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Message-ID: <c9ec63d0-7b41-1757-b8d0-47d07cb50d1f@linaro.org>
Date:   Mon, 12 Jun 2023 13:07:04 +0100
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Subject: Re: [PATCH v1] misc: fastrpc: Collect driver-remote processor
 transaction logs
Content-Language: en-US
To:     Ekansh Gupta <quic_ekangupt@quicinc.com>,
        linux-arm-msm@vger.kernel.org
Cc:     ekangupt@qti.qualcomm.com, gregkh@linuxfoundation.org,
        linux-kernel@vger.kernel.org, bkumar@qti.qualcomm.com,
        fastrpc.upstream@qti.qualcomm.com
References: <1686070555-11154-1-git-send-email-quic_ekangupt@quicinc.com>
From:   Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
In-Reply-To: <1686070555-11154-1-git-send-email-quic_ekangupt@quicinc.com>
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On 06/06/2023 17:55, Ekansh Gupta wrote:
> Add changes to collect driver-remote processor rpmsg transaction
> logs. These logs will carry payload information for the rpmsg message
> instance. These logs are channel specific and are collected in
> channel context structure.
> 

Can you provide details on who is the actual consumer of this?

Are you planning to dump this data via devcoredumps?

--srini

> These rpmsg transaction logs can help in improving debugability as
> all requests from processes are getting captured in channel context
> structure.
> 
> Signed-off-by: Ekansh Gupta <quic_ekangupt@quicinc.com>
> ---
>   drivers/misc/fastrpc.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 88 insertions(+)
> 
> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
> index 30d4d04..6447cee 100644
> --- a/drivers/misc/fastrpc.c
> +++ b/drivers/misc/fastrpc.c
> @@ -104,6 +104,9 @@
>   
>   #define miscdev_to_fdevice(d) container_of(d, struct fastrpc_device, miscdev)
>   
> +/* Length of glink transaction history to store */
> +#define GLINK_MSG_HISTORY_LEN	(128)
> +
>   static const char *domains[FASTRPC_DEV_MAX] = { "adsp", "mdsp",
>   						"sdsp", "cdsp"};
>   struct fastrpc_phy_page {
> @@ -181,6 +184,28 @@ struct fastrpc_invoke_rsp {
>   	int retval;		/* invoke return value */
>   };
>   
> +struct fastrpc_tx_msg {
> +	struct fastrpc_msg msg;	/* Msg sent to remote subsystem */
> +	int rpmsg_send_err;	/* rpmsg error */
> +	s64 ns;			/* Timestamp (in ns) of msg */
> +};
> +
> +struct fastrpc_rx_msg {
> +	struct fastrpc_invoke_rsp rsp;	/* Response from remote subsystem */
> +	s64 ns;		/* Timestamp (in ns) of response */
> +};
> +
> +struct fastrpc_rpmsg_log {
> +	u32 tx_index;	/* Current index of 'tx_msgs' array */
> +	u32 rx_index;	/* Current index of 'rx_msgs' array */
> +	/* Rolling history of messages sent to remote subsystem */
> +	struct fastrpc_tx_msg tx_msgs[GLINK_MSG_HISTORY_LEN];
> +	/* Rolling history of responses from remote subsystem */
> +	struct fastrpc_rx_msg rx_msgs[GLINK_MSG_HISTORY_LEN];
> +	spinlock_t tx_lock;
> +	spinlock_t rx_lock;
> +};
> +
>   struct fastrpc_buf_overlap {
>   	u64 start;
>   	u64 end;
> @@ -277,6 +302,7 @@ struct fastrpc_channel_ctx {
>   	struct fastrpc_device *fdevice;
>   	struct fastrpc_buf *remote_heap;
>   	struct list_head invoke_interrupted_mmaps;
> +	struct fastrpc_rpmsg_log gmsg_log[FASTRPC_DEV_MAX];
>   	bool secure;
>   	bool unsigned_support;
>   	u64 dma_mask;
> @@ -1097,6 +1123,64 @@ static int fastrpc_put_args(struct fastrpc_invoke_ctx *ctx,
>   	return 0;
>   }
>   
> +static s64 get_timestamp_in_ns(void)
> +{
> +	s64 ns = 0;
> +	struct timespec64 ts;
> +
> +	ktime_get_real_ts64(&ts);
> +	ns = timespec64_to_ns(&ts);
> +	return ns;
> +}
> +
> +static void fastrpc_update_txmsg_buf(struct fastrpc_channel_ctx *chan,
> +				struct fastrpc_msg *msg, int rpmsg_send_err, s64 ns)
> +{
> +	unsigned long flags = 0;
> +	u32 tx_index = 0;
> +	struct fastrpc_tx_msg *tx_msg = NULL;
> +
> +	spin_lock_irqsave(&(chan->gmsg_log[chan->domain_id].tx_lock), flags);
> +
> +	tx_index = chan->gmsg_log[chan->domain_id].tx_index;
> +	tx_msg = &(chan->gmsg_log[chan->domain_id].tx_msgs[tx_index]);
> +
> +	memcpy(&tx_msg->msg, msg, sizeof(struct fastrpc_msg));
> +	tx_msg->rpmsg_send_err = rpmsg_send_err;
> +	tx_msg->ns = ns;
> +
> +	tx_index++;
> +	chan->gmsg_log[chan->domain_id].tx_index =
> +		(tx_index > (GLINK_MSG_HISTORY_LEN - 1)) ? 0 : tx_index;
> +
> +	spin_unlock_irqrestore(&(chan->gmsg_log[chan->domain_id].tx_lock), flags);
> +}
> +
> +static void fastrpc_update_rxmsg_buf(struct fastrpc_channel_ctx *chan,
> +							u64 ctx, int retval, s64 ns)
> +{
> +	unsigned long flags = 0;
> +	u32 rx_index = 0;
> +	struct fastrpc_rx_msg *rx_msg = NULL;
> +	struct fastrpc_invoke_rsp *rsp = NULL;
> +
> +	spin_lock_irqsave(&(chan->gmsg_log[chan->domain_id].rx_lock), flags);
> +
> +	rx_index = chan->gmsg_log[chan->domain_id].rx_index;
> +	rx_msg = &(chan->gmsg_log[chan->domain_id].rx_msgs[rx_index]);
> +	rsp = &rx_msg->rsp;
> +
> +	rsp->ctx = ctx;
> +	rsp->retval = retval;
> +	rx_msg->ns = ns;
> +
> +	rx_index++;
> +	chan->gmsg_log[chan->domain_id].rx_index =
> +		(rx_index > (GLINK_MSG_HISTORY_LEN - 1)) ? 0 : rx_index;
> +
> +	spin_unlock_irqrestore(&(chan->gmsg_log[chan->domain_id].rx_lock), flags);
> +}
> +
>   static int fastrpc_invoke_send(struct fastrpc_session_ctx *sctx,
>   			       struct fastrpc_invoke_ctx *ctx,
>   			       u32 kernel, uint32_t handle)
> @@ -1124,6 +1208,7 @@ static int fastrpc_invoke_send(struct fastrpc_session_ctx *sctx,
>   
>   	if (ret)
>   		fastrpc_context_put(ctx);
> +	fastrpc_update_txmsg_buf(cctx, msg, ret, get_timestamp_in_ns());
>   
>   	return ret;
>   
> @@ -2323,6 +2408,8 @@ static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
>   	INIT_LIST_HEAD(&data->users);
>   	INIT_LIST_HEAD(&data->invoke_interrupted_mmaps);
>   	spin_lock_init(&data->lock);
> +	spin_lock_init(&(data->gmsg_log[data->domain_id].tx_lock));
> +	spin_lock_init(&(data->gmsg_log[data->domain_id].rx_lock));
>   	idr_init(&data->ctx_idr);
>   	data->domain_id = domain_id;
>   	data->rpdev = rpdev;
> @@ -2398,6 +2485,7 @@ static int fastrpc_rpmsg_callback(struct rpmsg_device *rpdev, void *data,
>   
>   	if (len < sizeof(*rsp))
>   		return -EINVAL;
> +	fastrpc_update_rxmsg_buf(cctx, rsp->ctx, rsp->retval, get_timestamp_in_ns());
>   
>   	ctxid = ((rsp->ctx & FASTRPC_CTXID_MASK) >> 4);
>