>-----Original Message----- >From: linux-omap-owner@xxxxxxxxxxxxxxx [mailto:linux-omap- >owner@xxxxxxxxxxxxxxx] On Behalf Of Pandita, Vikram >Sent: Friday, April 30, 2010 4:37 PM >To: Kevin Hilman; Tony Lindgren >Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-omap@xxxxxxxxxxxxxxx; Pais, >Allen >Subject: RE: [PATCH 02/11] omap2/3: Fix DEBUG_LL for omap zoom2/3 > > > >>-----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. Reference to that dependency: Commit: 0c8219f0 <snip/start> +/* + * Store the DEBUG_LL uart number into UART1 scratchpad register. + * See also debug-macro.S, and serial.c for related code. + * + * Please note that we currently assume that: + * - UART1 clocks are enabled for register access + * - UART1 scratchpad register can be used + */ +static void set_uart1_scratchpad(unsigned char port) <snip/end> > >> >>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 -- 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
