Re: [PATCH v2 04/11] soc: qcom: Add Shared Memory Driver

[Georgi Djakov <georgi.djakov@linaro.org>]

Hi Bjorn,
Thank you for this patchset! Some nits and a question below.

On 06/27/2015 12:50 AM, bjorn@kryo.se wrote:
> From: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> 
> This adds the Qualcomm Shared Memory Driver (SMD) providing
> communication channels to remote processors, ontop of SMEM.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> ---
>  drivers/soc/qcom/Kconfig     |    8 +
>  drivers/soc/qcom/Makefile    |    1 +
>  drivers/soc/qcom/smd.c       | 1324 ++++++++++++++++++++++++++++++++++++++++++
>  include/linux/soc/qcom/smd.h |   46 ++
>  4 files changed, 1379 insertions(+)
>  create mode 100644 drivers/soc/qcom/smd.c
>  create mode 100644 include/linux/soc/qcom/smd.h
> 
[...]
> --- /dev/null
> +++ b/drivers/soc/qcom/smd.c
> @@ -0,0 +1,1324 @@
> +/*
> + * Copyright (c) 2015, Sony Mobile Communications AB.
> + * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only version 2 as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/delay.h>

unused?

[...]
> +
> +#define GET_RX_CHANNEL_INFO(channel, param) \
> +	(channel->rx_info_word ? \
> +		channel->rx_info_word->param : \
> +		channel->rx_info->param)
> +
> +#define SET_RX_CHANNEL_INFO(channel, param, value) \
> +	(channel->rx_info_word ? \
> +		(channel->rx_info_word->param = value) : \
> +		(channel->rx_info->param = value))
> +
> +#define GET_TX_CHANNEL_INFO(channel, param) \
> +	(channel->rx_info_word ? \

Maybe this should be tx_info_word?

> +		channel->tx_info_word->param : \
> +		channel->tx_info->param)
> +
> +#define SET_TX_CHANNEL_INFO(channel, param, value) \
> +	(channel->rx_info_word ? \

ditto?

> +		(channel->tx_info_word->param = value) : \
> +		(channel->tx_info->param = value))
> +
[...]
> +	ret = qcom_smem_get(edge->edge_id, smem_fifo_item, &fifo_base, &fifo_size);
> +	if (ret)
> +		goto free_name_and_channel;
> +
> +	/* The channel consist of a rx and tx fifo of equal size */
> +	fifo_size /= 2;
> +
> +	dev_dbg(smd->dev, "new channel '%s' info-size: %d fifo-size: %zu\n",

%zu for info-size?

> +			  name, info_size, fifo_size);
> +

[...]
> +static int __init qcom_smd_init(void)
> +{
> +	int ret;
> +
> +	ret = bus_register(&qcom_smd_bus);
> +	if (ret) {
> +		pr_err("failed to register smd bus: %d\n", ret);
> +		return ret;
> +	}
> +
> +	return platform_driver_register(&qcom_smd_driver);
> +}
> +arch_initcall(qcom_smd_init);
> +
> +static void __exit qcom_smd_exit(void)
> +{
> +	platform_driver_unregister(&qcom_smd_driver);
> +	bus_unregister(&qcom_smd_bus);
> +}
> +module_exit(qcom_smd_exit);
> +
[...]
> +/**
> + * struct qcom_smd_driver - smd driver struct
> + * @driver:	underlying device driver
> + * @probe:	invoked when the smd channel is found
> + * @remove:	invoked when the smd channel is closed
> + * @callback:	invoked when an inbound message is received on the channel,
> + *		should return 0 on success or -EBUSY if the data cannot be
> + *		consumed at this time
> + */
> +struct qcom_smd_driver {
> +	struct device_driver driver;
> +	int (*probe)(struct qcom_smd_device *dev);
> +	void (*remove)(struct qcom_smd_device *dev);
> +	int (*callback)(struct qcom_smd_device *, const void *, size_t);
> +};
> +
> +int qcom_smd_driver_register(struct qcom_smd_driver *drv);
> +void qcom_smd_driver_unregister(struct qcom_smd_driver *drv);
> +
> +#define module_qcom_smd_driver(__smd_driver) \
> +	module_driver(__smd_driver, qcom_smd_driver_register, \
> +		      qcom_smd_driver_unregister)
> +

This comment is mostly related to your RPM over SMD driver patch, as
i have a RPM clock driver based on it. The RPM clock driver registers
some fundamental stuff like XO and i had to hack smd-rpm to probe
earlier, so that most other drivers can initialize. So i was wondering,
what if we register the drivers on the bus earlier? What do you think?

Thanks,
Georgi