| Message ID | 1370000944-19786-2-git-send-email-tushar.behera@linaro.org |
|---|---|
| State | Accepted |
| Headers | show |
On Fri, May 31, 2013 at 05:19:02PM +0530, Tushar Behera wrote: > Printing low-level debug messages make an assumption that the specified > UART port has been preconfigured by the bootloader. Incorrectly > specified UART port results in system getting stalled while printing the > message "Uncompressing Linux... done, booting the kernel" > > This UART port number is specified through S3C_LOWLEVEL_UART_PORT. Since > the UART port might different for different board, it is not possible to > specify it correctly for every board that use a common defconfig file. > > Calling this print subroutine only when DEBUG_LL fixes the problem. By > disabling DEBUG_LL in default config file, we would be able to boot > multiple boards with different default UART ports. > > With this current approach, we miss the print "Uncompressing Linux... > done, booting the kernel." when DEBUG_LL is not defined. > > Signed-off-by: Tushar Behera <tushar.behera@linaro.org> > --- > arch/arm/mach-exynos/include/mach/uncompress.h | 11 ++++++++--- > arch/arm/plat-samsung/include/plat/uncompress.h | 10 +++++++++- > 2 files changed, 17 insertions(+), 4 deletions(-) > > diff --git a/arch/arm/mach-exynos/include/mach/uncompress.h b/arch/arm/mach-exynos/include/mach/uncompress.h > index 2979995..730f69f 100644 > --- a/arch/arm/mach-exynos/include/mach/uncompress.h > +++ b/arch/arm/mach-exynos/include/mach/uncompress.h > @@ -37,11 +37,16 @@ static void arch_detect_cpu(void) > chip_id >>= 20; > chip_id &= 0xf; > > +#ifdef CONFIG_DEBUG_LL > if (chip_id == 0x5) > - uart_base = (volatile u8 *)EXYNOS5_PA_UART + (S3C_UART_OFFSET * CONFIG_S3C_LOWLEVEL_UART_PORT); > + uart_base = (volatile u8 *)EXYNOS5_PA_UART + > + (S3C_UART_OFFSET * CONFIG_S3C_LOWLEVEL_UART_PORT); > else > - uart_base = (volatile u8 *)EXYNOS4_PA_UART + (S3C_UART_OFFSET * CONFIG_S3C_LOWLEVEL_UART_PORT); > - > + uart_base = (volatile u8 *)EXYNOS4_PA_UART + > + (S3C_UART_OFFSET * CONFIG_S3C_LOWLEVEL_UART_PORT); > +#else > + uart_base = NULL; > +#endif You can do: if (!config_enabled(CONFIG_DEBUG_LL)) return; Since uart_base will be set to 0 by being in BSS anyway. -Olof
On 06/01/2013 09:29 AM, Olof Johansson wrote: > On Fri, May 31, 2013 at 05:19:02PM +0530, Tushar Behera wrote: >> Printing low-level debug messages make an assumption that the specified >> UART port has been preconfigured by the bootloader. Incorrectly >> specified UART port results in system getting stalled while printing the >> message "Uncompressing Linux... done, booting the kernel" >> >> This UART port number is specified through S3C_LOWLEVEL_UART_PORT. Since >> the UART port might different for different board, it is not possible to >> specify it correctly for every board that use a common defconfig file. >> >> Calling this print subroutine only when DEBUG_LL fixes the problem. By >> disabling DEBUG_LL in default config file, we would be able to boot >> multiple boards with different default UART ports. >> >> With this current approach, we miss the print "Uncompressing Linux... >> done, booting the kernel." when DEBUG_LL is not defined. >> >> Signed-off-by: Tushar Behera <tushar.behera@linaro.org> >> --- >> arch/arm/mach-exynos/include/mach/uncompress.h | 11 ++++++++--- >> arch/arm/plat-samsung/include/plat/uncompress.h | 10 +++++++++- >> 2 files changed, 17 insertions(+), 4 deletions(-) >> >> diff --git a/arch/arm/mach-exynos/include/mach/uncompress.h b/arch/arm/mach-exynos/include/mach/uncompress.h >> index 2979995..730f69f 100644 >> --- a/arch/arm/mach-exynos/include/mach/uncompress.h >> +++ b/arch/arm/mach-exynos/include/mach/uncompress.h >> @@ -37,11 +37,16 @@ static void arch_detect_cpu(void) >> chip_id >>= 20; >> chip_id &= 0xf; >> >> +#ifdef CONFIG_DEBUG_LL >> if (chip_id == 0x5) >> - uart_base = (volatile u8 *)EXYNOS5_PA_UART + (S3C_UART_OFFSET * CONFIG_S3C_LOWLEVEL_UART_PORT); >> + uart_base = (volatile u8 *)EXYNOS5_PA_UART + >> + (S3C_UART_OFFSET * CONFIG_S3C_LOWLEVEL_UART_PORT); >> else >> - uart_base = (volatile u8 *)EXYNOS4_PA_UART + (S3C_UART_OFFSET * CONFIG_S3C_LOWLEVEL_UART_PORT); >> - >> + uart_base = (volatile u8 *)EXYNOS4_PA_UART + >> + (S3C_UART_OFFSET * CONFIG_S3C_LOWLEVEL_UART_PORT); >> +#else >> + uart_base = NULL; >> +#endif > > You can do: > > if (!config_enabled(CONFIG_DEBUG_LL)) > return; > Thanks for the hint. Or rather, we calculate uart_base unconditionally in mach/uncompress.h and replace check for uart_base with config_enabled(CONFIG_DEBUG_LL) in plat/uncompress.h. That would get rid of all the ifdef's in the mach/uncompress.h files. Let me spin out another version with this change. > Since uart_base will be set to 0 by being in BSS anyway. > > > -Olof >
diff --git a/arch/arm/mach-exynos/include/mach/uncompress.h b/arch/arm/mach-exynos/include/mach/uncompress.h index 2979995..730f69f 100644 --- a/arch/arm/mach-exynos/include/mach/uncompress.h +++ b/arch/arm/mach-exynos/include/mach/uncompress.h @@ -37,11 +37,16 @@ static void arch_detect_cpu(void) chip_id >>= 20; chip_id &= 0xf; +#ifdef CONFIG_DEBUG_LL if (chip_id == 0x5) - uart_base = (volatile u8 *)EXYNOS5_PA_UART + (S3C_UART_OFFSET * CONFIG_S3C_LOWLEVEL_UART_PORT); + uart_base = (volatile u8 *)EXYNOS5_PA_UART + + (S3C_UART_OFFSET * CONFIG_S3C_LOWLEVEL_UART_PORT); else - uart_base = (volatile u8 *)EXYNOS4_PA_UART + (S3C_UART_OFFSET * CONFIG_S3C_LOWLEVEL_UART_PORT); - + uart_base = (volatile u8 *)EXYNOS4_PA_UART + + (S3C_UART_OFFSET * CONFIG_S3C_LOWLEVEL_UART_PORT); +#else + uart_base = NULL; +#endif /* * For preventing FIFO overrun or infinite loop of UART console, * fifo_max should be the minimum fifo size of all of the UART channels diff --git a/arch/arm/plat-samsung/include/plat/uncompress.h b/arch/arm/plat-samsung/include/plat/uncompress.h index 438b248..350032b 100644 --- a/arch/arm/plat-samsung/include/plat/uncompress.h +++ b/arch/arm/plat-samsung/include/plat/uncompress.h @@ -66,6 +66,9 @@ uart_rd(unsigned int reg) static void putc(int ch) { + if (!uart_base) + return; + if (uart_rd(S3C2410_UFCON) & S3C2410_UFCON_FIFOMODE) { int level; @@ -118,7 +121,12 @@ static void arch_decomp_error(const char *x) #ifdef CONFIG_S3C_BOOT_UART_FORCE_FIFO static inline void arch_enable_uart_fifo(void) { - u32 fifocon = uart_rd(S3C2410_UFCON); + u32 fifocon; + + if (!uart_base) + return; + + fifocon = uart_rd(S3C2410_UFCON); if (!(fifocon & S3C2410_UFCON_FIFOMODE)) { fifocon |= S3C2410_UFCON_RESETBOTH;
Printing low-level debug messages make an assumption that the specified UART port has been preconfigured by the bootloader. Incorrectly specified UART port results in system getting stalled while printing the message "Uncompressing Linux... done, booting the kernel" This UART port number is specified through S3C_LOWLEVEL_UART_PORT. Since the UART port might different for different board, it is not possible to specify it correctly for every board that use a common defconfig file. Calling this print subroutine only when DEBUG_LL fixes the problem. By disabling DEBUG_LL in default config file, we would be able to boot multiple boards with different default UART ports. With this current approach, we miss the print "Uncompressing Linux... done, booting the kernel." when DEBUG_LL is not defined. Signed-off-by: Tushar Behera <tushar.behera@linaro.org> --- arch/arm/mach-exynos/include/mach/uncompress.h | 11 ++++++++--- arch/arm/plat-samsung/include/plat/uncompress.h | 10 +++++++++- 2 files changed, 17 insertions(+), 4 deletions(-)