[PATCH v2 4/8] iommu/mediatek: Merge 2 M4U HWs into one iommu domain

From: Yong Wu
Date: Mon Aug 21 2017 - 07:01:21 EST


In theory, If there are 2 M4U HWs, there should be 2 IOMMU domains.
But one IOMMU domain(4GB iova range) is enough for us currently,
It's unnecessary to maintain 2 pagetables.

Besides, This patch can simplify our consumer code largely. They don't
need map a iova range from one domain into another, They can share the
iova address easily.

Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
---
drivers/iommu/mtk_iommu.c | 92 ++++++++++++++++++++++++++++++++++-------------
drivers/iommu/mtk_iommu.h | 2 ++
2 files changed, 70 insertions(+), 24 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index df23e02..1503dfa 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -114,6 +114,27 @@ struct mtk_iommu_domain {

static struct iommu_ops mtk_iommu_ops;

+static LIST_HEAD(m4ulist); /* List all the M4U HWs */
+
+#define for_each_m4u(data) list_for_each_entry(data, &m4ulist, list)
+
+/*
+ * There may be 1 or 2 M4U HWs, But we always expect they are in the same domain
+ * for the performance.
+ *
+ * Here always return the mtk_iommu_data of the first probed M4U where the
+ * iommu domain information is recorded.
+ */
+static struct mtk_iommu_data *mtk_iommu_get_m4u_data(void)
+{
+ struct mtk_iommu_data *data;
+
+ for_each_m4u(data)
+ return data;
+
+ return NULL;
+}
+
static struct mtk_iommu_domain *to_mtk_domain(struct iommu_domain *dom)
{
return container_of(dom, struct mtk_iommu_domain, domain);
@@ -123,9 +144,12 @@ static void mtk_iommu_tlb_flush_all(void *cookie)
{
struct mtk_iommu_data *data = cookie;

- 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 */
+ for_each_m4u(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_add_flush_nosync(unsigned long iova, size_t size,
@@ -134,12 +158,17 @@ static void mtk_iommu_tlb_add_flush_nosync(unsigned long iova, size_t size,
{
struct mtk_iommu_data *data = cookie;

- writel_relaxed(F_INVLD_EN1 | F_INVLD_EN0, data->base + REG_MMU_INV_SEL);
+ for_each_m4u(data) {
+ writel_relaxed(F_INVLD_EN1 | F_INVLD_EN0,
+ data->base + REG_MMU_INV_SEL);

- writel_relaxed(iova, data->base + REG_MMU_INVLD_START_A);
- writel_relaxed(iova + size - 1, data->base + REG_MMU_INVLD_END_A);
- writel_relaxed(F_MMU_INV_RANGE, data->base + REG_MMU_INVALIDATE);
- data->tlb_flush_active = true;
+ writel_relaxed(iova, data->base + REG_MMU_INVLD_START_A);
+ writel_relaxed(iova + size - 1,
+ data->base + REG_MMU_INVLD_END_A);
+ writel_relaxed(F_MMU_INV_RANGE,
+ data->base + REG_MMU_INVALIDATE);
+ data->tlb_flush_active = true;
+ }
}

static void mtk_iommu_tlb_sync(void *cookie)
@@ -148,20 +177,22 @@ static void mtk_iommu_tlb_sync(void *cookie)
int ret;
u32 tmp;

- /* Avoid timing out if there's nothing to wait for */
- if (!data->tlb_flush_active)
- return;
+ for_each_m4u(data) {
+ /* Avoid timing out if there's nothing to wait for */
+ if (!data->tlb_flush_active)
+ return;

- 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(cookie);
+ 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(cookie);
+ }
+ /* Clear the CPE status */
+ writel_relaxed(0, data->base + REG_MMU_CPE_DONE);
+ data->tlb_flush_active = false;
}
- /* Clear the CPE status */
- writel_relaxed(0, data->base + REG_MMU_CPE_DONE);
- data->tlb_flush_active = false;
}

static const struct iommu_gather_ops mtk_iommu_gather_ops = {
@@ -298,10 +329,11 @@ 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;
+ struct mtk_iommu_data *curdata = dev->iommu_fwspec->iommu_priv;
+ struct mtk_iommu_data *data = mtk_iommu_get_m4u_data();
int ret;

- if (!data)
+ if (!data || !curdata)
return -ENODEV;

if (!data->m4u_dom) {
@@ -313,7 +345,17 @@ static int mtk_iommu_attach_device(struct iommu_domain *domain,
}
}

- mtk_iommu_config(data, dev, true);
+ /*
+ * Update the pgtable base address register of another M4U HW with the
+ * existed pgtable if there are more than one M4U HW.
+ */
+ if (!curdata->m4u_dom) {
+ curdata->m4u_dom = data->m4u_dom;
+ writel(data->m4u_dom->cfg.arm_v7s_cfg.ttbr[0],
+ curdata->base + REG_MMU_PT_BASE_ADDR);
+ }
+
+ mtk_iommu_config(curdata, dev, true);
return 0;
}

@@ -405,7 +447,7 @@ static void mtk_iommu_remove_device(struct device *dev)

static struct iommu_group *mtk_iommu_device_group(struct device *dev)
{
- struct mtk_iommu_data *data = dev->iommu_fwspec->iommu_priv;
+ struct mtk_iommu_data *data = mtk_iommu_get_m4u_data();

if (!data)
return ERR_PTR(-ENODEV);
@@ -604,6 +646,8 @@ static int mtk_iommu_probe(struct platform_device *pdev)
if (ret)
return ret;

+ list_add_tail(&data->list, &m4ulist);
+
if (!iommu_present(&platform_bus_type))
bus_set_iommu(&platform_bus_type, &mtk_iommu_ops);

diff --git a/drivers/iommu/mtk_iommu.h b/drivers/iommu/mtk_iommu.h
index 462e593..b4451a1 100644
--- a/drivers/iommu/mtk_iommu.h
+++ b/drivers/iommu/mtk_iommu.h
@@ -57,6 +57,8 @@ struct mtk_iommu_data {

struct iommu_device iommu;
enum mtk_iommu_plat m4u_plat;
+
+ struct list_head list;
};

static inline int compare_of(struct device *dev, void *data)
--
1.9.1