On Fri, May 1, 2020 at 4:42 AM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> On Thu, 30 Apr 2020, Arnd Bergmann wrote:
>
> No, they don't.
> > /* PORTSC: offset 0x44 */
> > - u32 port_status[0]; /* up to N_PORTS */
> > + union {
> > + u32 port_status[9]; /* up to N_PORTS */
>
> This array can have up to 15 elements, meaning that it can extend out
> to offset 0x80.
Ok, thanks for the clarification!
> > /* EHCI 1.1 addendum */
> > #define PORTSC_SUSPEND_STS_ACK 0
> > #define PORTSC_SUSPEND_STS_NYET 1
> > @@ -165,7 +166,8 @@ struct ehci_regs {
> > #define PORT_CONNECT (1<<0) /* device connected */
> > #define PORT_RWC_BITS (PORT_CSC | PORT_PEC | PORT_OCC)
> >
> > - u32 reserved3[9];
> > + u32 reserved3[9];
> > + };
> >
> > /* USBMODE: offset 0x68 */
> > u32 usbmode; /* USB Device mode */
>
> As you see, this next field actually lies inside the preceding array.
> It's not a real conflict; any hardware which supports the usbmode field
> uses only the first element of the port_status array.
>
> I don't know how you want to handle this. Doing
>
> #define usbmode port_status[9]
>
> doesn't seem like a very good approach, but I can't think of anything
> better at the moment. Maybe just set the array size to 9, as you did,
> but with a comment explaining what's really going on.
The easiest change would be to use an anonymous struct like this
/* PORTSC: offset 0x44 */
union {
u32 port_status[15]; /* up to N_PORTS */
/* EHCI 1.1 addendum */
#define PORTSC_SUSPEND_STS_ACK 0
...
#define PORT_RWC_BITS (PORT_CSC | PORT_PEC | PORT_OCC)
struct {
u32 reserved3[9];
/* USBMODE: offset 0x68 */
u32 usbmode; /* USB Device mode */
#define USBMODE_SDIS (1<<3) /* Stream disable */
#define USBMODE_BE (1<<2) /* BE/LE endianness select */
#define USBMODE_CM_HC (3<<0) /* host controller mode */
#define USBMODE_CM_IDLE (0<<0) /* idle state */
u32 reserved4[5];
};
};
u32 reserved5;
It doesn't really improve readability, but it should correctly
reflect the layout as you described it.
Arnd
