diff options
Diffstat (limited to 'drivers/usb/gadget/storage_common.c')
| -rw-r--r-- | drivers/usb/gadget/storage_common.c | 33 |
1 files changed, 31 insertions, 2 deletions
diff --git a/drivers/usb/gadget/storage_common.c b/drivers/usb/gadget/storage_common.c index 3ea70d8549ef..9fd379998608 100644 --- a/drivers/usb/gadget/storage_common.c +++ b/drivers/usb/gadget/storage_common.c @@ -52,6 +52,12 @@ * characters rather then a pointer to void. */ +/* + * When USB_GADGET_DEBUG_FILES is defined the module param num_buffers + * sets the number of pipeline buffers (length of the fsg_buffhd array). + * The valid range of num_buffers is: num >= 2 && num <= 4. + */ + #include <linux/usb/storage.h> #include <scsi/scsi.h> @@ -264,8 +270,31 @@ static struct fsg_lun *fsg_lun_from_dev(struct device *dev) #define EP0_BUFSIZE 256 #define DELAYED_STATUS (EP0_BUFSIZE + 999) /* An impossibly large value */ -/* Number of buffers we will use. 2 is enough for double-buffering */ -#define FSG_NUM_BUFFERS 2 +#ifdef CONFIG_USB_GADGET_DEBUG_FILES + +static unsigned int fsg_num_buffers = CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS; +module_param_named(num_buffers, fsg_num_buffers, uint, S_IRUGO); +MODULE_PARM_DESC(num_buffers, "Number of pipeline buffers"); + +#else + +/* + * Number of buffers we will use. + * 2 is usually enough for good buffering pipeline + */ +#define fsg_num_buffers CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS + +#endif /* CONFIG_USB_DEBUG */ + +/* check if fsg_num_buffers is within a valid range */ +static inline int fsg_num_buffers_validate(void) +{ + if (fsg_num_buffers >= 2 && fsg_num_buffers <= 4) + return 0; + pr_err("fsg_num_buffers %u is out of range (%d to %d)\n", + fsg_num_buffers, 2 ,4); + return -EINVAL; +} /* Default size of buffer length. */ #define FSG_BUFLEN ((u32)16384) |