICE);
+       if (dma_mapping_error(iommu->dev, sun50i_domain->dt_dma)) {
+               dev_err(iommu->dev, "Couldn't map L1 Page Table\n");
+               return -ENOMEM;
+       }
+
+       return sun50i_iommu_enable(iommu);
+}
+
+static void sun50i_iommu_detach_domain(struct sun50i_iommu *iommu,
+                                      struct sun50i_iommu_domain 
*sun50i_domain)
+{
+       unsigned long flags;
+       unsigned int i;
+
+       spin_lock_irqsave(&sun50i_domain->dt_lock, flags);
+
+       for (i = 0; i < NUM_DT_ENTRIES; i++) {
+               phys_addr_t pt_phys;
+               u32 *page_table;
+               u32 *dte_addr;
+               u32 dte;
+
+               dte_addr = &sun50i_domain->dt[i];
+               dte = *dte_addr;
+               if (!sun50i_dte_is_pt_valid(dte))
+                       continue;
+
+               memset(dte_addr, 0, sizeof(*dte_addr));
+               sun50i_table_flush(sun50i_domain, dte_addr, 1);
+
+               pt_phys = sun50i_dte_get_pt_address(dte);
+               dma_unmap_single(iommu->dev, pt_phys, PT_SIZE, DMA_TO_DEVICE);
+
+               page_table = phys_to_virt(pt_phys);
+               kmem_cache_free(iommu->pt_pool, page_table);
+       }
+
+       spin_unlock_irqrestore(&sun50i_domain->dt_lock, flags);
+
+       sun50i_iommu_disable(iommu);
+
+       dma_unmap_single(iommu->dev, virt_to_phys(sun50i_domain->dt),
+                        DT_SIZE, DMA_TO_DEVICE);
+
+       iommu->domain = NULL;
+}
+
+static void sun50i_iommu_detach_device(struct iommu_domain *domain,
+                                      struct device *dev)
+{
+       struct sun50i_iommu_domain *sun50i_domain = to_sun50i_domain(domain);
+       struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+       struct sun50i_iommu *iommu = fwspec->iommu_priv;
+
+       dev_dbg(dev, "Detaching from IOMMU domain\n");
+
+       if (iommu->domain != domain)
+               return;
+
+       if (refcount_dec_and_test(&sun50i_domain->refcnt))
+               sun50i_iommu_detach_domain(iommu, sun50i_domain);
+}
+
+static int sun50i_iommu_attach_device(struct iommu_domain *domain,
+                                     struct device *dev)
+{
+       struct sun50i_iommu_domain *sun50i_domain = to_sun50i_domain(domain);
+       struct sun50i_iommu *iommu;
+
+       iommu = sun50i_iommu_from_dev(dev);
+       if (!iommu)
+               return -ENODEV;
+
+       dev_dbg(dev, "Attaching to IOMMU domain\n");
+
+       refcount_inc(&sun50i_domain->refcnt);
+
+       if (iommu->domain == domain)
+               return 0;
+
+       if (iommu->domain)
+               sun50i_iommu_detach_device(iommu->domain, dev);
+
+       sun50i_iommu_attach_domain(iommu, sun50i_domain);
+
+       return 0;
+}
+
+static int sun50i_iommu_add_device(struct device *dev)
+{
+       struct sun50i_iommu *iommu;
+       struct iommu_group *group;
+
+       iommu = sun50i_iommu_from_dev(dev);
+       if (!iommu)
+               return -ENODEV;
+
+       group = iommu_group_get_for_dev(dev);
+       if (IS_ERR(group))
+               return PTR_ERR(group);
+
+       iommu_group_put(group);
+
+       return 0;
+}
+
+static void sun50i_iommu_remove_device(struct device *dev)
+{
+       iommu_group_remove_device(dev);
+}
+
+static struct iommu_group *sun50i_iommu_device_group(struct device *dev)
+{
+       struct sun50i_iommu *iommu = sun50i_iommu_from_dev(dev);
+
+       return iommu_group_ref_get(iommu->group);
+}
+
+static int sun50i_iommu_of_xlate(struct device *dev,
+                                struct of_phandle_args *args)
+{
+       struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+       struct platform_device *iommu_pdev = of_find_device_by_node(args->np);
+       unsigned id = args->args[0];
+
+       fwspec->iommu_priv = platform_get_drvdata(iommu_pdev);
+
+       return iommu_fwspec_add_ids(dev, &id, 1);
+}
+
+static struct iommu_ops sun50i_iommu_ops = {
+       .pgsize_bitmap = SZ_4K,
+       .map  = sun50i_iommu_map,
+       .unmap = sun50i_iommu_unmap,
+       .domain_alloc = sun50i_iommu_domain_alloc,
+       .domain_free = sun50i_iommu_domain_free,
+       .attach_dev = sun50i_iommu_attach_device,
+       .detach_dev = sun50i_iommu_detach_device,
+       .add_device = sun50i_iommu_add_device,
+       .remove_device = sun50i_iommu_remove_device,
+       .device_group   = sun50i_iommu_device_group,
+       .of_xlate = sun50i_iommu_of_xlate,
+       .iova_to_phys = sun50i_iommu_iova_to_phys,
+};
+
+static void sun50i_iommu_report_fault(struct sun50i_iommu *iommu,
+                                     unsigned master, phys_addr_t iova,
+                                     unsigned prot)
+{
+       dev_err(iommu->dev, "Page fault for %pad (master %d, dir %s)\n",
+               &iova, master, (prot == IOMMU_FAULT_WRITE) ? "wr" : "rd");
+
+       if (iommu->domain)
+               report_iommu_fault(iommu->domain, iommu->dev, iova, prot);
+       else
+               dev_err(iommu->dev, "Page fault while iommu not attached to any 
domain?\n");
+}
+
+static phys_addr_t sun50i_iommu_handle_pt_irq(struct sun50i_iommu *iommu,
+                                             unsigned addr_reg,
+                                             unsigned blame_reg)
+{
+       phys_addr_t iova;
+       unsigned master;
+       u32 blame;
+
+       assert_spin_locked(&iommu->iommu_lock);
+
+       iova = iommu_read(iommu, addr_reg);
+       blame = iommu_read(iommu, blame_reg);
+       master = ilog2(blame & IOMMU_INT_MASTER_MASK);
+
+       /*
+        * If the address is not in the page table, we can't get what
+        * operation triggered the fault. Assume it's a read
+        * operation.
+        */
+       sun50i_iommu_report_fault(iommu, master, iova, IOMMU_FAULT_READ);
+
+       return iova;
+}
+
+static phys_addr_t sun50i_iommu_handle_perm_irq(struct sun50i_iommu *iommu)
+{
+       enum sun50i_iommu_aci aci;
+       phys_addr_t iova;
+       unsigned master;
+       unsigned dir;
+       u32 blame;
+
+       assert_spin_locked(&iommu->iommu_lock);
+
+       blame = iommu_read(iommu, IOMMU_INT_STA_REG);
+       master = ilog2(blame & IOMMU_INT_MASTER_MASK);
+       iova = iommu_read(iommu, IOMMU_INT_ERR_ADDR_REG(master));
+       aci = sun50i_get_pte_aci(iommu_read(iommu,
+                                           IOMMU_INT_ERR_DATA_REG(master)));
+
+       switch (aci) {
+               /*
+                * If we are in the read-only domain, then it means we
+                * tried to write.
+                */
+       case SUN50I_IOMMU_ACI_RD:
+               dir = IOMMU_FAULT_WRITE;
+               break;
+
+               /*
+                * If we are in the write-only domain, then it means
+                * we tried to read.
+                */
+       case SUN50I_IOMMU_ACI_WR:
+
+               /*
+                * If we are in the domain without any permission, we
+                * can't really tell. Let's default to a read
+                * operation.
+                */
+       case SUN50I_IOMMU_ACI_NONE:
+
+               /* WTF? */
+       case SUN50I_IOMMU_ACI_RD_WR:
+       default:
+               dir = IOMMU_FAULT_READ;
+               break;
+       }
+
+       /*
+        * If the address is not in the page table, we can't get what
+        * operation triggered the fault. Assume it's a read
+        * operation.
+        */
+       sun50i_iommu_report_fault(iommu, master, iova, dir);
+
+       return iova;
+}
+
+static irqreturn_t sun50i_iommu_irq(int irq, void *dev_id)
+{
+       struct sun50i_iommu *iommu = dev_id;
+       phys_addr_t iova;
+       u32 status;
+
+       spin_lock(&iommu->iommu_lock);
+
+       status = iommu_read(iommu, IOMMU_INT_STA_REG);
+       if (!(status & IOMMU_INT_MASK)) {
+               spin_unlock(&iommu->iommu_lock);
+               return IRQ_NONE;
+       }
+
+       if (status & IOMMU_INT_INVALID_L2PG)
+               iova = sun50i_iommu_handle_pt_irq(iommu,
+                                                 IOMMU_INT_ERR_ADDR_L2_REG,
+                                                 IOMMU_L2PG_INT_REG);
+       else if (status & IOMMU_INT_INVALID_L1PG)
+               iova = sun50i_iommu_handle_pt_irq(iommu,
+                                                 IOMMU_INT_ERR_ADDR_L1_REG,
+                                                 IOMMU_L1PG_INT_REG);
+       else
+               iova = sun50i_iommu_handle_perm_irq(iommu);
+
+       sun50i_iommu_tlb_invalidate(iommu, iova);
+       sun50i_iommu_ptw_invalidate(iommu, iova);
+
+       iommu_write(iommu, IOMMU_INT_CLR_REG, status);
+
+       iommu_write(iommu, IOMMU_RESET_REG, ~status);
+       iommu_write(iommu, IOMMU_RESET_REG, status);
+
+       spin_unlock(&iommu->iommu_lock);
+
+       return IRQ_HANDLED;
+}
+
+static int sun50i_iommu_probe(struct platform_device *pdev)
+{
+       struct sun50i_iommu *iommu;
+       int ret, irq;
+
+       iommu = devm_kzalloc(&pdev->dev, sizeof(*iommu), GFP_KERNEL);
+       if (!iommu)
+               return -ENOMEM;
+       spin_lock_init(&iommu->iommu_lock);
+       platform_set_drvdata(pdev, iommu);
+       iommu->dev = &pdev->dev;
+
+       iommu->pt_pool = kmem_cache_create(dev_name(&pdev->dev),
+                                          PT_SIZE, PT_SIZE,
+                                          SLAB_HWCACHE_ALIGN,
+                                          NULL);
+       if (!iommu->pt_pool)
+               return -ENOMEM;
+
+       iommu->group = iommu_group_alloc();
+       if (IS_ERR(iommu->group)) {
+               ret = PTR_ERR(iommu->group);
+               goto err_free_cache;
+       }
+
+       iommu->base = devm_platform_ioremap_resource(pdev, 0);
+       if (!iommu->base) {
+               ret = PTR_ERR(iommu->base);
+               goto err_free_group;
+       }
+
+       irq = platform_get_irq(pdev, 0);
+       if (irq < 0) {
+               ret = irq;
+               goto err_free_group;
+       }
+
+       iommu->clk = devm_clk_get(&pdev->dev, NULL);
+       if (IS_ERR(iommu->clk)) {
+               dev_err(&pdev->dev, "Couldn't get our clock.\n");
+               ret = PTR_ERR(iommu->clk);
+               goto err_free_group;
+       }
+
+       iommu->reset = devm_reset_control_get(&pdev->dev, NULL);
+       if (IS_ERR(iommu->reset)) {
+               dev_err(&pdev->dev, "Couldn't get our reset line.\n");
+               ret = PTR_ERR(iommu->reset);
+               goto err_free_group;
+       }
+
+       ret = iommu_device_sysfs_add(&iommu->iommu, &pdev->dev,
+                                    NULL, dev_name(&pdev->dev));
+       if (ret)
+               goto err_free_group;
+
+       iommu_device_set_ops(&iommu->iommu, &sun50i_iommu_ops);
+       iommu_device_set_fwnode(&iommu->iommu, &pdev->dev.of_node->fwnode);
+
+       ret = iommu_device_register(&iommu->iommu);
+       if (ret)
+               goto err_remove_sysfs;
+
+       ret = devm_request_irq(&pdev->dev, irq, sun50i_iommu_irq, 0,
+                              dev_name(&pdev->dev), iommu);
+       if (ret < 0)
+               goto err_unregister;
+
+       bus_set_iommu(&platform_bus_type, &sun50i_iommu_ops);
+
+       return 0;
+
+err_unregister:
+       iommu_device_unregister(&iommu->iommu);
+
+err_remove_sysfs:
+       iommu_device_sysfs_remove(&iommu->iommu);
+
+err_free_group:
+       iommu_group_put(iommu->group);
+
+err_free_cache:
+       kmem_cache_destroy(iommu->pt_pool);
+
+       return ret;
+}
+
+static const struct of_device_id sun50i_iommu_dt[] = {
+       { .compatible = "allwinner,sun50i-h6-iommu", },
+       { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, sun50i_iommu_dt);
+
+static struct platform_driver sun50i_iommu_driver = {
+       .driver         = {
+               .name                   = "sun50i-iommu",
+               .of_match_table         = sun50i_iommu_dt,
+               .suppress_bind_attrs    = true,
+       }
+};
+builtin_platform_driver_probe(sun50i_iommu_driver, sun50i_iommu_probe);
+
+MODULE_DESCRIPTION("Allwinner H6 IOMMU driver");
+MODULE_AUTHOR("Maxime Ripard <max...@cerno.tech>");
+MODULE_AUTHOR("zhuxianbin <zhuxian...@allwinnertech.com>");
+MODULE_LICENSE("Dual BSD/GPL");
-- 
git-series 0.9.1
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