>-----Original Message----- >From: Kevin Hilman [mailto:khilman@xxxxxxxxxxxxxxxxxxx] >Sent: Friday, April 30, 2010 4:21 PM >To: Tony Lindgren >Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; Pandita, Vikram; linux- >omap@xxxxxxxxxxxxxxx; Pais, Allen >Subject: Re: [PATCH 02/11] omap2/3: Fix DEBUG_LL for omap zoom2/3 > >Tony Lindgren <tony@xxxxxxxxxxx> writes: > >> * Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx> [100430 13:50]: >>> Tony Lindgren <tony@xxxxxxxxxxx> writes: >>> >>> > Zoom2 and 3 have UARTs only on the external debug board. >>> > GPMC needs to be mapped early to use it for DEBUG_LL. >>> > >>> > Additionally, 0xfb000000 overlaps with other areas, so >>> > use 0xfa400000 for the virtual address instead. >>> > >>> > Note that with the pending serial.c patches you need to >>> > set console=ttyS0,115200n8 as it will be the only UART >>> > mapped. To use DEBUG_LL, you need to pass also earlyprintk >>> > in cmdline. >>> > >>> > Cc: Allen Pais <allen.pais@xxxxxx> >>> > Cc: Vikram Pandita <vikram.pandita@xxxxxx> >>> > Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx> >>> > --- >>> > arch/arm/kernel/head.S | 10 ++++++++++ >>> > arch/arm/mach-omap2/board-zoom-debugboard.c | 2 +- >>> > arch/arm/mach-omap2/include/mach/debug-macro.S | 4 ++-- >>> > arch/arm/mach-omap2/io.c | 9 +++++++++ >>> > arch/arm/plat-omap/include/plat/serial.h | 2 +- >>> > 5 files changed, 23 insertions(+), 4 deletions(-) >>> > >>> > diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S >>> > index eb62bf9..fd870e1 100644 >>> > --- 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. > >Kevin > -- 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
