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Message-ID: <62de5467-a979-4739-aee3-e00472ab192a@linaro.org>
Date: Mon, 18 Dec 2023 20:46:06 +0200
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Subject: Re: [PATCH v2 08/34] media: iris: introduce state machine for iris
 core
Content-Language: en-GB
To: Dikshita Agarwal <quic_dikshita@quicinc.com>,
 linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
 stanimir.k.varbanov@gmail.com, quic_vgarodia@quicinc.com, agross@kernel.org,
 andersson@kernel.org, konrad.dybcio@linaro.org, mchehab@kernel.org,
 bryan.odonoghue@linaro.org
Cc: linux-arm-msm@vger.kernel.org, quic_abhinavk@quicinc.com
References: <1702899149-21321-1-git-send-email-quic_dikshita@quicinc.com>
 <1702899149-21321-9-git-send-email-quic_dikshita@quicinc.com>
From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
In-Reply-To: <1702899149-21321-9-git-send-email-quic_dikshita@quicinc.com>
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On 18/12/2023 13:32, Dikshita Agarwal wrote:
> Introduces different states for core. State transitions
> are defined, based on which they would be allowed/rejected/ignored.
> 
> IRIS_CORE_DEINIT - default state.
> IRIS_CORE_INIT_WAIT -  wait state for video core to complete
> initialization.
> IRIS_CORE_INIT - core state with core initialized. FW loaded and
> HW brought out of reset, shared queues established between host
> driver and firmware.
> IRIS_CORE_ERROR - error state.
> 
>              |
>              v
>         -----------
>    +--->| DEINIT  |<---+
>    |    -----------    |
>    |         |         |
>    |         v         |
>    |    -----------    |
>    |    |INIT_WAIT|    |
>    |    -----------    |
>    |      /     \      |
>    |     /       \     |
>    |    /         \    |
>    |   v           v   v
>   -----------   ----------.
>   |  INIT   |-->|  ERROR |
>   -----------   ----------.
> 
> Signed-off-by: Dikshita Agarwal <quic_dikshita@quicinc.com>

Can we see users for this API please? Otherwise it's just a dead code.

> ---
>   drivers/media/platform/qcom/vcodec/iris/Makefile   |  3 +-
>   .../media/platform/qcom/vcodec/iris/iris_core.h    |  4 ++
>   .../media/platform/qcom/vcodec/iris/iris_state.c   | 64 ++++++++++++++++++++++
>   .../media/platform/qcom/vcodec/iris/iris_state.h   | 22 ++++++++
>   4 files changed, 92 insertions(+), 1 deletion(-)
>   create mode 100644 drivers/media/platform/qcom/vcodec/iris/iris_state.c
>   create mode 100644 drivers/media/platform/qcom/vcodec/iris/iris_state.h
> 
> diff --git a/drivers/media/platform/qcom/vcodec/iris/Makefile b/drivers/media/platform/qcom/vcodec/iris/Makefile
> index 0748819..12a74de 100644
> --- a/drivers/media/platform/qcom/vcodec/iris/Makefile
> +++ b/drivers/media/platform/qcom/vcodec/iris/Makefile
> @@ -1,4 +1,5 @@
>   iris-objs += iris_probe.o \
> -             resources.o
> +             resources.o \
> +             iris_state.o
>   
>   obj-$(CONFIG_VIDEO_QCOM_IRIS) += iris.o
> diff --git a/drivers/media/platform/qcom/vcodec/iris/iris_core.h b/drivers/media/platform/qcom/vcodec/iris/iris_core.h
> index c2bc95d..56a5b7d 100644
> --- a/drivers/media/platform/qcom/vcodec/iris/iris_core.h
> +++ b/drivers/media/platform/qcom/vcodec/iris/iris_core.h
> @@ -9,6 +9,8 @@
>   #include <linux/types.h>
>   #include <media/v4l2-device.h>
>   
> +#include "iris_state.h"
> +
>   /**
>    * struct iris_core - holds core parameters valid for all instances
>    *
> @@ -27,6 +29,7 @@
>    * @clk_count: count of iris clocks
>    * @reset_tbl: table of iris reset clocks
>    * @reset_count: count of iris reset clocks
> + * @state: current state of core
>    */
>   
>   struct iris_core {
> @@ -45,6 +48,7 @@ struct iris_core {
>   	u32					clk_count;
>   	struct reset_info			*reset_tbl;
>   	u32					reset_count;
> +	enum iris_core_state			state;
>   };
>   
>   #endif
> diff --git a/drivers/media/platform/qcom/vcodec/iris/iris_state.c b/drivers/media/platform/qcom/vcodec/iris/iris_state.c
> new file mode 100644
> index 0000000..22557af
> --- /dev/null
> +++ b/drivers/media/platform/qcom/vcodec/iris/iris_state.c
> @@ -0,0 +1,64 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#include "iris_core.h"
> +#include "iris_state.h"
> +
> +#define IRIS_STATE(name)[IRIS_CORE_##name] = "CORE_"#name

Inline this please.

> +
> +static const char * const core_state_names[] = {
> +	IRIS_STATE(DEINIT),
> +	IRIS_STATE(INIT_WAIT),
> +	IRIS_STATE(INIT),
> +	IRIS_STATE(ERROR),
> +};
> +
> +#undef IRIS_STATE
> +
> +bool core_in_valid_state(struct iris_core *core)

So, even in your driver you have global names? That's really ugh. Please 
fix them.

> +{
> +	return core->state == IRIS_CORE_INIT ||
> +		core->state == IRIS_CORE_INIT_WAIT;
> +}
> +
> +static const char *core_state_name(enum iris_core_state state)
> +{
> +	if ((unsigned int)state < ARRAY_SIZE(core_state_names))
> +		return core_state_names[state];
> +
> +	return "UNKNOWN_STATE";
> +}
> +
> +static bool iris_allow_core_state_change(struct iris_core *core,
> +					 enum iris_core_state req_state)
> +{
> +	if (core->state == IRIS_CORE_DEINIT)
> +		return req_state == IRIS_CORE_INIT_WAIT || req_state == IRIS_CORE_ERROR;
> +	else if (core->state == IRIS_CORE_INIT_WAIT)
> +		return req_state == IRIS_CORE_INIT || req_state == IRIS_CORE_ERROR;
> +	else if (core->state == IRIS_CORE_INIT)
> +		return req_state == IRIS_CORE_DEINIT || req_state == IRIS_CORE_ERROR;
> +	else if (core->state == IRIS_CORE_ERROR)
> +		return req_state == IRIS_CORE_DEINIT;
> +
> +	dev_warn(core->dev, "core state change %s -> %s is not allowed\n",
> +		 core_state_name(core->state), core_state_name(req_state));
> +
> +	return false;
> +}
> +
> +int iris_change_core_state(struct iris_core *core,
> +			   enum iris_core_state request_state)
> +{
> +	if (core->state == request_state)
> +		return 0;
> +
> +	if (!iris_allow_core_state_change(core, request_state))
> +		return -EINVAL;
> +
> +	core->state = request_state;
> +
> +	return 0;
> +}
> diff --git a/drivers/media/platform/qcom/vcodec/iris/iris_state.h b/drivers/media/platform/qcom/vcodec/iris/iris_state.h
> new file mode 100644
> index 0000000..ee20842
> --- /dev/null
> +++ b/drivers/media/platform/qcom/vcodec/iris/iris_state.h
> @@ -0,0 +1,22 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#ifndef _IRIS_STATE_H_
> +#define _IRIS_STATE_H_
> +
> +struct iris_core;
> +
> +enum iris_core_state {
> +	IRIS_CORE_DEINIT,
> +	IRIS_CORE_INIT_WAIT,
> +	IRIS_CORE_INIT,
> +	IRIS_CORE_ERROR,
> +};
> +
> +bool core_in_valid_state(struct iris_core *core);
> +int iris_change_core_state(struct iris_core *core,
> +			   enum iris_core_state request_state);
> +
> +#endif

-- 
With best wishes
Dmitry