1 files changed, 371 insertions, 0 deletions
diff --git a/drivers/iommu/tegra-gart.c b/drivers/iommu/tegra-gart.c
new file mode 100644
index 000000000..e5ca3cf1a
--- /dev/null
+++ b/drivers/iommu/tegra-gart.c
@@ -0,0 +1,371 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * IOMMU API for Graphics Address Relocation Table on Tegra20
+ *
+ * Copyright (c) 2010-2012, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * Author: Hiroshi DOYU <hdoyu@nvidia.com>
+ */
+
+#define dev_fmt(fmt)	"gart: " fmt
+
+#include <linux/io.h>
+#include <linux/iommu.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/vmalloc.h>
+
+#include <soc/tegra/mc.h>
+
+#define GART_REG_BASE		0x24
+#define GART_CONFIG		(0x24 - GART_REG_BASE)
+#define GART_ENTRY_ADDR		(0x28 - GART_REG_BASE)
+#define GART_ENTRY_DATA		(0x2c - GART_REG_BASE)
+
+#define GART_ENTRY_PHYS_ADDR_VALID	BIT(31)
+
+#define GART_PAGE_SHIFT		12
+#define GART_PAGE_SIZE		(1 << GART_PAGE_SHIFT)
+#define GART_PAGE_MASK		GENMASK(30, GART_PAGE_SHIFT)
+
+/* bitmap of the page sizes currently supported */
+#define GART_IOMMU_PGSIZES	(GART_PAGE_SIZE)
+
+struct gart_device {
+	void __iomem		*regs;
+	u32			*savedata;
+	unsigned long		iovmm_base;	/* offset to vmm_area start */
+	unsigned long		iovmm_end;	/* offset to vmm_area end */
+	spinlock_t		pte_lock;	/* for pagetable */
+	spinlock_t		dom_lock;	/* for active domain */
+	unsigned int		active_devices;	/* number of active devices */
+	struct iommu_domain	*active_domain;	/* current active domain */
+	struct iommu_device	iommu;		/* IOMMU Core handle */
+	struct device		*dev;
+};
+
+static struct gart_device *gart_handle; /* unique for a system */
+
+static bool gart_debug;
+
+/*
+ * Any interaction between any block on PPSB and a block on APB or AHB
+ * must have these read-back to ensure the APB/AHB bus transaction is
+ * complete before initiating activity on the PPSB block.
+ */
+#define FLUSH_GART_REGS(gart)	readl_relaxed((gart)->regs + GART_CONFIG)
+
+#define for_each_gart_pte(gart, iova)					\
+	for (iova = gart->iovmm_base;					\
+	     iova < gart->iovmm_end;					\
+	     iova += GART_PAGE_SIZE)
+
+static inline void gart_set_pte(struct gart_device *gart,
+				unsigned long iova, unsigned long pte)
+{
+	writel_relaxed(iova, gart->regs + GART_ENTRY_ADDR);
+	writel_relaxed(pte, gart->regs + GART_ENTRY_DATA);
+}
+
+static inline unsigned long gart_read_pte(struct gart_device *gart,
+					  unsigned long iova)
+{
+	unsigned long pte;
+
+	writel_relaxed(iova, gart->regs + GART_ENTRY_ADDR);
+	pte = readl_relaxed(gart->regs + GART_ENTRY_DATA);
+
+	return pte;
+}
+
+static void do_gart_setup(struct gart_device *gart, const u32 *data)
+{
+	unsigned long iova;
+
+	for_each_gart_pte(gart, iova)
+		gart_set_pte(gart, iova, data ? *(data++) : 0);
+
+	writel_relaxed(1, gart->regs + GART_CONFIG);
+	FLUSH_GART_REGS(gart);
+}
+
+static inline bool gart_iova_range_invalid(struct gart_device *gart,
+					   unsigned long iova, size_t bytes)
+{
+	return unlikely(iova < gart->iovmm_base || bytes != GART_PAGE_SIZE ||
+			iova + bytes > gart->iovmm_end);
+}
+
+static inline bool gart_pte_valid(struct gart_device *gart, unsigned long iova)
+{
+	return !!(gart_read_pte(gart, iova) & GART_ENTRY_PHYS_ADDR_VALID);
+}
+
+static int gart_iommu_attach_dev(struct iommu_domain *domain,
+				 struct device *dev)
+{
+	struct gart_device *gart = gart_handle;
+	int ret = 0;
+
+	spin_lock(&gart->dom_lock);
+
+	if (gart->active_domain && gart->active_domain != domain) {
+		ret = -EBUSY;
+	} else if (dev_iommu_priv_get(dev) != domain) {
+		dev_iommu_priv_set(dev, domain);
+		gart->active_domain = domain;
+		gart->active_devices++;
+	}
+
+	spin_unlock(&gart->dom_lock);
+
+	return ret;
+}
+
+static void gart_iommu_detach_dev(struct iommu_domain *domain,
+				  struct device *dev)
+{
+	struct gart_device *gart = gart_handle;
+
+	spin_lock(&gart->dom_lock);
+
+	if (dev_iommu_priv_get(dev) == domain) {
+		dev_iommu_priv_set(dev, NULL);
+
+		if (--gart->active_devices == 0)
+			gart->active_domain = NULL;
+	}
+
+	spin_unlock(&gart->dom_lock);
+}
+
+static struct iommu_domain *gart_iommu_domain_alloc(unsigned type)
+{
+	struct iommu_domain *domain;
+
+	if (type != IOMMU_DOMAIN_UNMANAGED)
+		return NULL;
+
+	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
+	if (domain) {
+		domain->geometry.aperture_start = gart_handle->iovmm_base;
+		domain->geometry.aperture_end = gart_handle->iovmm_end - 1;
+		domain->geometry.force_aperture = true;
+	}
+
+	return domain;
+}
+
+static void gart_iommu_domain_free(struct iommu_domain *domain)
+{
+	WARN_ON(gart_handle->active_domain == domain);
+	kfree(domain);
+}
+
+static inline int __gart_iommu_map(struct gart_device *gart, unsigned long iova,
+				   unsigned long pa)
+{
+	if (unlikely(gart_debug && gart_pte_valid(gart, iova))) {
+		dev_err(gart->dev, "Page entry is in-use\n");
+		return -EINVAL;
+	}
+
+	gart_set_pte(gart, iova, GART_ENTRY_PHYS_ADDR_VALID | pa);
+
+	return 0;
+}
+
+static int gart_iommu_map(struct iommu_domain *domain, unsigned long iova,
+			  phys_addr_t pa, size_t bytes, int prot, gfp_t gfp)
+{
+	struct gart_device *gart = gart_handle;
+	int ret;
+
+	if (gart_iova_range_invalid(gart, iova, bytes))
+		return -EINVAL;
+
+	spin_lock(&gart->pte_lock);
+	ret = __gart_iommu_map(gart, iova, (unsigned long)pa);
+	spin_unlock(&gart->pte_lock);
+
+	return ret;
+}
+
+static inline int __gart_iommu_unmap(struct gart_device *gart,
+				     unsigned long iova)
+{
+	if (unlikely(gart_debug && !gart_pte_valid(gart, iova))) {
+		dev_err(gart->dev, "Page entry is invalid\n");
+		return -EINVAL;
+	}
+
+	gart_set_pte(gart, iova, 0);
+
+	return 0;
+}
+
+static size_t gart_iommu_unmap(struct iommu_domain *domain, unsigned long iova,
+			       size_t bytes, struct iommu_iotlb_gather *gather)
+{
+	struct gart_device *gart = gart_handle;
+	int err;
+
+	if (gart_iova_range_invalid(gart, iova, bytes))
+		return 0;
+
+	spin_lock(&gart->pte_lock);
+	err = __gart_iommu_unmap(gart, iova);
+	spin_unlock(&gart->pte_lock);
+
+	return err ? 0 : bytes;
+}
+
+static phys_addr_t gart_iommu_iova_to_phys(struct iommu_domain *domain,
+					   dma_addr_t iova)
+{
+	struct gart_device *gart = gart_handle;
+	unsigned long pte;
+
+	if (gart_iova_range_invalid(gart, iova, GART_PAGE_SIZE))
+		return -EINVAL;
+
+	spin_lock(&gart->pte_lock);
+	pte = gart_read_pte(gart, iova);
+	spin_unlock(&gart->pte_lock);
+
+	return pte & GART_PAGE_MASK;
+}
+
+static struct iommu_device *gart_iommu_probe_device(struct device *dev)
+{
+	if (!dev_iommu_fwspec_get(dev))
+		return ERR_PTR(-ENODEV);
+
+	return &gart_handle->iommu;
+}
+
+static int gart_iommu_of_xlate(struct device *dev,
+			       struct of_phandle_args *args)
+{
+	return 0;
+}
+
+static void gart_iommu_sync_map(struct iommu_domain *domain, unsigned long iova,
+				size_t size)
+{
+	FLUSH_GART_REGS(gart_handle);
+}
+
+static void gart_iommu_sync(struct iommu_domain *domain,
+			    struct iommu_iotlb_gather *gather)
+{
+	size_t length = gather->end - gather->start + 1;
+
+	gart_iommu_sync_map(domain, gather->start, length);
+}
+
+static const struct iommu_ops gart_iommu_ops = {
+	.domain_alloc	= gart_iommu_domain_alloc,
+	.probe_device	= gart_iommu_probe_device,
+	.device_group	= generic_device_group,
+	.pgsize_bitmap	= GART_IOMMU_PGSIZES,
+	.of_xlate	= gart_iommu_of_xlate,
+	.default_domain_ops = &(const struct iommu_domain_ops) {
+		.attach_dev	= gart_iommu_attach_dev,
+		.detach_dev	= gart_iommu_detach_dev,
+		.map		= gart_iommu_map,
+		.unmap		= gart_iommu_unmap,
+		.iova_to_phys	= gart_iommu_iova_to_phys,
+		.iotlb_sync_map	= gart_iommu_sync_map,
+		.iotlb_sync	= gart_iommu_sync,
+		.free		= gart_iommu_domain_free,
+	}
+};
+
+int tegra_gart_suspend(struct gart_device *gart)
+{
+	u32 *data = gart->savedata;
+	unsigned long iova;
+
+	/*
+	 * All GART users shall be suspended at this point. Disable
+	 * address translation to trap all GART accesses as invalid
+	 * memory accesses.
+	 */
+	writel_relaxed(0, gart->regs + GART_CONFIG);
+	FLUSH_GART_REGS(gart);
+
+	for_each_gart_pte(gart, iova)
+		*(data++) = gart_read_pte(gart, iova);
+
+	return 0;
+}
+
+int tegra_gart_resume(struct gart_device *gart)
+{
+	do_gart_setup(gart, gart->savedata);
+
+	return 0;
+}
+
+struct gart_device *tegra_gart_probe(struct device *dev, struct tegra_mc *mc)
+{
+	struct gart_device *gart;
+	struct resource *res;
+	int err;
+
+	BUILD_BUG_ON(PAGE_SHIFT != GART_PAGE_SHIFT);
+
+	/* the GART memory aperture is required */
+	res = platform_get_resource(to_platform_device(dev), IORESOURCE_MEM, 1);
+	if (!res) {
+		dev_err(dev, "Memory aperture resource unavailable\n");
+		return ERR_PTR(-ENXIO);
+	}
+
+	gart = kzalloc(sizeof(*gart), GFP_KERNEL);
+	if (!gart)
+		return ERR_PTR(-ENOMEM);
+
+	gart_handle = gart;
+
+	gart->dev = dev;
+	gart->regs = mc->regs + GART_REG_BASE;
+	gart->iovmm_base = res->start;
+	gart->iovmm_end = res->end + 1;
+	spin_lock_init(&gart->pte_lock);
+	spin_lock_init(&gart->dom_lock);
+
+	do_gart_setup(gart, NULL);
+
+	err = iommu_device_sysfs_add(&gart->iommu, dev, NULL, "gart");
+	if (err)
+		goto free_gart;
+
+	err = iommu_device_register(&gart->iommu, &gart_iommu_ops, dev);
+	if (err)
+		goto remove_sysfs;
+
+	gart->savedata = vmalloc(resource_size(res) / GART_PAGE_SIZE *
+				 sizeof(u32));
+	if (!gart->savedata) {
+		err = -ENOMEM;
+		goto unregister_iommu;
+	}
+
+	return gart;
+
+unregister_iommu:
+	iommu_device_unregister(&gart->iommu);
+remove_sysfs:
+	iommu_device_sysfs_remove(&gart->iommu);
+free_gart:
+	kfree(gart);
+
+	return ERR_PTR(err);
+}
+
+module_param(gart_debug, bool, 0644);
+MODULE_PARM_DESC(gart_debug, "Enable GART debugging");