STRUCT MUSB_PLATFORM_OPS(9)

struct musb_platform_ops(9) 💅

okay so this is the Kernel API Manual page for struct musb_platform_ops, and bestie, it's literally the handshake between the MUSB core and whatever hardware glue layer you're dealing with. Think of it as the group chat where musb_core and your platform-specific code agree on how things get done. 🫶

✨ NAME ✨

struct musb_platform_ops — Operations passed to musb_core by the HW glue layer. that's the whole vibe. the core gets handed this struct and goes "cool, this is how I talk to your weird little hardware." 🎀

🌸 SYNOPSIS 🌸

struct musb_platform_ops {
  #define MUSB_G_NO_SKB_RESERVE   BIT(9);
  #define MUSB_DA8XX              BIT(8);
  #define MUSB_PRESERVE_SESSION   BIT(7);
  #define MUSB_DMA_UX500          BIT(6);
  #define MUSB_DMA_CPPI41         BIT(5);
  #define MUSB_DMA_CPPI           BIT(4);
  #define MUSB_DMA_TUSB_OMAP      BIT(3);
  #define MUSB_DMA_INVENTRA       BIT(2);
  #define MUSB_IN_TUSB            BIT(1);
  #define MUSB_INDEXED_EP         BIT(0);
    u32 quirks;
    int (*init)(struct musb *musb);
    int (*exit)(struct musb *musb);
    void (*enable)(struct musb *musb);
    void (*disable)(struct musb *musb);
    u32 (*ep_offset)(u8 epnum, u16 offset);
    void (*ep_select)(void __iomem *mbase, u8 epnum);
    u16 fifo_mode;
    u32 (*fifo_offset)(u8 epnum);
    u32 (*busctl_offset)(u8 epnum, u16 offset);
    u8 (*readb)(void __iomem *addr, u32 offset);
    void (*writeb)(void __iomem *addr, u32 offset, u8 data);
    u8 (*clearb)(void __iomem *addr, u32 offset);
    u16 (*readw)(void __iomem *addr, u32 offset);
    void (*writew)(void __iomem *addr, u32 offset, u16 data);
    u16 (*clearw)(void __iomem *addr, u32 offset);
    void (*read_fifo)(struct musb_hw_ep *hw_ep, u16 len, u8 *buf);
    void (*write_fifo)(struct musb_hw_ep *hw_ep, u16 len, const u8 *buf);
    u16 (*get_toggle)(struct musb_qh *qh, int is_out);
    u16 (*set_toggle)(struct musb_qh *qh, int is_out, struct urb *urb);
    struct dma_controller * (*dma_init) (struct musb *musb, void __iomem *base);
    void (*dma_exit)(struct dma_controller *c);
    int (*set_mode)(struct musb *musb, u8 mode);
    void (*try_idle)(struct musb *musb, unsigned long timeout);
    int (*recover)(struct musb *musb);
    int (*vbus_status)(struct musb *musb);
    void (*set_vbus)(struct musb *musb, int on);
    void (*pre_root_reset_end)(struct musb *musb);
    void (*post_root_reset_end)(struct musb *musb);
    int (*phy_callback)(enum musb_vbus_id_status status);
    void (*clear_ep_rxintr)(struct musb *musb, int epnum);
};

like, that's a lot of function pointers, and every single one is about to get explained. buckle up. 💖

👑 Members 👑

okay so these are all the members, and I'm giving you the tea on each one, in order, no skipping:

• quirks — flags for platform specific quirks. yes, the field is literally called "quirks." iconic. 🔥
• init — turns on clocks, sets up platform-specific registers, etc. the "wake up babe we're going in" function.
• exit — undoes init. the "ok we're done here, put it all back" function. 🦋
• enable — enable device.
• disable — disable device. (they're a matching set, your honor.)
• ep_offset — returns the end point offset.
• ep_select — selects the specified end point.
• fifo_mode — sets the fifo mode.
• fifo_offset — returns the fifo offset. no cap, it does exactly what it says.
• busctl_offset — ngl, this one is in the struct but the original page doesn't describe it. mystery member energy 🙈 it's between fifo_offset and readb and that's all we're told.
• readb — read 8 bits.
• writeb — write 8 bits.
• clearb — could be clear-on-readb or W1C.
• readw — read 16 bits.
• writew — write 16 bits.
• clearw — could be clear-on-readw or W1C. (notice the pattern? yes, the b/w pair does the same thing at different widths. slay.)
• read_fifo — reads the fifo.
• write_fifo — writes to fifo.
• get_toggle — platform specific get toggle function.
• set_toggle — platform specific set toggle function.
• dma_init — platform specific dma init function.
• dma_exit — platform specific dma exit function.
• set_mode — forcefully changes operating mode. forcefully, bestie. it's not asking. 💅
• try_idle — tries to idle the IP. "tries" is doing a lot of work in that sentence, but that's what it says.
• recover — platform-specific babble recovery. babble!! as in the USB babble condition. this is the "ok calm down" function. 😭
• vbus_status — returns vbus status if possible. if possible. conditional queen.
• set_vbus — forces vbus status.
• pre_root_reset_end — called before the root usb port reset flag gets cleared.
• post_root_reset_end — called after the root usb port reset flag gets cleared. (before/after duo, we love a matched pair 🫶)
• phy_callback — optional callback function for the phy to call. optional! so if you don't need it, don't stress.
• clear_ep_rxintr — this one's also in the struct with no description on this page. another mystery member, but at least the name is self-explanatory-ish. 🙈

🌈 SEE ALSO 🌈

• Kernel file ./drivers/usb/musb/musb_core.h — go read it, it's the whole context, iykyk 💜

and that's the page, bestie! this one came out of ./drivers/usb/musb and it's dated October 2026, so mark your calendar 🗓️✨ go forth and implement your platform ops, you're gonna ate 💅🎀