The Apple CarLife iAP gadget has a descriptor with two alternate settings. The host sends the set_alt request to configure alt_setting 0 or 1, and this is verified by the subsequent get_alt request. This patch implements and sets the get_alt callback. Without the get_alt callback, composite.c abruptly concludes the USB_REQ_GET/SET_INTERFACE request, assuming only one alt setting for the endpoint. Signed-off-by: Hardik Gajjar <hgajjar@xxxxxxxxxxxxxx> --- changes since version 1: - improve commit message to indicate why the get_alt callback is necessary - Link to v1 - https://lore.kernel.org/all/20231124164435.74727-1-hgajjar@xxxxxxxxxxxxxx/ changes since version 2: - Add the limit to allow set up to 2 alt settings. - Link to v2 - https://lore.kernel.org/all/20231201145234.97452-1-hgajjar@xxxxxxxxxxxxxx/ --- drivers/usb/gadget/function/f_fs.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index efe3e3b85769..22200d618184 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -42,6 +42,7 @@ #include "configfs.h" #define FUNCTIONFS_MAGIC 0xa647361 /* Chosen by a honest dice roll ;) */ +#define MAX_ALT_SETTINGS 2 /* Allow up to 2 alt settings to be set. */ /* Reference counter handling */ static void ffs_data_get(struct ffs_data *ffs); @@ -75,6 +76,7 @@ struct ffs_function { short *interfaces_nums; struct usb_function function; + int cur_alt[MAX_CONFIG_INTERFACES]; }; @@ -98,6 +100,7 @@ static int __must_check ffs_func_eps_enable(struct ffs_function *func); static int ffs_func_bind(struct usb_configuration *, struct usb_function *); static int ffs_func_set_alt(struct usb_function *, unsigned, unsigned); +static int ffs_func_get_alt(struct usb_function *f, unsigned int intf); static void ffs_func_disable(struct usb_function *); static int ffs_func_setup(struct usb_function *, const struct usb_ctrlrequest *); @@ -3232,6 +3235,15 @@ static void ffs_reset_work(struct work_struct *work) ffs_data_reset(ffs); } +static int ffs_func_get_alt(struct usb_function *f, + unsigned int interface) +{ + struct ffs_function *func = ffs_func_from_usb(f); + int intf = ffs_func_revmap_intf(func, interface); + + return (intf < 0) ? intf : func->cur_alt[interface]; +} + static int ffs_func_set_alt(struct usb_function *f, unsigned interface, unsigned alt) { @@ -3239,6 +3251,9 @@ static int ffs_func_set_alt(struct usb_function *f, struct ffs_data *ffs = func->ffs; int ret = 0, intf; + if (alt > MAX_ALT_SETTINGS) + return -EINVAL; + if (alt != (unsigned)-1) { intf = ffs_func_revmap_intf(func, interface); if (intf < 0) @@ -3266,8 +3281,10 @@ static int ffs_func_set_alt(struct usb_function *f, ffs->func = func; ret = ffs_func_eps_enable(func); - if (ret >= 0) + if (ret >= 0) { ffs_event_add(ffs, FUNCTIONFS_ENABLE); + func->cur_alt[interface] = alt; + } return ret; } @@ -3574,6 +3591,7 @@ static struct usb_function *ffs_alloc(struct usb_function_instance *fi) func->function.bind = ffs_func_bind; func->function.unbind = ffs_func_unbind; func->function.set_alt = ffs_func_set_alt; + func->function.get_alt = ffs_func_get_alt; func->function.disable = ffs_func_disable; func->function.setup = ffs_func_setup; func->function.req_match = ffs_func_req_match; -- 2.17.1
