On 2/9/2024 2:14 AM, Suraj Kandpal wrote:
Enable HDCP for Xe by defining functions which take care of
interaction of HDCP as a client with the GSC CS interface.

--v2
-add kfree at appropriate place [Daniele]
-remove useless define [Daniele]
-move host session logic to xe_gsc_submit.c [Daniele]
-call xe_gsc_check_and_update_pending directly in an if condition
[Daniele]
-use xe_device instead of drm_i915_private [Daniele]

--v3
-use xe prefix for newly exposed function [Daniele]
-remove client specific defines from intel_gsc_mtl_header [Daniele]
-add missing kfree() [Daniele]
-have NULL check for hdcp_message in finish function [Daniele]
-dont have too many variable declarations in the same line [Daniele]

Signed-off-by: Suraj Kandpal <suraj.kand...@intel.com>
---
  drivers/gpu/drm/xe/display/xe_hdcp_gsc.c | 180 ++++++++++++++++++++++-
  drivers/gpu/drm/xe/xe_gsc_submit.c       |  15 ++
  drivers/gpu/drm/xe/xe_gsc_submit.h       |   1 +
  3 files changed, 193 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/xe/display/xe_hdcp_gsc.c 
b/drivers/gpu/drm/xe/display/xe_hdcp_gsc.c
index 425db3532ce5..aa8c13916bb6 100644
--- a/drivers/gpu/drm/xe/display/xe_hdcp_gsc.c
+++ b/drivers/gpu/drm/xe/display/xe_hdcp_gsc.c
@@ -4,12 +4,27 @@
   */
#include <drm/drm_print.h>
+#include <linux/delay.h>
+#include "abi/gsc_command_header_abi.h"
  #include "intel_hdcp_gsc.h"
  #include "xe_device_types.h"
  #include "xe_gt.h"
  #include "xe_gsc_proxy.h"
  #include "xe_pm.h"
+#include "xe_bo.h"
+#include "xe_map.h"
+#include "xe_gsc_submit.h"
+
+#define HECI_MEADDRESS_HDCP 18
+
+struct intel_hdcp_gsc_message {
+       struct xe_bo *hdcp_bo;
+       u64 hdcp_cmd_in;
+       u64 hdcp_cmd_out;
+};
+
+#define HDCP_GSC_HEADER_SIZE sizeof(struct intel_gsc_mtl_header)
bool intel_hdcp_gsc_cs_required(struct xe_device *xe)
  {
@@ -40,19 +55,178 @@ bool intel_hdcp_gsc_check_status(struct xe_device *xe)
        return ret;
  }
+/*This function helps allocate memory for the command that we will send to gsc cs */
+static int intel_hdcp_gsc_initialize_message(struct xe_device *xe,
+                                            struct intel_hdcp_gsc_message 
*hdcp_message)
+{
+       struct xe_bo *bo = NULL;
+       u64 cmd_in, cmd_out;
+       int ret = 0;
+
+       /* allocate object of two page for HDCP command memory and store it */
+       xe_device_mem_access_get(xe);
+       bo = xe_bo_create_pin_map(xe, xe_device_get_root_tile(xe), NULL, 
PAGE_SIZE * 2,
+                                 ttm_bo_type_kernel,
+                                 XE_BO_CREATE_SYSTEM_BIT |
+                                 XE_BO_CREATE_GGTT_BIT);
+
+       if (IS_ERR(bo)) {
+               drm_err(&xe->drm, "Failed to allocate bo for HDCP streaming 
command!\n");
+               ret = PTR_ERR(bo);
+               goto out;
+       }
+
+       cmd_in = xe_bo_ggtt_addr(bo);
+       cmd_out = cmd_in + PAGE_SIZE;
+       xe_map_memset(xe, &bo->vmap, 0, 0, bo->size);
+
+       hdcp_message->hdcp_bo = bo;
+       hdcp_message->hdcp_cmd_in = cmd_in;
+       hdcp_message->hdcp_cmd_out = cmd_out;
+out:
+       xe_device_mem_access_put(xe);
+       return ret;
+}
+
+static int intel_hdcp_gsc_hdcp2_init(struct xe_device *xe)
+{
+       struct intel_hdcp_gsc_message *hdcp_message;
+       int ret;
+
+       hdcp_message = kzalloc(sizeof(*hdcp_message), GFP_KERNEL);
+
+       if (!hdcp_message)
+               return -ENOMEM;
+
+       /*
+        * NOTE: No need to lock the comp mutex here as it is already
+        * going to be taken before this function called
+        */
+       ret = intel_hdcp_gsc_initialize_message(xe, hdcp_message);
+       xe->display.hdcp.hdcp_message = hdcp_message;
+
+       if (ret) {
+               drm_err(&xe->drm, "Could not initialize hdcp_message\n");
+               kfree(hdcp_message);

Here you're leaving xe->display.hdcp.hdcp_message pointing to a memory location that we no longer own. is that safe for the _fini function?

LGTM apart from this (assuming it is going to be squashed with the next patch for merge).

Daniele

+       }
+
+       return ret;
+}
+
  int intel_hdcp_gsc_init(struct xe_device *xe)
  {
-       drm_dbg_kms(&xe->drm, "HDCP support not yet implemented\n");
-       return -ENODEV;
+       struct i915_hdcp_arbiter *data;
+       int ret;
+
+       data = kzalloc(sizeof(*data), GFP_KERNEL);
+       if (!data)
+               return -ENOMEM;
+
+       mutex_lock(&xe->display.hdcp.hdcp_mutex);
+       xe->display.hdcp.arbiter = data;
+       xe->display.hdcp.arbiter->hdcp_dev = xe->drm.dev;
+       xe->display.hdcp.arbiter->ops = &gsc_hdcp_ops;
+       ret = intel_hdcp_gsc_hdcp2_init(xe);
+       if (ret)
+               kfree(data);
+
+       mutex_unlock(&xe->display.hdcp.hdcp_mutex);
+
+       return ret;
  }
void intel_hdcp_gsc_fini(struct xe_device *xe)
  {
+       struct intel_hdcp_gsc_message *hdcp_message =
+                                       xe->display.hdcp.hdcp_message;
+
+       if (!hdcp_message)
+               return;
+
+       xe_bo_unpin_map_no_vm(hdcp_message->hdcp_bo);
+       kfree(hdcp_message);
+}
+
+static int xe_gsc_send_sync(struct xe_device *xe,
+                           struct intel_hdcp_gsc_message *hdcp_message,
+                           u32 msg_size_in, u32 msg_size_out,
+                           u32 addr_out_off)
+{
+       struct xe_gt *gt = hdcp_message->hdcp_bo->tile->media_gt;
+       struct iosys_map *map = &hdcp_message->hdcp_bo->vmap;
+       struct xe_gsc *gsc = &gt->uc.gsc;
+       int ret;
+
+       ret = xe_gsc_pkt_submit_kernel(gsc, hdcp_message->hdcp_cmd_in, 
msg_size_in,
+                                      hdcp_message->hdcp_cmd_out, 
msg_size_out);
+       if (ret) {
+               drm_err(&xe->drm, "failed to send gsc HDCP msg (%d)\n", ret);
+               return ret;
+       }
+
+       if (xe_gsc_check_and_update_pending(xe, map, 0, map, addr_out_off))
+               return -EAGAIN;
+
+       ret = xe_gsc_read_out_header(xe, map, addr_out_off,
+                                    sizeof(struct hdcp_cmd_header), NULL);
+
+       return ret;
  }
ssize_t intel_hdcp_gsc_msg_send(struct xe_device *xe, u8 *msg_in,
                                size_t msg_in_len, u8 *msg_out,
                                size_t msg_out_len)
  {
-       return -ENODEV;
+       const size_t max_msg_size = PAGE_SIZE - HDCP_GSC_HEADER_SIZE;
+       struct intel_hdcp_gsc_message *hdcp_message;
+       u64 host_session_id;
+       u32 msg_size_in, msg_size_out;
+       u32 addr_out_off, addr_in_wr_off = 0;
+       int ret, tries = 0;
+
+       if (msg_in_len > max_msg_size || msg_out_len > max_msg_size) {
+               ret = -ENOSPC;
+               goto out;
+       }
+
+       msg_size_in = msg_in_len + HDCP_GSC_HEADER_SIZE;
+       msg_size_out = msg_out_len + HDCP_GSC_HEADER_SIZE;
+       hdcp_message = xe->display.hdcp.hdcp_message;
+       addr_out_off = PAGE_SIZE;
+
+       host_session_id = xe_gsc_create_host_session_id();
+       xe_device_mem_access_get(xe);
+       addr_in_wr_off = xe_gsc_emit_header(xe, &hdcp_message->hdcp_bo->vmap,
+                                           addr_in_wr_off, HECI_MEADDRESS_HDCP,
+                                           host_session_id, msg_in_len);
+       xe_map_memcpy_to(xe, &hdcp_message->hdcp_bo->vmap, addr_in_wr_off,
+                        msg_in, msg_in_len);
+       /*
+        * Keep sending request in case the pending bit is set no need to add
+        * message handle as we are using same address hence loc. of header is
+        * same and it will contain the message handle. we will send the message
+        * 20 times each message 50 ms apart
+        */
+       do {
+               ret = xe_gsc_send_sync(xe, hdcp_message, msg_size_in, 
msg_size_out,
+                                      addr_out_off);
+
+               /* Only try again if gsc says so */
+               if (ret != -EAGAIN)
+                       break;
+
+               msleep(50);
+
+       } while (++tries < 20);
+
+       if (ret)
+               goto out;
+
+       xe_map_memcpy_from(xe, msg_out, &hdcp_message->hdcp_bo->vmap,
+                          addr_out_off + HDCP_GSC_HEADER_SIZE,
+                          msg_out_len);
+
+out:
+       xe_device_mem_access_put(xe);
+       return ret;
  }
diff --git a/drivers/gpu/drm/xe/xe_gsc_submit.c 
b/drivers/gpu/drm/xe/xe_gsc_submit.c
index 348994b271be..9a18f5667db3 100644
--- a/drivers/gpu/drm/xe/xe_gsc_submit.c
+++ b/drivers/gpu/drm/xe/xe_gsc_submit.c
@@ -40,6 +40,21 @@ gsc_to_gt(struct xe_gsc *gsc)
        return container_of(gsc, struct xe_gt, uc.gsc);
  }
+/**
+ * xe_gsc_get_host_session_id - Creates a random 64 bit host_session id with
+ * bits 56-63 masked.
+ *
+ * Returns: random host_session_id which can be used to send messages to gsc cs
+ */
+u64 xe_gsc_create_host_session_id(void)
+{
+       u64 host_session_id;
+
+       get_random_bytes(&host_session_id, sizeof(u64));
+       host_session_id &= ~HOST_SESSION_CLIENT_MASK;
+       return host_session_id;
+}
+
  /**
   * xe_gsc_emit_header - write the MTL GSC header in memory
   * @xe: the Xe device
diff --git a/drivers/gpu/drm/xe/xe_gsc_submit.h 
b/drivers/gpu/drm/xe/xe_gsc_submit.h
index 1939855031a6..1416b5745a4c 100644
--- a/drivers/gpu/drm/xe/xe_gsc_submit.h
+++ b/drivers/gpu/drm/xe/xe_gsc_submit.h
@@ -28,4 +28,5 @@ int xe_gsc_read_out_header(struct xe_device *xe,
  int xe_gsc_pkt_submit_kernel(struct xe_gsc *gsc, u64 addr_in, u32 size_in,
                             u64 addr_out, u32 size_out);
+u64 xe_gsc_create_host_session_id(void);
  #endif

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