Re: [PATCH 03/13] scpi: Add legacy send, prepare and handle remote functions
From: Sudeep Holla
Date: Tue Aug 23 2016 - 10:43:32 EST
On 23/08/16 09:15, Neil Armstrong wrote:
On 08/19/2016 06:13 PM, Sudeep Holla wrote:
On 18/08/16 11:10, Neil Armstrong wrote:
In order to support the legacy SCPI procotol, add specific message_send,
prepare_tx and handle_remote functions since the legacy procotol
do not support message queuing and does not store the command word in the
tx_payload data.
Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
---
drivers/firmware/arm_scpi.c | 69 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 69 insertions(+)
diff --git a/drivers/firmware/arm_scpi.c b/drivers/firmware/arm_scpi.c
index 0bb6134..50b1297 100644
--- a/drivers/firmware/arm_scpi.c
+++ b/drivers/firmware/arm_scpi.c
[..]
+static void legacy_scpi_tx_prepare(struct mbox_client *c, void *__msg)
+{
+ struct scpi_chan *ch =
+ container_of(c, struct scpi_chan, cl);
+
+ if (ch->t->tx_buf && ch->t->tx_len)
+ memcpy_toio(ch->tx_payload, ch->t->tx_buf, ch->t->tx_len);
I see that you are not using the list. Any particular reason for that ?
IMO, that *might* help to reuse more code, but I may be wrong. Let's see
Some commands like DVFS take more time compared to simple query type of
commands. Queuing does help there instead of blocking the channel until
the receipt of response.
I'll like to use the list, but, the "cmd" value is not stored in the shared tx
memory, so we cannot recover the original tranfer from reading the tx memory cmd.
Even in the current driver we read the mem->command and search the list
in scpi_process_cmd. Instead *(u32 *)msg gives the command value, no ?
This is why I added a "struct scpi_xfer *t;" in the scpi_chan structure to store
the current transfer.
I don't like that. I am trying to get rid of that.
1. list is not being used
2. scpi_xfer is stashed even though we have only one command in
progress at any time in your case.
+}
+
static int legacy_high_priority_cmds[] = {
LEGACY_SCPI_CMD_GET_CSS_PWR_STATE,
LEGACY_SCPI_CMD_CFG_PWR_STATE_STAT,
@@ -434,6 +461,48 @@ static void put_scpi_xfer(struct scpi_xfer *t, struct scpi_chan *ch)
mutex_unlock(&ch->xfers_lock);
}
+static int legacy_scpi_send_message(u8 cmd, void *tx_buf, unsigned int tx_len,
+ void *rx_buf, unsigned int rx_len)
+{
+ int ret;
+ u8 chan;
+ struct scpi_xfer *msg;
+ struct scpi_chan *scpi_chan;
+
+ chan = legacy_scpi_get_chan(cmd);
+ scpi_chan = scpi_info->channels + chan;
+
+ msg = get_scpi_xfer(scpi_chan);
+ if (!msg)
+ return -ENOMEM;
+
+ mutex_lock(&scpi_chan->xfers_lock);
+
May be you can copy msg->cmd to msg->slot and that may help to reuse
more code or worst-case keep them aligned.
Yes, it could be. But since the msg is not reused bu the tx_prepare and handle_response,
we can pass anything here.
IIUC, we should be able to handle it using msg pte in handle_remote_msg
And for the rockchip case, we must pass an xfer unrelated pointer here since they need
a specially crafted memory structure for the mailbox.
We can consider that when they upstream the driver. Let's not consider
it now.
+ msg->cmd = PACK_LEGACY_SCPI_CMD(cmd, tx_len);
+ msg->tx_buf = tx_buf;
+ msg->tx_len = tx_len;
+ msg->rx_buf = rx_buf;
+ msg->rx_len = rx_len;
+ init_completion(&msg->done);
+ scpi_chan->t = msg;
+
+ ret = mbox_send_message(scpi_chan->chan, &msg->cmd);
If slot is initialized to cmd, then you can pass msg itself above.
Then you can evaluate how much this function deviates from
scpi_send_message and try to re-use.
The function deviates quite a lot since the queing is not used.
You have not given me the reason for not using the list yet.
If the msg ptr is used in scpi_handle_remote_msg, you should be able to
make use of it.
+ if (ret < 0)
+ goto out;
+
+ if (!wait_for_completion_timeout(&msg->done, MAX_RX_TIMEOUT))
+ ret = -ETIMEDOUT;
+ else
+ /* first status word */
+ ret = msg->status;
+out:
+ mutex_unlock(&scpi_chan->xfers_lock);
+
+ put_scpi_xfer(msg, scpi_chan);
+ /* SCPI error codes > 0, translate them to Linux scale*/
+ return ret > 0 ? scpi_to_linux_errno(ret) : ret;
+}
+
static int __scpi_send_message(u8 cmd, void *tx_buf, unsigned int tx_len,
void *rx_buf, unsigned int rx_len, bool extn)
{
[Nit]: Not sure if we need this as a separate patch. It might just
generate warnings, anyways we can merge into one later.
I'll prefer to have functionnaly separate patches for now to clarify the changes.
I'll eventually merge them for the final apply if needed.
Ah OK, then fine.
--
Regards,
Sudeep