[PATCH v2] drm/hdcp: optimizing the srm handling

27 Jan 2020

As we are not using the sysfs infrastructure anymore, link to it is
removed. And global srm data and mutex to protect it are removed,
with required handling at revocation check function.
v2:
  srm_data is dropped and few more comments are addressed.
Signed-off-by: Ramalingam C ramalingam.c@intel.com
Suggested-by: Sean Paul seanpaul@chromium.org
---
 drivers/gpu/drm/drm_hdcp.c     | 144 ++++++++++++---------------------
 drivers/gpu/drm/drm_internal.h |   4 -
 drivers/gpu/drm/drm_sysfs.c    |   2 -
 include/drm/drm_hdcp.h         |   4 +-
 4 files changed, 55 insertions(+), 99 deletions(-)

diff --git a/drivers/gpu/drm/drm_hdcp.c b/drivers/gpu/drm/drm_hdcp.c
index 9191633a3c43..30749a13108e 100644
--- a/drivers/gpu/drm/drm_hdcp.c
+++ b/drivers/gpu/drm/drm_hdcp.c
@@ -23,14 +23,6 @@
#include "drm_internal.h"
-static struct hdcp_srm {
-	u32 revoked_ksv_cnt;
-	u8 *revoked_ksv_list;
-
-	/* Mutex to protect above struct member */
-	struct mutex mutex;
-} *srm_data;
-
 static inline void drm_hdcp_print_ksv(const u8 *ksv)
 {
    DRM_DEBUG("\t%#02x, %#02x, %#02x, %#02x, %#02x\n",
@@ -91,7 +83,8 @@ static inline u32 get_vrl_length(const u8 *buf)
    return drm_hdcp_be24_to_cpu(buf);
 }
-static int drm_hdcp_parse_hdcp1_srm(const u8 *buf, size_t count)
+static int drm_hdcp_parse_hdcp1_srm(const u8 *buf, size_t count,
+				    u8 *revoked_ksv_list, u32 *revoked_ksv_cnt)
 {
    struct hdcp_srm_header *header;
    u32 vrl_length, ksv_count;
@@ -131,29 +124,28 @@ static int drm_hdcp_parse_hdcp1_srm(const u8 *buf, size_t count)
    ksv_count = drm_hdcp_get_revoked_ksv_count(buf, vrl_length);
    if (!ksv_count) {
    	DRM_DEBUG("Revoked KSV count is 0\n");
-		return count;
+		return 0;
    }
-	kfree(srm_data->revoked_ksv_list);
-	srm_data->revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN,
-					     GFP_KERNEL);
-	if (!srm_data->revoked_ksv_list) {
+	revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN, GFP_KERNEL);
+	if (!revoked_ksv_list) {
    	DRM_ERROR("Out of Memory\n");
    	return -ENOMEM;
    }
-	if (drm_hdcp_get_revoked_ksvs(buf, srm_data->revoked_ksv_list,
+	if (drm_hdcp_get_revoked_ksvs(buf, revoked_ksv_list,
    			      vrl_length) != ksv_count) {
-		srm_data->revoked_ksv_cnt = 0;
-		kfree(srm_data->revoked_ksv_list);
+		*revoked_ksv_cnt = 0;
+		kfree(revoked_ksv_list);
    	return -EINVAL;
    }
-	srm_data->revoked_ksv_cnt = ksv_count;
-	return count;
+	*revoked_ksv_cnt = ksv_count;
+	return 0;
 }
-static int drm_hdcp_parse_hdcp2_srm(const u8 *buf, size_t count)
+static int drm_hdcp_parse_hdcp2_srm(const u8 *buf, size_t count,
+				    u8 *revoked_ksv_list, u32 *revoked_ksv_cnt)
 {
    struct hdcp_srm_header *header;
    u32 vrl_length, ksv_count, ksv_sz;
@@ -195,13 +187,11 @@ static int drm_hdcp_parse_hdcp2_srm(const u8 *buf, size_t count)
    ksv_count = (*buf << 2) | DRM_HDCP_2_KSV_COUNT_2_LSBITS(*(buf + 1));
    if (!ksv_count) {
    	DRM_DEBUG("Revoked KSV count is 0\n");
-		return count;
+		return 0;
    }
-	kfree(srm_data->revoked_ksv_list);
-	srm_data->revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN,
-					     GFP_KERNEL);
-	if (!srm_data->revoked_ksv_list) {
+	revoked_ksv_list = kcalloc(ksv_count, DRM_HDCP_KSV_LEN, GFP_KERNEL);
+	if (!revoked_ksv_list) {
    	DRM_ERROR("Out of Memory\n");
    	return -ENOMEM;
    }
@@ -210,10 +200,10 @@ static int drm_hdcp_parse_hdcp2_srm(const u8 *buf, size_t count)
    buf += DRM_HDCP_2_NO_OF_DEV_PLUS_RESERVED_SZ;
DRM_DEBUG("Revoked KSVs: %d\n", ksv_count);
-	memcpy(srm_data->revoked_ksv_list, buf, ksv_sz);
+	memcpy(revoked_ksv_list, buf, ksv_sz);
-	srm_data->revoked_ksv_cnt = ksv_count;
-	return count;
+	*revoked_ksv_cnt = ksv_count;
+	return 0;
 }
static inline bool is_srm_version_hdcp1(const u8 *buf)
@@ -226,18 +216,22 @@ static inline bool is_srm_version_hdcp2(const u8 *buf)
    return *buf == (u8)(DRM_HDCP_2_SRM_ID << 4 | DRM_HDCP_2_INDICATOR);
 }
-static void drm_hdcp_srm_update(const u8 *buf, size_t count)
+static void drm_hdcp_srm_update(const u8 *buf, size_t count,
+				u8 *revoked_ksv_list, u32 *revoked_ksv_cnt)
 {
    if (count < sizeof(struct hdcp_srm_header))
    	return;
if (is_srm_version_hdcp1(buf))
-		drm_hdcp_parse_hdcp1_srm(buf, count);
+		drm_hdcp_parse_hdcp1_srm(buf, count, revoked_ksv_list,
+					 revoked_ksv_cnt);
    else if (is_srm_version_hdcp2(buf))
-		drm_hdcp_parse_hdcp2_srm(buf, count);
+		drm_hdcp_parse_hdcp2_srm(buf, count, revoked_ksv_list,
+					 revoked_ksv_cnt);
 }
-static void drm_hdcp_request_srm(struct drm_device *drm_dev)
+static void drm_hdcp_request_srm(struct drm_device *drm_dev,
+				 u8 *revoked_ksv_list, u32 *revoked_ksv_cnt)
 {
    char fw_name[36] = "display_hdcp_srm.bin";
    const struct firmware *fw;
@@ -250,7 +244,8 @@ static void drm_hdcp_request_srm(struct drm_device *drm_dev)
    	goto exit;
if (fw->size && fw->data)
-		drm_hdcp_srm_update(fw->data, fw->size);
+		drm_hdcp_srm_update(fw->data, fw->size, revoked_ksv_list,
+				    revoked_ksv_cnt);
exit:
    release_firmware(fw);
@@ -279,70 +274,37 @@ static void drm_hdcp_request_srm(struct drm_device *drm_dev)
  * https://www.digital-cp.com/sites/default/files/specifications/HDCP%20on%20HD...
  *
  * Returns:
- * TRUE on any of the KSV is revoked, else FALSE.
+ * Count of the revoked KSVs.
  */
-bool drm_hdcp_check_ksvs_revoked(struct drm_device *drm_dev, u8 *ksvs,
-				 u32 ksv_count)
+int drm_hdcp_check_ksvs_revoked(struct drm_device *drm_dev, u8 *ksvs_in,
+				u32 ksv_count)
 {
-	u32 rev_ksv_cnt, cnt, i, j;
-	u8 *rev_ksv_list;
-
-	if (!srm_data)
-		return false;
-
-	mutex_lock(&srm_data->mutex);
-	drm_hdcp_request_srm(drm_dev);
-
-	rev_ksv_cnt = srm_data->revoked_ksv_cnt;
-	rev_ksv_list = srm_data->revoked_ksv_list;
-
-	/* If the Revoked ksv list is empty */
-	if (!rev_ksv_cnt || !rev_ksv_list) {
-		mutex_unlock(&srm_data->mutex);
-		return false;
-	}
-
-	for  (cnt = 0; cnt < ksv_count; cnt++) {
-		rev_ksv_list = srm_data->revoked_ksv_list;
-		for (i = 0; i < rev_ksv_cnt; i++) {
-			for (j = 0; j < DRM_HDCP_KSV_LEN; j++)
-				if (ksvs[j] != rev_ksv_list[j]) {
-					break;
-				} else if (j == (DRM_HDCP_KSV_LEN - 1)) {
-					DRM_DEBUG("Revoked KSV is ");
-					drm_hdcp_print_ksv(ksvs);
-					mutex_unlock(&srm_data->mutex);
-					return true;
-				}
-			/* Move the offset to next KSV in the revoked list */
-			rev_ksv_list += DRM_HDCP_KSV_LEN;
+	u8 *revoked_ksv_list = NULL, *ksvs, *list_itr;
+	u32 revoked_ksv_cnt = 0, i, j;
+	int ret = 0;
+
+	drm_hdcp_request_srm(drm_dev, revoked_ksv_list, &revoked_ksv_cnt);
+	list_itr = revoked_ksv_list;
+
+	for (i = 0; i < revoked_ksv_cnt; i++) {
+		ksvs = ksvs_in;
+		for  (j = 0; j < ksv_count; j++) {
+			if (!memcmp(ksvs, list_itr, DRM_HDCP_KSV_LEN)) {
+				DRM_DEBUG("Revoked KSV is ");
+				drm_hdcp_print_ksv(ksvs);
+				ret++;
+			}
+			/* Iterate to next ksv_offset */
+			ksvs += DRM_HDCP_KSV_LEN;
    	}
-
-		/* Iterate to next ksv_offset */
-		ksvs += DRM_HDCP_KSV_LEN;
+		/* Move the offset to next KSV in the revoked list */
+		list_itr += DRM_HDCP_KSV_LEN;
    }
-	mutex_unlock(&srm_data->mutex);
-	return false;
-}
-EXPORT_SYMBOL_GPL(drm_hdcp_check_ksvs_revoked);
-
-int drm_setup_hdcp_srm(struct class *drm_class)
-{
-	srm_data = kzalloc(sizeof(*srm_data), GFP_KERNEL);
-	if (!srm_data)
-		return -ENOMEM;
-	mutex_init(&srm_data->mutex);
-	return 0;
-}
-
-void drm_teardown_hdcp_srm(struct class *drm_class)
-{
-	if (srm_data) {
-		kfree(srm_data->revoked_ksv_list);
-		kfree(srm_data);
-	}
+	kfree(revoked_ksv_list);
+	return ret;
 }
+EXPORT_SYMBOL_GPL(drm_hdcp_check_ksvs_revoked);
static struct drm_prop_enum_list drm_cp_enum_list[] = {
    { DRM_MODE_CONTENT_PROTECTION_UNDESIRED, "Undesired" },
diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
index 6937bf923f05..a34c7f8373fa 100644
--- a/drivers/gpu/drm/drm_internal.h
+++ b/drivers/gpu/drm/drm_internal.h
@@ -235,7 +235,3 @@ int drm_syncobj_query_ioctl(struct drm_device *dev, void *data,
 void drm_framebuffer_print_info(struct drm_printer *p, unsigned int indent,
    			const struct drm_framebuffer *fb);
 int drm_framebuffer_debugfs_init(struct drm_minor *minor);
-
-/* drm_hdcp.c */
-int drm_setup_hdcp_srm(struct class *drm_class);
-void drm_teardown_hdcp_srm(struct class *drm_class);
diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
index dd2bc85f43cc..2e83c3d72af9 100644
--- a/drivers/gpu/drm/drm_sysfs.c
+++ b/drivers/gpu/drm/drm_sysfs.c
@@ -85,7 +85,6 @@ int drm_sysfs_init(void)
    }
drm_class->devnode = drm_devnode;
-	drm_setup_hdcp_srm(drm_class);
    return 0;
 }
@@ -98,7 +97,6 @@ void drm_sysfs_destroy(void)
 {
    if (IS_ERR_OR_NULL(drm_class))
    	return;
-	drm_teardown_hdcp_srm(drm_class);
    class_remove_file(drm_class, &class_attr_version.attr);
    class_destroy(drm_class);
    drm_class = NULL;
diff --git a/include/drm/drm_hdcp.h b/include/drm/drm_hdcp.h
index 06a11202a097..d512089b873f 100644
--- a/include/drm/drm_hdcp.h
+++ b/include/drm/drm_hdcp.h
@@ -288,8 +288,8 @@ struct hdcp_srm_header {
 struct drm_device;
 struct drm_connector;
-bool drm_hdcp_check_ksvs_revoked(struct drm_device *dev,
-				 u8 *ksvs, u32 ksv_count);
+int drm_hdcp_check_ksvs_revoked(struct drm_device *dev,
+				u8 *ksvs, u32 ksv_count);
 int drm_connector_attach_content_protection_property(
    	struct drm_connector *connector, bool hdcp_content_type);
 void drm_hdcp_update_content_protection(struct drm_connector *connector,
-- 
2.20.1


    

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[PATCH v2] drm/hdcp: optimizing the srm handling