"Pandita, Vikram" <vikram.pandita@xxxxxx> writes: [...] >>>> > --- a/arch/arm/kernel/head.S >>>> > +++ b/arch/arm/kernel/head.S >>>> > @@ -328,6 +328,16 @@ __create_page_tables: >>>> > add r0, r4, #0xd8000000 >> 18 >>>> > str r3, [r0] >>>> > #endif >>>> > +#if defined(CONFIG_MACH_OMAP_ZOOM2) || >>defined(CONFIG_MACH_OMAP_ZOOM3) >>>> > + /* >>>> > + * Zoom2 and Zoom3 have UARTs only on the debug board. >>>> > + * The debug board is connected to the GPMC. >>>> > + */ >>>> > + add r0, r4, #0xfa000000 >> 18 >>>> > + orr r0, r0, #0x00400000 >> 18 @ ZOOM_UART_VIRT >>>> > + orr r3, r7, #0x10000000 @ ZOOM_UART_BASE >>>> > + str r3, [r0] >>>> > +#endif >>>> >>>> I don't see why this part is needed. The same mapping is done using >>>> the .io_pg_offset in the machine description which is done just before >>>> this in head.S >>> >>> That mapping does not cover the GPMC area where this UART is. >> >>Hmm, then shouldn't that be fixed? I understood the .phys_io and and >>.io_pg_offset fields of the mach_desc to be specifically for mapping >>the early UART, and nothing else. > > Here is the problem - with current approach we need two mappings to > happen and the MACHINE_START() code allows for only one via > .io_pg_offset and .phys_io > > Why: > Tony's approach is to pass the information about the debug uart > number from the UART1 Scratchpad register. > > this introduces a dependency that > UART1 registers also be mapped (virt<->phy). > > So for Tony's approach to work, .phys_io/.io_pg_offset continued to > have 0x4800000 based mapping and for external uart zoom3 port, > create this extra mapping. > > So find a better way from compressed.S to pass the uart number to > kernel, and we can solve the problem. Ah, yet another reason to use a memory location instead of UART1 SCR to pass the UART info (c.f. [1]) Kevin [1] http://marc.info/?l=linux-omap&m=127266219130713&w=2 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
