iommu/rockchip: Add missing set_platform_dma_ops callback

Similar to exynos, we need a set_platform_dma_ops() callback for proper
operation on ARM 32 bit after recent changes in the IOMMU framework
(detach ops removal). But also the use of a NULL domain is confusing.

Rework the code to add support for IOMMU_DOMAIN_IDENTITY and a singleton
rk_identity_domain which is assigned to domain when using an identity
mapping rather than "detaching". This makes the code easier to reason about.

Signed-off-by: Steven Price <steven.price@arm.com>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20230331095154.2671129-1-steven.price@arm.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index f30db22ea5d7a72906c5a5f41ab233df791e9ce2..ea5a3088bb7e8a566ab9285d644009eb2bcd1d6a 100644 (file)
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c
@@ -124,6 +124,7 @@ struct rk_iommudata {
 
 static struct device *dma_dev;
 static const struct rk_iommu_ops *rk_ops;
+static struct iommu_domain rk_identity_domain;
 
 static inline void rk_table_flush(struct rk_iommu_domain *dom, dma_addr_t dma,
                                  unsigned int count)
@@ -646,7 +647,7 @@ static irqreturn_t rk_iommu_irq(int irq, void *dev_id)
                         * Ignore the return code, though, since we always zap cache
                         * and clear the page fault anyway.
                         */
-                       if (iommu->domain)
+                       if (iommu->domain != &rk_identity_domain)
                                report_iommu_fault(iommu->domain, iommu->dev, iova,
                                                   flags);
                        else
@@ -980,26 +981,27 @@ out_disable_clocks:
        return ret;
 }
 
-static void rk_iommu_detach_device(struct iommu_domain *domain,
-                                  struct device *dev)
+static int rk_iommu_identity_attach(struct iommu_domain *identity_domain,
+                                   struct device *dev)
 {
        struct rk_iommu *iommu;
-       struct rk_iommu_domain *rk_domain = to_rk_domain(domain);
+       struct rk_iommu_domain *rk_domain;
        unsigned long flags;
        int ret;
 
        /* Allow 'virtual devices' (eg drm) to detach from domain */
        iommu = rk_iommu_from_dev(dev);
        if (!iommu)
-               return;
+               return -ENODEV;
+
+       rk_domain = to_rk_domain(iommu->domain);
 
        dev_dbg(dev, "Detaching from iommu domain\n");
 
-       /* iommu already detached */
-       if (iommu->domain != domain)
-               return;
+       if (iommu->domain == identity_domain)
+               return 0;
 
-       iommu->domain = NULL;
+       iommu->domain = identity_domain;
 
        spin_lock_irqsave(&rk_domain->iommus_lock, flags);
        list_del_init(&iommu->node);
@@ -1011,8 +1013,31 @@ static void rk_iommu_detach_device(struct iommu_domain *domain,
                rk_iommu_disable(iommu);
                pm_runtime_put(iommu->dev);
        }
+
+       return 0;
 }
 
+static void rk_iommu_identity_free(struct iommu_domain *domain)
+{
+}
+
+static struct iommu_domain_ops rk_identity_ops = {
+       .attach_dev = rk_iommu_identity_attach,
+       .free = rk_iommu_identity_free,
+};
+
+static struct iommu_domain rk_identity_domain = {
+       .type = IOMMU_DOMAIN_IDENTITY,
+       .ops = &rk_identity_ops,
+};
+
+#ifdef CONFIG_ARM
+static void rk_iommu_set_platform_dma(struct device *dev)
+{
+       WARN_ON(rk_iommu_identity_attach(&rk_identity_domain, dev));
+}
+#endif
+
 static int rk_iommu_attach_device(struct iommu_domain *domain,
                struct device *dev)
 {
@@ -1035,8 +1060,9 @@ static int rk_iommu_attach_device(struct iommu_domain *domain,
        if (iommu->domain == domain)
                return 0;
 
-       if (iommu->domain)
-               rk_iommu_detach_device(iommu->domain, dev);
+       ret = rk_iommu_identity_attach(&rk_identity_domain, dev);
+       if (ret)
+               return ret;
 
        iommu->domain = domain;
 
@@ -1050,7 +1076,7 @@ static int rk_iommu_attach_device(struct iommu_domain *domain,
 
        ret = rk_iommu_enable(iommu);
        if (ret)
-               rk_iommu_detach_device(iommu->domain, dev);
+               WARN_ON(rk_iommu_identity_attach(&rk_identity_domain, dev));
 
        pm_runtime_put(iommu->dev);
 
@@ -1061,6 +1087,9 @@ static struct iommu_domain *rk_iommu_domain_alloc(unsigned type)
 {
        struct rk_iommu_domain *rk_domain;
 
+       if (type == IOMMU_DOMAIN_IDENTITY)
+               return &rk_identity_domain;
+
        if (type != IOMMU_DOMAIN_UNMANAGED && type != IOMMU_DOMAIN_DMA)
                return NULL;
 
@@ -1176,6 +1205,7 @@ static int rk_iommu_of_xlate(struct device *dev,
        iommu_dev = of_find_device_by_node(args->np);
 
        data->iommu = platform_get_drvdata(iommu_dev);
+       data->iommu->domain = &rk_identity_domain;
        dev_iommu_priv_set(dev, data);
 
        platform_device_put(iommu_dev);
@@ -1188,6 +1218,9 @@ static const struct iommu_ops rk_iommu_ops = {
        .probe_device = rk_iommu_probe_device,
        .release_device = rk_iommu_release_device,
        .device_group = rk_iommu_device_group,
+#ifdef CONFIG_ARM
+       .set_platform_dma_ops = rk_iommu_set_platform_dma,
+#endif
        .pgsize_bitmap = RK_IOMMU_PGSIZE_BITMAP,
        .of_xlate = rk_iommu_of_xlate,
        .default_domain_ops = &(const struct iommu_domain_ops) {
@@ -1343,7 +1376,7 @@ static int __maybe_unused rk_iommu_suspend(struct device *dev)
 {
        struct rk_iommu *iommu = dev_get_drvdata(dev);
 
-       if (!iommu->domain)
+       if (iommu->domain == &rk_identity_domain)
                return 0;
 
        rk_iommu_disable(iommu);
@@ -1354,7 +1387,7 @@ static int __maybe_unused rk_iommu_resume(struct device *dev)
 {
        struct rk_iommu *iommu = dev_get_drvdata(dev);
 
-       if (!iommu->domain)
+       if (iommu->domain == &rk_identity_domain)
                return 0;
 
        return rk_iommu_enable(iommu);