Hi,

One question is inlined below:

From: Hiroshi Doyu hdoyu@nvidia.com Subject: [PATCH v2 1/2] [RFC] ARM: IOMMU: Tegra20: iommu_ops for GART driver Date: Thu, 15 Dec 2011 14:11:29 +0100 Message-ID: 1323954690-7000-2-git-send-email-hdoyu@nvidia.com

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 | 451 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 463 insertions(+), 0 deletions(-) create mode 100644 drivers/iommu/tegra-gart.c

....

+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;
  

+};

+static struct gart_device *gart_handle; /* unique for a system */

^^^^^^^^^^^ .....

+static int gart_iommu_domain_init(struct iommu_domain *domain) +{

•   domain->priv = gart_handle;
  

^^^^^^^^^^^^^^^^^^^^^^^^^^^

•   pr_debug("gart@%p\n", gart_handle);
  

•   return 0;
  

+}

In the above, the global pointer is used to pass gart_device to set it in dmain->priv. It works with a single gart_device, but not with multiple gart_devices. This is too bad, I know;). I guess that this can be solved with device tree info where a client device is set as a child of gart_device at device registration. Is this the right way from IOMMU API POV?

for (i = 0; i < ARRAY_SIZE(dmaapi_dummy_device); i++) { int err; struct platform_device *pdev = &dmaapi_dummy_device[i];

pdev->dev.platform_data = (void *)dummy_hwgrp_map[i]; pdev->dev.parent = &tegra_gart_device; ^^^^^^^^^^^^^^^^^^^ err = platform_device_register(pdev);