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Subject[PATCH 1/2] ARM: IOMMU: Tegra20: Add iommu_ops for GART driver
Date
Tegra 20 IOMMU H/W, GART (Graphics Address Relocation Table). This
patch implements struct iommu_ops for GART for the upper IOMMU API.

This H/W module supports only single virtual address space(domain),
and manages a single level 1-to-1 mapping H/W translation page table.

Signed-off-by: Hiroshi DOYU <hdoyu@nvidia.com>
---
drivers/iommu/Kconfig | 11 +
drivers/iommu/Makefile | 1 +
drivers/iommu/tegra-gart.c | 436 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 448 insertions(+), 0 deletions(-)
create mode 100644 drivers/iommu/tegra-gart.c
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 6bea696..4562698 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -142,4 +142,15 @@ config OMAP_IOMMU_DEBUG

Say N unless you know you need this.

+config TEGRA_IOMMU_GART
+ bool "Tegra GART IOMMU Support"
+ depends on ARCH_TEGRA_2x_SOC
+ default y
+ select IOMMU_API
+ help
+ Enables support for remapping discontiguous physical memory
+ shared with the operating system into contiguous I/O virtual
+ space through the GART (Graphics Address Relocation Table)
+ hardware included on Tegra SoCs.
+
endif # IOMMU_SUPPORT
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index 0e36b49..3238a31 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_IRQ_REMAP) += intr_remapping.o
obj-$(CONFIG_OMAP_IOMMU) += omap-iommu.o
obj-$(CONFIG_OMAP_IOVMM) += omap-iovmm.o
obj-$(CONFIG_OMAP_IOMMU_DEBUG) += omap-iommu-debug.o
+obj-$(CONFIG_TEGRA_IOMMU_GART) += tegra-gart.o
diff --git a/drivers/iommu/tegra-gart.c b/drivers/iommu/tegra-gart.c
new file mode 100644
index 0000000..feaccd4
--- /dev/null
+++ b/drivers/iommu/tegra-gart.c
@@ -0,0 +1,436 @@
+/*
+ * IOMMU API for GART in Tegra20
+ *
+ * Copyright (c) 2010-2012, NVIDIA CORPORATION. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#define pr_fmt(fmt) "%s(): " fmt, __func__
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+#include <linux/list.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/iommu.h>
+
+#include <asm/cacheflush.h>
+
+/* bitmap of the page sizes currently supported */
+#define GART_IOMMU_PGSIZES (SZ_4K)
+
+#define GART_CONFIG 0x24
+#define GART_ENTRY_ADDR 0x28
+#define GART_ENTRY_DATA 0x2c
+#define GART_ENTRY_PHYS_ADDR_VALID (1 << 31)
+
+#define GART_PAGE_SHIFT 12
+#define GART_PAGE_SIZE (1 << GART_PAGE_SHIFT)
+#define GART_PAGE_MASK \
+ (~(GART_PAGE_SIZE - 1) & ~GART_ENTRY_PHYS_ADDR_VALID)
+
+struct gart_client {
+ struct device *dev;
+ struct list_head list;
+};
+
+struct gart_device {
+ void __iomem *regs;
+ u32 *savedata;
+ u32 page_count; /* total remappable size */
+ dma_addr_t iovmm_base; /* offset to apply to vmm_area */
+ spinlock_t pte_lock; /* for pagetable */
+ struct list_head client;
+ spinlock_t client_lock; /* for client list */
+ struct device *dev;
+};
+
+#define GART_PTE(_pfn) \
+ (GART_ENTRY_PHYS_ADDR_VALID | ((_pfn) << PAGE_SHIFT))
+
+/*
+ * 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) ((void)readl((gart)->regs + GART_CONFIG))
+
+#define for_each_gart_pte(gart, iova) \
+ for (iova = gart->iovmm_base; \
+ iova < gart->iovmm_base + GART_PAGE_SIZE * gart->page_count; \
+ iova += GART_PAGE_SIZE)
+
+static inline void gart_set_pte(struct gart_device *gart,
+ unsigned long offs, u32 pte)
+{
+ writel(offs, gart->regs + GART_ENTRY_ADDR);
+ writel(pte, gart->regs + GART_ENTRY_DATA);
+
+ dev_dbg(gart->dev, "%s %08lx:%08x\n",
+ pte ? "map" : "unmap", offs, pte & GART_PAGE_MASK);
+}
+
+static inline unsigned long gart_read_pte(struct gart_device *gart,
+ unsigned long offs)
+{
+ unsigned long pte;
+
+ writel(offs, gart->regs + GART_ENTRY_ADDR);
+ pte = readl(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(1, gart->regs + GART_CONFIG);
+ FLUSH_GART_REGS(gart);
+}
+
+#ifdef DEBUG
+static void gart_dump_table(struct gart_device *gart)
+{
+ unsigned long iova;
+ unsigned long flags;
+
+ spin_lock_irqsave(&gart->pte_lock, flags);
+ for_each_gart_pte(gart, iova) {
+ unsigned long pte;
+
+ pte = gart_read_pte(gart, iova);
+
+ dev_dbg(gart->dev, "%s %08lx:%08lx\n",
+ (GART_ENTRY_PHYS_ADDR_VALID & pte) ? "v" : " ",
+ iova, pte & GART_PAGE_MASK);
+ }
+ spin_unlock_irqrestore(&gart->pte_lock, flags);
+}
+#else
+static inline void gart_dump_table(struct gart_device *gart)
+{
+}
+#endif
+
+static inline bool gart_iova_range_valid(struct gart_device *gart,
+ unsigned long iova, size_t bytes)
+{
+ unsigned long iova_start, iova_end, gart_start, gart_end;
+
+ iova_start = iova;
+ iova_end = iova_start + bytes - 1;
+ gart_start = gart->iovmm_base;
+ gart_end = gart_start + gart->page_count * GART_PAGE_SIZE - 1;
+
+ if (iova_start < gart_start)
+ return false;
+ if (iova_end > gart_end)
+ return false;
+ return true;
+}
+
+static int gart_iommu_domain_init(struct iommu_domain *domain)
+{
+ return 0;
+}
+
+static void gart_iommu_domain_destroy(struct iommu_domain *domain)
+{
+ struct gart_device *gart = domain->priv;
+
+ spin_lock(&gart->client_lock);
+ if (!list_empty(&gart->client)) {
+ struct gart_client *c;
+
+ list_for_each_entry(c, &gart->client, list)
+ dev_err(gart->dev,
+ "%s is still attached\n", dev_name(c->dev));
+ }
+ spin_unlock(&gart->client_lock);
+ domain->priv = NULL;
+}
+
+static int gart_iommu_attach_dev(struct iommu_domain *domain,
+ struct device *dev)
+{
+ struct gart_device *gart;
+ struct gart_client *client, *c;
+ int err = 0;
+
+ gart = dev_get_drvdata(dev->parent);
+ if (!gart)
+ return -EINVAL;
+ domain->priv = gart;
+ client = devm_kzalloc(dev, sizeof(*c), GFP_KERNEL);
+ if (!client)
+ return -ENOMEM;
+ client->dev = dev;
+
+ spin_lock(&gart->client_lock);
+ list_for_each_entry(c, &gart->client, list) {
+ if (c->dev == dev) {
+ dev_err(gart->dev,
+ "%s is already attached\n", dev_name(dev));
+ err = -EINVAL;
+ goto fail;
+ }
+ }
+ list_add(&client->list, &gart->client);
+ spin_unlock(&gart->client_lock);
+ dev_dbg(gart->dev, "Attached %s\n", dev_name(dev));
+ return 0;
+
+fail:
+ devm_kfree(dev, client);
+ spin_unlock(&gart->client_lock);
+ return err;
+}
+
+static void gart_iommu_detach_dev(struct iommu_domain *domain,
+ struct device *dev)
+{
+ struct gart_device *gart = domain->priv;
+ struct gart_client *c;
+
+ spin_lock(&gart->client_lock);
+
+ list_for_each_entry(c, &gart->client, list) {
+ if (c->dev == dev) {
+ list_del(&c->list);
+ devm_kfree(dev, c);
+ dev_dbg(gart->dev, "Detached %s\n", dev_name(dev));
+ goto out;
+ }
+ }
+ dev_err(gart->dev, "Couldn't find\n");
+out:
+ spin_unlock(&gart->client_lock);
+}
+
+static int gart_iommu_map(struct iommu_domain *domain, unsigned long iova,
+ phys_addr_t pa, size_t bytes, int prot)
+{
+ struct gart_device *gart = domain->priv;
+ unsigned long flags;
+ unsigned long pfn;
+
+ if (!gart_iova_range_valid(gart, iova, bytes))
+ return -EINVAL;
+
+ spin_lock_irqsave(&gart->pte_lock, flags);
+ pfn = __phys_to_pfn(pa);
+ if (!pfn_valid(pfn)) {
+ dev_err(gart->dev, "Invalid page: %08x\n", pa);
+ spin_unlock(&gart->pte_lock);
+ return -EINVAL;
+ }
+ gart_set_pte(gart, iova, GART_PTE(pfn));
+ FLUSH_GART_REGS(gart);
+ spin_unlock_irqrestore(&gart->pte_lock, flags);
+ return 0;
+}
+
+static size_t gart_iommu_unmap(struct iommu_domain *domain, unsigned long iova,
+ size_t bytes)
+{
+ struct gart_device *gart = domain->priv;
+ unsigned long flags;
+
+ if (!gart_iova_range_valid(gart, iova, bytes))
+ return -EINVAL;
+
+ spin_lock_irqsave(&gart->pte_lock, flags);
+ gart_set_pte(gart, iova, 0);
+ FLUSH_GART_REGS(gart);
+ spin_unlock_irqrestore(&gart->pte_lock, flags);
+ return 0;
+}
+
+static phys_addr_t gart_iommu_iova_to_phys(struct iommu_domain *domain,
+ unsigned long iova)
+{
+ struct gart_device *gart = domain->priv;
+ unsigned long pte;
+ phys_addr_t pa;
+ unsigned long flags;
+
+ if (!gart_iova_range_valid(gart, iova, 0))
+ return -EINVAL;
+
+ spin_lock_irqsave(&gart->pte_lock, flags);
+ pte = gart_read_pte(gart, iova);
+ spin_unlock_irqrestore(&gart->pte_lock, flags);
+
+ pa = (pte & GART_PAGE_MASK);
+ if (!pfn_valid(__phys_to_pfn(pa))) {
+ dev_err(gart->dev, "No entry for %08lx:%08x\n", iova, pa);
+ gart_dump_table(gart);
+ return -EINVAL;
+ }
+ return pa;
+}
+
+static int gart_iommu_domain_has_cap(struct iommu_domain *domain,
+ unsigned long cap)
+{
+ return 0;
+}
+
+static struct iommu_ops gart_iommu_ops = {
+ .domain_init = gart_iommu_domain_init,
+ .domain_destroy = gart_iommu_domain_destroy,
+ .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,
+ .domain_has_cap = gart_iommu_domain_has_cap,
+ .pgsize_bitmap = GART_IOMMU_PGSIZES,
+};
+
+static int tegra_gart_suspend(struct device *dev)
+{
+ struct gart_device *gart = dev_get_drvdata(dev);
+ unsigned long iova;
+ u32 *data = gart->savedata;
+ unsigned long flags;
+
+ spin_lock_irqsave(&gart->pte_lock, flags);
+ for_each_gart_pte(gart, iova)
+ *(data++) = gart_read_pte(gart, iova);
+ spin_unlock_irqrestore(&gart->pte_lock, flags);
+ return 0;
+}
+
+static int tegra_gart_resume(struct device *dev)
+{
+ struct gart_device *gart = dev_get_drvdata(dev);
+ unsigned long flags;
+
+ spin_lock_irqsave(&gart->pte_lock, flags);
+ do_gart_setup(gart, gart->savedata);
+ spin_unlock_irqrestore(&gart->pte_lock, flags);
+ return 0;
+}
+
+static int tegra_gart_probe(struct platform_device *pdev)
+{
+ struct gart_device *gart;
+ struct resource *res, *res_remap;
+ void __iomem *gart_regs;
+ int err;
+ struct device *dev = &pdev->dev;
+
+ BUILD_BUG_ON(PAGE_SHIFT != GART_PAGE_SHIFT);
+
+ /* the GART memory aperture is required */
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ res_remap = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+ if (!res || !res_remap) {
+ dev_err(dev, "GART memory aperture expected\n");
+ return -ENXIO;
+ }
+
+ gart = devm_kzalloc(dev, sizeof(*gart), GFP_KERNEL);
+ if (!gart) {
+ dev_err(dev, "failed to allocate gart_device\n");
+ return -ENOMEM;
+ }
+
+ gart_regs = devm_ioremap(dev, res->start, resource_size(res));
+ if (!gart_regs) {
+ dev_err(dev, "failed to remap GART registers\n");
+ err = -ENXIO;
+ goto fail;
+ }
+
+ gart->dev = &pdev->dev;
+ spin_lock_init(&gart->pte_lock);
+ spin_lock_init(&gart->client_lock);
+ INIT_LIST_HEAD(&gart->client);
+ gart->regs = gart_regs;
+ gart->iovmm_base = (dma_addr_t)res_remap->start;
+ gart->page_count = (resource_size(res_remap) >> GART_PAGE_SHIFT);
+
+ gart->savedata = vmalloc(sizeof(u32) * gart->page_count);
+ if (!gart->savedata) {
+ dev_err(dev, "failed to allocate context save area\n");
+ err = -ENOMEM;
+ goto fail;
+ }
+
+ platform_set_drvdata(pdev, gart);
+ do_gart_setup(gart, NULL);
+ return 0;
+
+fail:
+ if (gart_regs)
+ devm_iounmap(dev, gart_regs);
+ if (gart && gart->savedata)
+ vfree(gart->savedata);
+ devm_kfree(dev, gart);
+ return err;
+}
+
+static int tegra_gart_remove(struct platform_device *pdev)
+{
+ struct gart_device *gart = platform_get_drvdata(pdev);
+ struct device *dev = gart->dev;
+
+ writel(0, gart->regs + GART_CONFIG);
+ if (gart->savedata)
+ vfree(gart->savedata);
+ if (gart->regs)
+ devm_iounmap(dev, gart->regs);
+ devm_kfree(dev, gart);
+ return 0;
+}
+
+const struct dev_pm_ops tegra_gart_pm_ops = {
+ .suspend = tegra_gart_suspend,
+ .resume = tegra_gart_resume,
+};
+
+static struct platform_driver tegra_gart_driver = {
+ .probe = tegra_gart_probe,
+ .remove = tegra_gart_remove,
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "tegra-gart",
+ .pm = &tegra_gart_pm_ops,
+ },
+};
+
+static int __devinit tegra_gart_init(void)
+{
+ bus_set_iommu(&platform_bus_type, &gart_iommu_ops);
+ return platform_driver_register(&tegra_gart_driver);
+}
+
+static void __exit tegra_gart_exit(void)
+{
+ platform_driver_unregister(&tegra_gart_driver);
+}
+
+subsys_initcall(tegra_gart_init);
+module_exit(tegra_gart_exit);
--
1.7.5.4


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