[PATCH v4] drivers: most: add USB adapter driver

[Dan Carpenter]

On Wed, May 27, 2020 at 03:14:28PM +0200, Christian Gromm wrote:
> This patch adds the usb driver source file most_usb.c and
> modifies the Makefile and Kconfig accordingly.
> 
> Signed-off-by: Christian Gromm <christian.gromm at microchip.com>
> ---
> v2:
> Reported-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
>         - don't remove usb driver from staging area
>         - don't touch staging/most/Kconfig
>         - remove subdirectory for USB driver and put source file into
>           drivers/most
> v3:
>         - submitted fixes found during code audit to staging version
>           first to be able to resend single patch that adds the driver
> v4:
> Reported-by: Dan Carpenter <dan.carpenter at oracle.com>
> 	
>         submitted patch set that fixes issues found during code audit
> 	to staging version first to be able to resend single patch that
> 	adds the driver. The patch series included:
> 
> 	- use function sysfs_streq
> 	- add missing put_device calls
> 	- use correct error codes
> 	- replace code to calculate array index
> 	- don't use error path to exit function on success
> 	- move allocation of URB out of critical section
> 	- return 0 instead of variable
> 	- change return value of function drci_rd_reg
> 	- don't use expressions that might fail in a declaration
> 	- change order of function parameters

Thanks for doing this.  I'm sorry that I am behind on reviewing code so
I hadn't gotten to that patchset yet.

> +static unsigned int get_stream_frame_size(struct device *dev,
> +					  struct most_channel_config *cfg)
> +{
> +	unsigned int frame_size;
> +	unsigned int sub_size = cfg->subbuffer_size;
> +
> +	if (!sub_size) {
> +		dev_warn(dev, "Misconfig: Subbuffer size zero.\n");
> +		return 0;
> +	}
> +	switch (cfg->data_type) {
> +	case MOST_CH_ISOC:
> +		frame_size = AV_PACKETS_PER_XACT * sub_size;
> +		break;
> +	case MOST_CH_SYNC:
> +		if (cfg->packets_per_xact == 0) {
> +			dev_warn(dev, "Misconfig: Packets per XACT zero\n");
> +			frame_size = 0;
> +		} else if (cfg->packets_per_xact == 0xFF) {
> +			frame_size = (USB_MTU / sub_size) * sub_size;
> +		} else {
> +			frame_size = cfg->packets_per_xact * sub_size;
> +		}
> +		break;
> +	default:
> +		dev_warn(dev, "Query frame size of non-streaming channel\n");
> +		break;

frame_size isn't initialized on this path.

> +	}
> +	return frame_size;
> +}

regards,
dan carpenter