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SubjectRe: [PATCH v7 06/13] slimbus: Add messaging APIs to slimbus framework
On Wed, Nov 15, 2017 at 02:10:36PM +0000, srinivas.kandagatla@linaro.org wrote:

> +void slim_msg_response(struct slim_controller *ctrl, u8 *reply, u8 tid, u8 len)
> +{
> + struct slim_msg_txn *txn;
> + struct slim_val_inf *msg;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&ctrl->txn_lock, flags);

Do you need this to be a _irqsave variant? What is the context of io
transfers in this case

> +/**
> + * slim_do_transfer() - Process a slimbus-messaging transaction
> + *
> + * @ctrl: Controller handle
> + * @txn: Transaction to be sent over SLIMbus
> + *
> + * Called by controller to transmit messaging transactions not dealing with
> + * Interface/Value elements. (e.g. transmittting a message to assign logical
> + * address to a slave device
> + *
> + * Return: -ETIMEDOUT: If transmission of this message timed out
> + * (e.g. due to bus lines not being clocked or driven by controller)
> + * -ENOTCONN: If the transmitted message was not ACKed by destination
> + * device.

I am preferring ENODATA in SDW for this case, as Slaves didnt respond or
ACK.

ENOTCONN is defined as /* Transport endpoint is not connected */ which is
not the case here, connected yes but not responded.

> +static int slim_val_inf_sanity(struct slim_controller *ctrl,
> + struct slim_val_inf *msg, u8 mc)
> +{
> + if (!msg || msg->num_bytes > 16 ||
> + (msg->start_offset + msg->num_bytes) > 0xC00)
> + goto reterr;
> + switch (mc) {
> + case SLIM_MSG_MC_REQUEST_VALUE:
> + case SLIM_MSG_MC_REQUEST_INFORMATION:
> + if (msg->rbuf != NULL)
> + return 0;
> + break;

empty line here and after each break make it look better

> + case SLIM_MSG_MC_CHANGE_VALUE:
> + case SLIM_MSG_MC_CLEAR_INFORMATION:
> + if (msg->wbuf != NULL)
> + return 0;
> + break;
> + case SLIM_MSG_MC_REQUEST_CHANGE_VALUE:
> + case SLIM_MSG_MC_REQUEST_CLEAR_INFORMATION:
> + if (msg->rbuf != NULL && msg->wbuf != NULL)
> + return 0;
> + break;
> + default:
> + break;

this seems superflous and we can just fall thru to error below.

> + }
> +reterr:
> + dev_err(ctrl->dev, "Sanity check failed:msg:offset:0x%x, mc:%d\n",
> + msg->start_offset, mc);
> + return -EINVAL;

...

> +static int slim_xfer_msg(struct slim_controller *ctrl,
> + struct slim_device *sbdev,
> + struct slim_val_inf *msg, u8 mc)
> +{
> + DEFINE_SLIM_LDEST_TXN(txn_stack, mc, 6, sbdev->laddr, msg);
> + struct slim_msg_txn *txn = &txn_stack;
> + int ret;
> + u16 sl;
> +
> + ret = slim_val_inf_sanity(ctrl, msg, mc);
> + if (ret)
> + return ret;
> +
> + sl = slim_slicesize(msg->num_bytes);
> +
> + dev_dbg(ctrl->dev, "SB xfer msg:os:%x, len:%d, MC:%x, sl:%x\n",
> + msg->start_offset, msg->num_bytes, mc, sl);

better to add tracing support for these debug prints

> +
> + txn->ec = ((sl | (1 << 3)) | ((msg->start_offset & 0xFFF) << 4));
> +
> + switch (mc) {
> + case SLIM_MSG_MC_REQUEST_CHANGE_VALUE:
> + case SLIM_MSG_MC_CHANGE_VALUE:
> + case SLIM_MSG_MC_REQUEST_CLEAR_INFORMATION:
> + case SLIM_MSG_MC_CLEAR_INFORMATION:
> + txn->rl += msg->num_bytes;
> + default:
> + break;
> + }
> +
> + if (slim_tid_txn(txn->mt, txn->mc))
> + txn->rl++;
> +
> + return slim_do_transfer(ctrl, txn);
> +}
> +
> +/**
> + * slim_request_val_element() - request value element
> + *
> + * @sb: client handle requesting elemental message reads, writes.
> + * @msg: Input structure for start-offset, number of bytes to read.
> + * context: can sleep
> + *
> + * Return: -EINVAL: Invalid parameters
> + * -ETIMEDOUT: If transmission of this message timed out (e.g. due to
> + * bus lines not being clocked or driven by controller)
> + * -ENOTCONN: If the transmitted message was not ACKed by the device.
> + */
> +int slim_request_val_element(struct slim_device *sb,
> + struct slim_val_inf *msg)
> +{
> + struct slim_controller *ctrl = sb->ctrl;
> +
> + if (!ctrl)
> + return -EINVAL;
> +
> + return slim_xfer_msg(ctrl, sb, msg, SLIM_MSG_MC_REQUEST_VALUE);
> +}
> +EXPORT_SYMBOL_GPL(slim_request_val_element);
> +
> +/**
> + * slim_request_inf_element() - Request a info element
> + *
> + * @sb: client handle requesting elemental message reads.
> + * @msg: Input structure for start-offset, number of bytes to read
> + * wbuf will contain information element(s) bit masks to be cleared.
> + * rbuf will return what the information element value was
> + */
> +int slim_request_inf_element(struct slim_device *sb,
> + struct slim_val_inf *msg)
> +{
> + struct slim_controller *ctrl = sb->ctrl;
> +
> + if (!ctrl)
> + return -EINVAL;
> +
> + return slim_xfer_msg(ctrl, sb, msg, SLIM_MSG_MC_REQUEST_INFORMATION);
> +}
> +EXPORT_SYMBOL_GPL(slim_request_inf_element);
> +
> +/**
> + * slim_change_val_element: change a given value element
> + *
> + * @sb: client handle requesting elemental message reads, writes.
> + * @msg: Input structure for start-offset, number of bytes to write.
> + * context: can sleep
> + *
> + * Return:
> + * -EINVAL: Invalid parameters
> + * -ETIMEDOUT: If transmission of this message timed out (e.g. due to
> + * bus lines not being clocked or driven by controller)
> + * -ENOTCONN: If the transmitted message was not ACKed by the device.
> + */
> +int slim_change_val_element(struct slim_device *sb, struct slim_val_inf *msg)
> +{
> + struct slim_controller *ctrl = sb->ctrl;
> +
> + if (!ctrl)
> + return -EINVAL;
> +
> + return slim_xfer_msg(ctrl, sb, msg, SLIM_MSG_MC_CHANGE_VALUE);
> +}
> +EXPORT_SYMBOL_GPL(slim_change_val_element);
> +
> +/**
> + * slim_clear_inf_element() - Clear info element
> + *
> + * @sb: client handle requesting elemental message reads, writes.
> + * @msg: Input structure for start-offset, number of bytes to read
> + * wbuf will contain information element(s) bit masks to be cleared.
> + * rbuf will return what the information element value was
> + */
> +int slim_clear_inf_element(struct slim_device *sb, struct slim_val_inf *msg)
> +{
> + struct slim_controller *ctrl = sb->ctrl;
> +
> + if (!ctrl)
> + return -EINVAL;
> +
> + return slim_xfer_msg(ctrl, sb, msg, SLIM_MSG_MC_CLEAR_INFORMATION);
> +}
> +EXPORT_SYMBOL_GPL(slim_clear_inf_element);
> +
> +/**
> + * slim_request_val_element() - change and request a given value element
> + *
> + * @sb: client handle requesting elemental message reads, writes.
> + * @msg: Input structure for start-offset, number of bytes to write.
> + * context: can sleep
> + *
> + * Return:
> + * -EINVAL: Invalid parameters
> + * -ETIMEDOUT: If transmission of this message timed out (e.g. due to
> + * bus lines not being clocked or driven by controller)
> + * -ENOTCONN: If the transmitted message was not ACKed by the device.
> + */
> +int slim_request_change_val_element(struct slim_device *sb,
> + struct slim_val_inf *msg)
> +{
> + struct slim_controller *ctrl = sb->ctrl;
> +
> + if (!ctrl)
> + return -EINVAL;
> +
> + return slim_xfer_msg(ctrl, sb, msg, SLIM_MSG_MC_REQUEST_CHANGE_VALUE);
> +}
> +EXPORT_SYMBOL_GPL(slim_request_change_val_element);

looking at this, does it really help to have different APIs for SLIM_MSG_XXX
why not slim_xfer_msg() be an exported one..

> +int slim_write(struct slim_device *sdev, u32 addr, size_t count, u8 *val)
> +{
> + struct slim_val_inf msg;
> + int ret;
> +
> + slim_fill_msg(&msg, addr, count, val, NULL);
> + ret = slim_change_val_element(sdev, &msg);

return slim_change_val_element()

> +
> + return ret;
> +
> +}

...

> +/* Destination type Values */
> +#define SLIM_MSG_DEST_LOGICALADDR 0
> +#define SLIM_MSG_DEST_ENUMADDR 1
> +#define SLIM_MSG_DEST_BROADCAST 3
^^^
why tab here


--
~Vinod
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