Add support for configfs interface so that f_printer can be used as a component of usb gadgets composed with it. Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxx> --- .../ABI/testing/configfs-usb-gadget-printer | 9 ++ Documentation/usb/gadget-testing.txt | 47 ++++++++ drivers/usb/gadget/Kconfig | 13 +++ drivers/usb/gadget/function/f_printer.c | 130 ++++++++++++++++++++- drivers/usb/gadget/function/u_printer.h | 7 ++ 5 files changed, 204 insertions(+), 2 deletions(-) create mode 100644 Documentation/ABI/testing/configfs-usb-gadget-printer diff --git a/Documentation/ABI/testing/configfs-usb-gadget-printer b/Documentation/ABI/testing/configfs-usb-gadget-printer new file mode 100644 index 0000000..6b0714e --- /dev/null +++ b/Documentation/ABI/testing/configfs-usb-gadget-printer @@ -0,0 +1,9 @@ +What: /config/usb-gadget/gadget/functions/printer.name +Date: Apr 2015 +KernelVersion: 4.1 +Description: + The attributes: + + pnp_string - Data to be passed to the host in pnp string + q_len - Number of requests per endpoint + diff --git a/Documentation/usb/gadget-testing.txt b/Documentation/usb/gadget-testing.txt index 076ac7b..f45b2bf 100644 --- a/Documentation/usb/gadget-testing.txt +++ b/Documentation/usb/gadget-testing.txt @@ -19,6 +19,7 @@ provided by gadgets. 16. UAC1 function 17. UAC2 function 18. UVC function +19. PRINTER function 1. ACM function @@ -726,3 +727,49 @@ with these patches: http://www.spinics.net/lists/linux-usb/msg99220.html host: luvcview -f yuv + +19. PRINTER function +==================== + +The function is provided by usb_f_printer.ko module. + +Function-specific configfs interface +------------------------------------ + +The function name to use when creating the function directory is "printer". +The printer function provides these attributes in its function directory: + + pnp_string - Data to be passed to the host in pnp string + q_len - Number of requests per endpoint + +Testing the PRINTER function +---------------------------- + +The most basic testing: + +device: run the gadget +# ls -l /devices/virtual/usb_printer_gadget/ + +should show g_printer<number>. + +If udev is active, then /dev/g_printer<number> should appear automatically. + +host: + +If udev is active, then e.g. /dev/usb/lp0 should appear. + +host->device transmission: + +device: +# cat /dev/g_printer<number> +host: +# cat > /dev/usb/lp0 + +device->host transmission: + +# cat > /dev/g_printer<number> +host: +# cat /dev/usb/lp0 + +More advanced testing can be done with the prn_example +described in Documentation/usb/gadget-printer.txt. diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig index 9d507cf..3bb0e67 100644 --- a/drivers/usb/gadget/Kconfig +++ b/drivers/usb/gadget/Kconfig @@ -437,6 +437,19 @@ config USB_CONFIGFS_F_UVC device. It provides a userspace API to process UVC control requests and stream video data to the host. +config USB_CONFIGFS_F_PRINTER + bool "Printer function" + select USB_F_PRINTER + help + The Printer function channels data between the USB host and a + userspace program driving the print engine. The user space + program reads and writes the device file /dev/g_printer<X> to + receive or send printer data. It can use ioctl calls to + the device file to get or set printer status. + + For more information, see Documentation/usb/gadget_printer.txt + which includes sample code for accessing the device file. + source "drivers/usb/gadget/legacy/Kconfig" endchoice diff --git a/drivers/usb/gadget/function/f_printer.c b/drivers/usb/gadget/function/f_printer.c index 7afe17d..757fcf0 100644 --- a/drivers/usb/gadget/function/f_printer.c +++ b/drivers/usb/gadget/function/f_printer.c @@ -1140,6 +1140,117 @@ static void printer_func_disable(struct usb_function *f) spin_unlock_irqrestore(&dev->lock, flags); } +static inline struct f_printer_opts +*to_f_printer_opts(struct config_item *item) +{ + return container_of(to_config_group(item), struct f_printer_opts, + func_inst.group); +} + +CONFIGFS_ATTR_STRUCT(f_printer_opts); +CONFIGFS_ATTR_OPS(f_printer_opts); + +static void printer_attr_release(struct config_item *item) +{ + struct f_printer_opts *opts = to_f_printer_opts(item); + + usb_put_function_instance(&opts->func_inst); +} + +static struct configfs_item_operations printer_item_ops = { + .release = printer_attr_release, + .show_attribute = f_printer_opts_attr_show, + .store_attribute = f_printer_opts_attr_store, +}; + +static ssize_t f_printer_opts_pnp_string_show(struct f_printer_opts *opts, + char *page) +{ + int result; + + mutex_lock(&opts->lock); + result = strlcpy(page, opts->pnp_string + 2, PNP_STRING_LEN - 2); + mutex_unlock(&opts->lock); + + return result; +} + +static ssize_t f_printer_opts_pnp_string_store(struct f_printer_opts *opts, + const char *page, size_t len) +{ + int result, l; + + mutex_lock(&opts->lock); + result = strlcpy(opts->pnp_string + 2, page, PNP_STRING_LEN - 2); + l = strlen(opts->pnp_string + 2) + 2; + opts->pnp_string[0] = (l >> 8) & 0xFF; + opts->pnp_string[1] = l & 0xFF; + mutex_unlock(&opts->lock); + + return result; +} + +static struct f_printer_opts_attribute f_printer_opts_pnp_string = + __CONFIGFS_ATTR(pnp_string, S_IRUGO | S_IWUSR, + f_printer_opts_pnp_string_show, + f_printer_opts_pnp_string_store); + +static ssize_t f_printer_opts_q_len_show(struct f_printer_opts *opts, + char *page) +{ + int result; + + mutex_lock(&opts->lock); + result = sprintf(page, "%d\n", opts->q_len); + mutex_unlock(&opts->lock); + + return result; +} + +static ssize_t f_printer_opts_q_len_store(struct f_printer_opts *opts, + const char *page, size_t len) +{ + int ret; + u16 num; + + mutex_lock(&opts->lock); + if (opts->refcnt) { + ret = -EBUSY; + goto end; + } + + ret = kstrtou16(page, 0, &num); + if (ret) + goto end; + + if (num > 65535) { + ret = -EINVAL; + goto end; + } + + opts->q_len = (unsigned)num; + ret = len; +end: + mutex_unlock(&opts->lock); + return ret; +} + +static struct f_printer_opts_attribute f_printer_opts_q_len = + __CONFIGFS_ATTR(q_len, S_IRUGO | S_IWUSR, f_printer_opts_q_len_show, + f_printer_opts_q_len_store); + +static struct configfs_attribute *printer_attrs[] = { + &f_printer_opts_pnp_string.attr, + &f_printer_opts_q_len.attr, + NULL, +}; + +static struct config_item_type printer_func_type = { + .ct_item_ops = &printer_item_ops, + .ct_attrs = printer_attrs, + .ct_owner = THIS_MODULE, +}; + static inline int gprinter_get_minor(void) { return ida_simple_get(&printer_ida, 0, 0, GFP_KERNEL); @@ -1180,6 +1291,7 @@ static struct usb_function_instance *gprinter_alloc_inst(void) if (!opts) return ERR_PTR(-ENOMEM); + mutex_init(&opts->lock); opts->func_inst.free_func_inst = gprinter_free_inst; ret = &opts->func_inst; @@ -1201,6 +1313,8 @@ static struct usb_function_instance *gprinter_alloc_inst(void) if (idr_is_empty(&printer_ida.idr)) gprinter_cleanup(); } + config_group_init_type_name(&opts->func_inst.group, "", + &printer_func_type); unlock: mutex_unlock(&printer_ida_lock); @@ -1210,8 +1324,13 @@ unlock: static void gprinter_free(struct usb_function *f) { struct printer_dev *dev = func_to_printer(f); + struct f_printer_opts *opts; + opts = container_of(f->fi, struct f_printer_opts, func_inst); kfree(dev); + mutex_lock(&opts->lock); + --opts->refcnt; + mutex_unlock(&opts->lock); } static void printer_func_unbind(struct usb_configuration *c, @@ -1265,16 +1384,23 @@ static struct usb_function *gprinter_alloc(struct usb_function_instance *fi) opts = container_of(fi, struct f_printer_opts, func_inst); - if (opts->minor >= minors) + mutex_lock(&opts->lock); + if (opts->minor >= minors) { + mutex_unlock(&opts->lock); return ERR_PTR(-ENOENT); + } dev = kzalloc(sizeof(*dev), GFP_KERNEL); - if (!dev) + if (!dev) { + mutex_unlock(&opts->lock); return ERR_PTR(-ENOMEM); + } + ++opts->refcnt; dev->minor = opts->minor; dev->pnp_string = opts->pnp_string; dev->q_len = opts->q_len; + mutex_unlock(&opts->lock); dev->function.name = "printer"; dev->function.bind = printer_func_bind; diff --git a/drivers/usb/gadget/function/u_printer.h b/drivers/usb/gadget/function/u_printer.h index b2338ca..0e2c49d 100644 --- a/drivers/usb/gadget/function/u_printer.h +++ b/drivers/usb/gadget/function/u_printer.h @@ -25,6 +25,13 @@ struct f_printer_opts { int minor; char pnp_string[PNP_STRING_LEN]; unsigned q_len; + + /* + * Protect the data from concurrent access by read/write + * and create symlink/remove symlink + */ + struct mutex lock; + int refcnt; }; #endif /* U_PRINTER_H */ -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
