[PATCH 12/15] habanalabs: Allow accessing DRAM virtual addresses via debugfs

[Oded Gabbay]

From: Tomer Tayar <tta...@habana.ai>

The addr/data32 debugfs nodes currently permit the access to only physical
addresses of a device. This patch extends it and allows accessing also
device's DRAM virtual addresses.

Signed-off-by: Tomer Tayar <tta...@habana.ai>
Signed-off-by: Oded Gabbay <oded.gab...@gmail.com>
---
 drivers/misc/habanalabs/debugfs.c | 96 +++++++++++++++++++++++++++++--
 1 file changed, 91 insertions(+), 5 deletions(-)

diff --git a/drivers/misc/habanalabs/debugfs.c 
b/drivers/misc/habanalabs/debugfs.c
index 974a87789bd8..a4447699ff4e 100644
--- a/drivers/misc/habanalabs/debugfs.c
+++ b/drivers/misc/habanalabs/debugfs.c
@@ -505,22 +505,97 @@ static ssize_t mmu_write(struct file *file, const char 
__user *buf,
        return -EINVAL;
 }
 
+static int device_va_to_pa(struct hl_device *hdev, u64 virt_addr,
+                               u64 *phys_addr)
+{
+       struct hl_ctx *ctx = hdev->user_ctx;
+       u64 hop_addr, hop_pte_addr, hop_pte;
+       int rc = 0;
+
+       if (!ctx) {
+               dev_err(hdev->dev, "no ctx available\n");
+               return -EINVAL;
+       }
+
+       mutex_lock(&ctx->mmu_lock);
+
+       /* hop 0 */
+       hop_addr = get_hop0_addr(ctx);
+       hop_pte_addr = get_hop0_pte_addr(ctx, hop_addr, virt_addr);
+       hop_pte = hdev->asic_funcs->read_pte(hdev, hop_pte_addr);
+
+       /* hop 1 */
+       hop_addr = get_next_hop_addr(hop_pte);
+       if (hop_addr == ULLONG_MAX)
+               goto not_mapped;
+       hop_pte_addr = get_hop1_pte_addr(ctx, hop_addr, virt_addr);
+       hop_pte = hdev->asic_funcs->read_pte(hdev, hop_pte_addr);
+
+       /* hop 2 */
+       hop_addr = get_next_hop_addr(hop_pte);
+       if (hop_addr == ULLONG_MAX)
+               goto not_mapped;
+       hop_pte_addr = get_hop2_pte_addr(ctx, hop_addr, virt_addr);
+       hop_pte = hdev->asic_funcs->read_pte(hdev, hop_pte_addr);
+
+       /* hop 3 */
+       hop_addr = get_next_hop_addr(hop_pte);
+       if (hop_addr == ULLONG_MAX)
+               goto not_mapped;
+       hop_pte_addr = get_hop3_pte_addr(ctx, hop_addr, virt_addr);
+       hop_pte = hdev->asic_funcs->read_pte(hdev, hop_pte_addr);
+
+       if (!(hop_pte & LAST_MASK)) {
+               /* hop 4 */
+               hop_addr = get_next_hop_addr(hop_pte);
+               if (hop_addr == ULLONG_MAX)
+                       goto not_mapped;
+               hop_pte_addr = get_hop4_pte_addr(ctx, hop_addr, virt_addr);
+               hop_pte = hdev->asic_funcs->read_pte(hdev, hop_pte_addr);
+       }
+
+       if (!(hop_pte & PAGE_PRESENT_MASK))
+               goto not_mapped;
+
+       *phys_addr = (hop_pte & PTE_PHYS_ADDR_MASK) | (virt_addr & OFFSET_MASK);
+
+       goto out;
+
+not_mapped:
+       dev_err(hdev->dev, "virt addr 0x%llx is not mapped to phys addr\n",
+                       virt_addr);
+       rc = -EINVAL;
+out:
+       mutex_unlock(&ctx->mmu_lock);
+       return rc;
+}
+
 static ssize_t hl_data_read32(struct file *f, char __user *buf,
                                        size_t count, loff_t *ppos)
 {
        struct hl_dbg_device_entry *entry = file_inode(f)->i_private;
        struct hl_device *hdev = entry->hdev;
+       struct asic_fixed_properties *prop = &hdev->asic_prop;
        char tmp_buf[32];
+       u64 addr = entry->addr;
        u32 val;
        ssize_t rc;
 
        if (*ppos)
                return 0;
 
-       rc = hdev->asic_funcs->debugfs_read32(hdev, entry->addr, &val);
+       if (addr >= prop->va_space_dram_start_address &&
+                       addr < prop->va_space_dram_end_address &&
+                       hdev->mmu_enable &&
+                       hdev->dram_supports_virtual_memory) {
+               rc = device_va_to_pa(hdev, entry->addr, &addr);
+               if (rc)
+                       return rc;
+       }
+
+       rc = hdev->asic_funcs->debugfs_read32(hdev, addr, &val);
        if (rc) {
-               dev_err(hdev->dev, "Failed to read from 0x%010llx\n",
-                       entry->addr);
+               dev_err(hdev->dev, "Failed to read from 0x%010llx\n", addr);
                return rc;
        }
 
@@ -536,6 +611,8 @@ static ssize_t hl_data_write32(struct file *f, const char 
__user *buf,
 {
        struct hl_dbg_device_entry *entry = file_inode(f)->i_private;
        struct hl_device *hdev = entry->hdev;
+       struct asic_fixed_properties *prop = &hdev->asic_prop;
+       u64 addr = entry->addr;
        u32 value;
        ssize_t rc;
 
@@ -543,10 +620,19 @@ static ssize_t hl_data_write32(struct file *f, const char 
__user *buf,
        if (rc)
                return rc;
 
-       rc = hdev->asic_funcs->debugfs_write32(hdev, entry->addr, value);
+       if (addr >= prop->va_space_dram_start_address &&
+                       addr < prop->va_space_dram_end_address &&
+                       hdev->mmu_enable &&
+                       hdev->dram_supports_virtual_memory) {
+               rc = device_va_to_pa(hdev, entry->addr, &addr);
+               if (rc)
+                       return rc;
+       }
+
+       rc = hdev->asic_funcs->debugfs_write32(hdev, addr, value);
        if (rc) {
                dev_err(hdev->dev, "Failed to write 0x%08x to 0x%010llx\n",
-                       value, entry->addr);
+                       value, addr);
                return rc;
        }
 
-- 
2.17.1