USB: gadget: g_fs: code cleanup

This commit cleans the g_fs gadget hopefully making it more
readable.  This is achieved by usage of the usb_string_ids_tab()
function for batch string IDs registration as well as
generalising configuration so that a single routine is
used to add each configuration and bind interfaces.  As an
effect, the code is shorter and has fewer #ifdefs.

Moreover, in some circumstances previous code #defined
CONFIG_USB_FUNCTIONFS_GENERIC macro to prevent a situation
where gadget with no configurations is built.  This code removes
the #define form source code and achieves the same effect using
select in Kconfig.

This patch also changes wording and names of the Kconfig options.

Signed-off-by: Michal Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 60 insertions, 137 deletions

diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 027f61b1f3d8..dd3b25101858 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -714,6 +714,7 @@ config USB_GADGETFS
 config USB_FUNCTIONFS
         tristate "Function Filesystem (EXPERIMENTAL)"
         depends on EXPERIMENTAL
+        select USB_FUNCTIONFS_GENERIC if !(USB_FUNCTIONFS_ETH || USB_FUNCTIONFS_RNDIS)
         help
           The Function Filesystem (FunctioFS) lets one create USB
           composite functions in user space in the same way as GadgetFS
@@ -722,31 +723,31 @@ config USB_FUNCTIONFS
           implemented in kernel space (for instance Ethernet, serial or
           mass storage) and other are implemented in user space.
 
+          If you say "y" or "m" here you will be able what kind of
+          configurations the gadget will provide.
+
           Say "y" to link the driver statically, or "m" to build
           a dynamically linked module called "g_ffs".
 
 config USB_FUNCTIONFS_ETH
-        bool "Include CDC ECM (Ethernet) function"
+        bool "Include configuration with CDC ECM (Ethernet)"
         depends on USB_FUNCTIONFS && NET
         help
-          Include an CDC ECM (Ethernet) funcion in the CDC ECM (Funcion)
-          Filesystem.  If you also say "y" to the RNDIS query below the
-          gadget will have two configurations.
+          Include a configuration with CDC ECM funcion (Ethernet) and the
+          Funcion Filesystem.
 
 config USB_FUNCTIONFS_RNDIS
-        bool "Include RNDIS (Ethernet) function"
+        bool "Include configuration with RNDIS (Ethernet)"
         depends on USB_FUNCTIONFS && NET
         help
-          Include an RNDIS (Ethernet) funcion in the Funcion Filesystem.
-          If you also say "y" to the CDC ECM query above the gadget will
-          have two configurations.
+          Include a configuration with RNDIS funcion (Ethernet) and the Filesystem.
 
 config USB_FUNCTIONFS_GENERIC
         bool "Include 'pure' configuration"
-        depends on USB_FUNCTIONFS && (USB_FUNCTIONFS_ETH || USB_FUNCTIONFS_RNDIS)
+        depends on USB_FUNCTIONFS
         help
-          Include a configuration with FunctionFS and no Ethernet
-          configuration.
+          Include a configuration with the Function Filesystem alone with
+          no Ethernet interface.
 
 config USB_FILE_STORAGE
         tristate "File-backed Storage Gadget"
diff --git a/drivers/usb/gadget/g_ffs.c b/drivers/usb/gadget/g_ffs.c
index da3a9e403497..a9474f8d5325 100644
--- a/drivers/usb/gadget/g_ffs.c
+++ b/drivers/usb/gadget/g_ffs.c
@@ -32,12 +32,13 @@
 #  include "u_ether.c"
 
 static u8 gfs_hostaddr[ETH_ALEN];
-#else
-#  if !defined CONFIG_USB_FUNCTIONFS_GENERIC
-#    define CONFIG_USB_FUNCTIONFS_GENERIC
+#  ifdef CONFIG_USB_FUNCTIONFS_ETH
+static int eth_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN]);
 #  endif
+#else
 #  define gether_cleanup() do { } while (0)
 #  define gether_setup(gadget, hostaddr)   ((int)0)
+#  define gfs_hostaddr NULL
 #endif
 
 #include "f_fs.c"
@@ -107,15 +108,7 @@ static const struct usb_descriptor_header *gfs_otg_desc[] = {
 enum {
         GFS_STRING_MANUFACTURER_IDX,
         GFS_STRING_PRODUCT_IDX,
-#ifdef CONFIG_USB_FUNCTIONFS_RNDIS
-        GFS_STRING_RNDIS_CONFIG_IDX,
-#endif
-#ifdef CONFIG_USB_FUNCTIONFS_ETH
-        GFS_STRING_ECM_CONFIG_IDX,
-#endif
-#ifdef CONFIG_USB_FUNCTIONFS_GENERIC
-        GFS_STRING_GENERIC_CONFIG_IDX,
-#endif
+        GFS_STRING_FIRST_CONFIG_IDX,
 };
 
 static       char gfs_manufacturer[50];
@@ -126,13 +119,13 @@ static struct usb_string gfs_strings[] = {
         [GFS_STRING_MANUFACTURER_IDX].s = gfs_manufacturer,
         [GFS_STRING_PRODUCT_IDX].s = gfs_driver_desc,
 #ifdef CONFIG_USB_FUNCTIONFS_RNDIS
-        [GFS_STRING_RNDIS_CONFIG_IDX].s = "FunctionFS + RNDIS",
+        { .s = "FunctionFS + RNDIS" },
 #endif
 #ifdef CONFIG_USB_FUNCTIONFS_ETH
-        [GFS_STRING_ECM_CONFIG_IDX].s = "FunctionFS + ECM",
+        { .s = "FunctionFS + ECM" },
 #endif
 #ifdef CONFIG_USB_FUNCTIONFS_GENERIC
-        [GFS_STRING_GENERIC_CONFIG_IDX].s = "FunctionFS",
+        { .s = "FunctionFS" },
 #endif
         {  } /* end of list */
 };
@@ -146,59 +139,33 @@ static struct usb_gadget_strings *gfs_dev_strings[] = {
 };
 
 
+
+struct gfs_configuration {
+        struct usb_configuration c;
+        int (*eth)(struct usb_configuration *c, u8 *ethaddr);
+} gfs_configurations[] = {
 #ifdef CONFIG_USB_FUNCTIONFS_RNDIS
-static int gfs_do_rndis_config(struct usb_configuration *c);
-
-static struct usb_configuration gfs_rndis_config_driver = {
-        .label                  = "FunctionFS + RNDIS",
-        .bind                   = gfs_do_rndis_config,
-        .bConfigurationValue    = 1,
-        /* .iConfiguration      = DYNAMIC */
-        .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
-};
-#  define gfs_add_rndis_config(cdev) \
-        usb_add_config(cdev, &gfs_rndis_config_driver)
-#else
-#  define gfs_add_rndis_config(cdev) 0
+        {
+                .eth            = rndis_bind_config,
+        },
 #endif
 
-
 #ifdef CONFIG_USB_FUNCTIONFS_ETH
-static int gfs_do_ecm_config(struct usb_configuration *c);
-
-static struct usb_configuration gfs_ecm_config_driver = {
-        .label                  = "FunctionFS + ECM",
-        .bind                   = gfs_do_ecm_config,
-        .bConfigurationValue    = 1,
-        /* .iConfiguration      = DYNAMIC */
-        .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
-};
-#  define gfs_add_ecm_config(cdev) \
-        usb_add_config(cdev, &gfs_ecm_config_driver)
-#else
-#  define gfs_add_ecm_config(cdev) 0
+        {
+                .eth            = eth_bind_config,
+        },
 #endif
 
-
 #ifdef CONFIG_USB_FUNCTIONFS_GENERIC
-static int gfs_do_generic_config(struct usb_configuration *c);
-
-static struct usb_configuration gfs_generic_config_driver = {
-        .label                  = "FunctionFS",
-        .bind                   = gfs_do_generic_config,
-        .bConfigurationValue    = 2,
-        /* .iConfiguration      = DYNAMIC */
-        .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
-};
-#  define gfs_add_generic_config(cdev) \
-        usb_add_config(cdev, &gfs_generic_config_driver)
-#else
-#  define gfs_add_generic_config(cdev) 0
+        {
+        },
 #endif
+};
 
 
 static int gfs_bind(struct usb_composite_dev *cdev);
 static int gfs_unbind(struct usb_composite_dev *cdev);
+static int gfs_do_config(struct usb_configuration *c);
 
 static struct usb_composite_driver gfs_driver = {
         .name           = gfs_short_name,
@@ -267,7 +234,7 @@ static int functionfs_check_dev_callback(const char *dev_name)
 
 static int gfs_bind(struct usb_composite_dev *cdev)
 {
-        int ret;
+        int ret, i;
 
         ENTER();
 
@@ -284,57 +251,32 @@ static int gfs_bind(struct usb_composite_dev *cdev)
         snprintf(gfs_manufacturer, sizeof gfs_manufacturer, "%s %s with %s",
                  init_utsname()->sysname, init_utsname()->release,
                  cdev->gadget->name);
-        ret = usb_string_id(cdev);
-        if (unlikely(ret < 0))
-                goto error;
-        gfs_strings[GFS_STRING_MANUFACTURER_IDX].id = ret;
-        gfs_dev_desc.iManufacturer = ret;
-
-        ret = usb_string_id(cdev);
-        if (unlikely(ret < 0))
-                goto error;
-        gfs_strings[GFS_STRING_PRODUCT_IDX].id = ret;
-        gfs_dev_desc.iProduct = ret;
-
-#ifdef CONFIG_USB_FUNCTIONFS_RNDIS
-        ret = usb_string_id(cdev);
-        if (unlikely(ret < 0))
-                goto error;
-        gfs_strings[GFS_STRING_RNDIS_CONFIG_IDX].id = ret;
-        gfs_rndis_config_driver.iConfiguration = ret;
-#endif
 
-#ifdef CONFIG_USB_FUNCTIONFS_ETH
-        ret = usb_string_id(cdev);
+        ret = usb_string_ids_tab(cdev, gfs_strings);
         if (unlikely(ret < 0))
                 goto error;
-        gfs_strings[GFS_STRING_ECM_CONFIG_IDX].id = ret;
-        gfs_ecm_config_driver.iConfiguration = ret;
-#endif
 
-#ifdef CONFIG_USB_FUNCTIONFS_GENERIC
-        ret = usb_string_id(cdev);
-        if (unlikely(ret < 0))
-                goto error;
-        gfs_strings[GFS_STRING_GENERIC_CONFIG_IDX].id = ret;
-        gfs_generic_config_driver.iConfiguration = ret;
-#endif
+        gfs_dev_desc.iManufacturer = gfs_strings[GFS_STRING_MANUFACTURER_IDX].id;
+        gfs_dev_desc.iProduct      = gfs_strings[GFS_STRING_PRODUCT_IDX].id;
 
         ret = functionfs_bind(gfs_ffs_data, cdev);
         if (unlikely(ret < 0))
                 goto error;
 
-        ret = gfs_add_rndis_config(cdev);
-        if (unlikely(ret < 0))
-                goto error_unbind;
+        for (i = 0; i < ARRAY_SIZE(gfs_configurations); ++i) {
+                struct gfs_configuration *c = gfs_configurations + i;
 
-        ret = gfs_add_ecm_config(cdev);
-        if (unlikely(ret < 0))
-                goto error_unbind;
+                ret = GFS_STRING_FIRST_CONFIG_IDX + i;
+                c->c.label                      = gfs_strings[ret].s;
+                c->c.iConfiguration             = gfs_strings[ret].id;
+                c->c.bind                       = gfs_do_config;
+                c->c.bConfigurationValue        = 1 + i;
+                c->c.bmAttributes               = USB_CONFIG_ATT_SELFPOWER;
 
-        ret = gfs_add_generic_config(cdev);
-        if (unlikely(ret < 0))
-                goto error_unbind;
+                ret = usb_add_config(cdev, &c->c);
+                if (unlikely(ret < 0))
+                        goto error_unbind;
+        }
 
         return 0;
 
@@ -368,10 +310,10 @@ static int gfs_unbind(struct usb_composite_dev *cdev)
 }
 
 
-static int __gfs_do_config(struct usb_configuration *c,
-                           int (*eth)(struct usb_configuration *c, u8 *ethaddr),
-                           u8 *ethaddr)
+static int gfs_do_config(struct usb_configuration *c)
 {
+        struct gfs_configuration *gc =
+                container_of(c, struct gfs_configuration, c);
         int ret;
 
         if (WARN_ON(!gfs_ffs_data))
@@ -382,8 +324,8 @@ static int __gfs_do_config(struct usb_configuration *c,
                 c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
         }
 
-        if (eth) {
-                ret = eth(c, ethaddr);
+        if (gc->eth) {
+                ret = gc->eth(c, gfs_hostaddr);
                 if (unlikely(ret < 0))
                         return ret;
         }
@@ -406,32 +348,12 @@ static int __gfs_do_config(struct usb_configuration *c,
         return 0;
 }
 
-#ifdef CONFIG_USB_FUNCTIONFS_RNDIS
-static int gfs_do_rndis_config(struct usb_configuration *c)
-{
-        ENTER();
-
-        return __gfs_do_config(c, rndis_bind_config, gfs_hostaddr);
-}
-#endif
 
 #ifdef CONFIG_USB_FUNCTIONFS_ETH
-static int gfs_do_ecm_config(struct usb_configuration *c)
-{
-        ENTER();
-
-        return __gfs_do_config(c,
-                               can_support_ecm(c->cdev->gadget)
-                             ? ecm_bind_config : geth_bind_config,
-                               gfs_hostaddr);
-}
-#endif
-
-#ifdef CONFIG_USB_FUNCTIONFS_GENERIC
-static int gfs_do_generic_config(struct usb_configuration *c)
+static int eth_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN])
 {
-        ENTER();
-
-        return __gfs_do_config(c, NULL, NULL);
+        return can_support_ecm(c->cdev->gadget)
+                ? ecm_bind_config(c, ethaddr)
+                : geth_bind_config(c, ethaddr);
 }
 #endif