Re: [PATCH v2 6/7] drm/i915/mtl: Adding function to send command to GSC CS

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On Tue, 13 Dec 2022, Suraj Kandpal <suraj.kandpal@xxxxxxxxx> wrote:
> Adding function that takes care of sending command to gsc cs. We start
> of with allocation of memory for our command intel_hdcp_gsc_message that
> contains gsc cs memory header as directed in specs followed by the
> actual payload hdcp message that we want to send.
> Spec states that we need to poll pending bit of response header around
> 20 times each try being 50ms apart hence adding that to current
> gsc_msg_send function
> Also we use the same function to take care of both sending and receiving
> hence no separate function to get the response.
>
> Cc: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx>
> Cc: Uma Shankar <uma.shankar@xxxxxxxxx>
> Cc: Anshuman Gupta <anshuman.gupta@xxxxxxxxx>
> Signed-off-by: Suraj Kandpal <suraj.kandpal@xxxxxxxxx>
> ---
>  drivers/gpu/drm/i915/Makefile                 |   1 +
>  drivers/gpu/drm/i915/display/intel_hdcp_gsc.c | 207 ++++++++++++++++++
>  drivers/gpu/drm/i915/display/intel_hdcp_gsc.h |  28 +++
>  drivers/gpu/drm/i915/gt/uc/intel_gsc_fwif.h   |   1 +
>  4 files changed, 237 insertions(+)
>  create mode 100644 drivers/gpu/drm/i915/display/intel_hdcp_gsc.c
>  create mode 100644 drivers/gpu/drm/i915/display/intel_hdcp_gsc.h
>
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index dfa211451a1d..42b8c3430365 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -250,6 +250,7 @@ i915-y += \
>  	display/intel_frontbuffer.o \
>  	display/intel_global_state.o \
>  	display/intel_hdcp.o \
> +	display/intel_hdcp_gsc.o \
>  	display/intel_hotplug.o \
>  	display/intel_hti.o \
>  	display/intel_lpe_audio.o \
> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp_gsc.c b/drivers/gpu/drm/i915/display/intel_hdcp_gsc.c
> new file mode 100644
> index 000000000000..aea3a1158c75
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/display/intel_hdcp_gsc.c
> @@ -0,0 +1,207 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright 2021, Intel Corporation.
> + */
> +
> +#include "i915_drv.h"
> +#include "gt/uc/intel_gsc_fw.h"
> +#include "gt/uc/intel_gsc_fwif.h"
> +#include "gem/i915_gem_region.h"
> +#include "i915_utils.h"
> +#include "display/intel_hdcp_gsc.h"

Please sort.

> +
> +struct intel_hdcp_gsc_message {
> +	struct drm_i915_gem_object *obj;
> +	struct i915_vma *vma;
> +	void *hdcp_cmd;
> +};
> +
> +/*This function helps allocate memory for the command that we will send to gsc cs */
> +static int intel_initialize_hdcp_gsc_message(struct drm_i915_private *i915,
> +					     struct intel_hdcp_gsc_message *hdcp_message)
> +{
> +	struct intel_gt *gt = i915->media_gt;
> +	struct drm_i915_gem_object *obj = NULL;
> +	struct i915_vma *vma = NULL;
> +	void *cmd;
> +	int err;
> +
> +	hdcp_message->obj = NULL;
> +	hdcp_message->hdcp_cmd = NULL;
> +	hdcp_message->vma = NULL;
> +
> +	/* allocate object of one page for HDCP command memory and store it */
> +	obj = i915_gem_object_create_shmem(gt->i915, PAGE_SIZE);
> +
> +	if (IS_ERR(obj)) {
> +		drm_err(&gt->i915->drm, "Failed to allocate HDCP streaming command!\n");
> +		return PTR_ERR(obj);
> +	}
> +
> +	cmd = i915_gem_object_pin_map_unlocked(obj, i915_coherent_map_type(gt->i915, obj, true));
> +	if (IS_ERR(cmd)) {
> +		drm_err(&gt->i915->drm, "Failed to map gsc message page!\n");
> +		err = PTR_ERR(cmd);
> +		goto out_unpin;
> +	}
> +
> +	vma = i915_vma_instance(obj, &gt->ggtt->vm, NULL);
> +	if (IS_ERR(vma)) {
> +		err = PTR_ERR(vma);
> +		goto out_unmap;
> +	}
> +
> +	err = i915_vma_pin(vma, 0, 0, PIN_GLOBAL);
> +	if (err)
> +		goto out_unmap;
> +
> +	memset(cmd, 0, obj->base.size);
> +
> +	hdcp_message->obj = obj;
> +	hdcp_message->hdcp_cmd = cmd;
> +	hdcp_message->vma = vma;
> +
> +	return 0;
> +
> +out_unmap:
> +	i915_gem_object_unpin_map(obj);
> +out_unpin:
> +	i915_gem_object_put(obj);
> +	return err;
> +}
> +
> +static void intel_free_hdcp_gsc_message(struct intel_hdcp_gsc_message *hdcp_message)
> +{
> +	struct drm_i915_gem_object *obj = fetch_and_zero(&hdcp_message->obj);
> +
> +	if (!obj)
> +		return;
> +
> +	if (hdcp_message->vma)
> +		i915_vma_unpin(fetch_and_zero(&hdcp_message->vma));
> +
> +	i915_gem_object_unpin_map(obj);
> +	i915_gem_object_put(obj);
> +	kfree(hdcp_message);
> +}
> +
> +static int intel_gsc_send_sync(struct drm_i915_private *i915,
> +			       struct intel_gsc_mtl_header *header, u64 addr,
> +			       size_t msg_out_len)
> +{
> +	struct intel_gt *gt = i915->media_gt;
> +	int ret;
> +
> +	header->flags = 0;
> +	ret = intel_gsc_fw_heci_send(&gt->uc.gsc, addr, header->message_size,
> +				     addr, msg_out_len + sizeof(*header));
> +	if (ret) {
> +		drm_err(&i915->drm, "failed to send gsc HDCP msg (%d)\n", ret);
> +		return ret;
> +	}
> +	/*
> +	 * Checking validity marker for memory sanity
> +	 */
> +	if (header->validity_marker != GSC_HECI_VALIDITY_MARKER) {
> +		drm_err(&i915->drm, "invalid validity marker\n");
> +		return -EINVAL;
> +	}
> +
> +	if (header->status != 0) {
> +		drm_err(&i915->drm, "header status indicates error %d\n",
> +			header->status);
> +		return -EINVAL;
> +	}
> +
> +	if (header->flags & INTEL_GSC_MSG_PENDING)
> +		return -EAGAIN;
> +
> +	return 0;
> +}
> +
> +/*
> + * This function can now be used for sending requests and will also handle
> + * receipt of reply messages hence no different function of message retrieval
> + * is required. We will initialize intel_hdcp_gsc_message structure then add
> + * gsc cs memory header as stated in specs after which the normal HDCP payload
> + * will follow
> + */
> +ssize_t intel_hdcp_gsc_msg_send(struct drm_i915_private *i915, u8 *msg_in,
> +				size_t msg_in_len, u8 *msg_out, size_t msg_out_len)
> +{
> +	struct intel_gt *gt = i915->media_gt;
> +	struct intel_gsc_mtl_header *header;
> +	const size_t max_msg_size = PAGE_SIZE - sizeof(*header);
> +	struct intel_hdcp_gsc_message *hdcp_message;
> +	u64 addr;
> +	u32 reply_size;
> +	int ret, tries = 0;
> +
> +	if (!intel_uc_uses_gsc_uc(&gt->uc))
> +		return -ENODEV;
> +
> +	if (msg_in_len > max_msg_size || msg_out_len > max_msg_size)
> +		return -ENOSPC;
> +
> +	hdcp_message = kzalloc(sizeof(*hdcp_message), GFP_KERNEL);
> +
> +	if (!hdcp_message)
> +		return -ENOMEM;
> +
> +	ret = intel_initialize_hdcp_gsc_message(i915, hdcp_message);
> +
> +	if (ret) {
> +		drm_err(&i915->drm,
> +			"Could not initialize hdcp_message\n");
> +		goto err;
> +	}
> +
> +	header = hdcp_message->hdcp_cmd;
> +	addr = i915_ggtt_offset(hdcp_message->vma);
> +
> +	memset(header, 0, sizeof(*header));
> +	header->validity_marker = GSC_HECI_VALIDITY_MARKER;
> +	header->gsc_address = HECI_MEADDRESS_HDCP;
> +	header->host_session_handle = 0;
> +	header->header_version = MTL_GSC_HEADER_VERSION;
> +	header->message_size = msg_in_len + sizeof(*header);
> +
> +	memcpy(hdcp_message->hdcp_cmd + sizeof(*header), 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 = intel_gsc_send_sync(i915, header, addr, msg_out_len);
> +
> +		/* Only try again if gsc says so */
> +		if (ret != -EAGAIN)
> +			break;
> +
> +		msleep(50);
> +
> +	} while (++tries < 20);
> +
> +	if (ret)
> +		goto err;
> +
> +	/* we use the same mem for the reply, so header is in the same loc */
> +	reply_size = header->message_size - sizeof(*header);
> +	if (reply_size > msg_out_len) {
> +		drm_warn(&i915->drm, "caller with insufficient HDCP reply size %u (%d)\n",
> +			 reply_size, (u32)msg_out_len);
> +		reply_size = msg_out_len;
> +	} else if (reply_size != msg_out_len) {
> +		drm_dbg_kms(&i915->drm, "caller unexpected HCDP reply size %u (%d)\n",
> +			    reply_size, (u32)msg_out_len);
> +	}
> +
> +	memcpy(msg_out, hdcp_message->hdcp_cmd + sizeof(*header), msg_out_len);
> +
> +err:
> +	intel_free_hdcp_gsc_message(hdcp_message);
> +	return ret;
> +}
> diff --git a/drivers/gpu/drm/i915/display/intel_hdcp_gsc.h b/drivers/gpu/drm/i915/display/intel_hdcp_gsc.h
> new file mode 100644
> index 000000000000..9f3e3880fe0a
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/display/intel_hdcp_gsc.h
> @@ -0,0 +1,28 @@
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright © 2021 Intel Corporation
> + */
> +
> +#ifndef __INTEL_HDCP_GSC_H__
> +#define __INTEL_HDCP_GSC_H__
> +
> +#include <linux/types.h>
> +#include <linux/err.h>
> +/*
> + * FIXME: Spec states that we need to create a random
> + * host session everytime we send message for now creating
> + * a static host session to avoid clashes not using this
> + * header as of now as we see an error if we use anything
> + * other than 0 as host session
> + */
> +#define GSC_HDCP_HOST_HANDLE	0x12233FFEEDD00000

This is unused.

> +
> +struct drm_i915_private;
> +
> +ssize_t intel_hdcp_gsc_msg_send(struct drm_i915_private *i915, u8 *msg_in,
> +				size_t msg_in_len, u8 *msg_out,
> +				size_t msg_out_len);
> +int intel_gsc_hdcp_init(struct drm_i915_private *i915);
> +int intel_gsc_hdcp_fini(struct drm_i915_private *i915);

The function naming needs to match file name.

intel_hdcp_gsc.[ch] -> intel_hdcp_gsc_xxx().

BR,
Jani.

> +
> +#endif /* __INTEL_HDCP_GCS_H__ */
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_gsc_fwif.h b/drivers/gpu/drm/i915/gt/uc/intel_gsc_fwif.h
> index 1c2a04d092a8..19b98c75367a 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_gsc_fwif.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_gsc_fwif.h
> @@ -34,6 +34,7 @@ struct intel_gsc_mtl_header {
>  	 * Bits 16-31: Extension Size
>  	 */
>  	u32 flags;
> +#define INTEL_GSC_MSG_PENDING	1
>  
>  	u32 status;
>  } __packed;

-- 
Jani Nikula, Intel Open Source Graphics Center




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