| Message ID | CAKew6eX5JperTq4Quo_mPR8L638_VfqTnDvz_kmmTjDNNykYOg@mail.gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tuesday 23 of July 2013 13:04:58 Yadwinder Singh Brar wrote: > On Mon, Jul 22, 2013 at 6:37 PM, Tomasz Figa <t.figa@samsung.com> wrote: > > On Monday 22 of July 2013 06:23:06 Thomas Abraham wrote: > >> On 13 July 2013 04:57, Yadwinder Singh Brar <yadi.brar@samsung.com> > > > > wrote: > >> > Presently, using exynos_defconfig with CONFIG_DEBUG_LL and > >> > CONFIG_EARLY_PRINTK on, kernel is not booting, we are getting > >> > following: > >> > > >> > [ 0.000000] ------------[ cut here ]------------ > >> > [ 0.000000] kernel BUG at mm/vmalloc.c:1134! > >> > [ 0.000000] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM > >> > [ 0.000000] Modules linked in: > >> > [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 3.11.0-rc1 > >> > #633 > >> > [ 0.000000] task: c052ec48 ti: c0524000 task.ti: c0524000 > >> > [ 0.000000] PC is at vm_area_add_early+0x54/0x94 > >> > [ 0.000000] LR is at add_static_vm_early+0xc/0x60 > >> > > >> > Its because iotable_init tries to map UART again which is already > >> > mapped by debug_ll_io_init() call in exynos_init_io() within same > >> > virtal address range as requested later. > >> > >> debug_ll_io_init ioremaps debug uart address space with 4KB size > >> whereas the exynos_init_io() function ioremaps a single 512KB memory > >> size for all the four uart ports which envelops the mapping created > >> by > >> debug_ll_io_init. This is caught as a kernel bug. > > > > Right. > > > >> > This issue seems to be occured after : > >> > commit ee4de5d99aeac44f4507b7538b2b3faedc5205b9 > >> > ARM: 7781/1: mmu: Add debug_ll_io_init() mappings to early mappings > >> > > >> > This patch moves S3C_UART iodesc(in iodesc_list) inside > >> > CONFIG_DEBUG_LL > >> > check. > >> > >> Instead of moving, all the such iodesc entries for UART controller > >> can > >> be removed for all Samsung SoC's now since the Samsung uart driver > >> does a ioremap during probe and any needed iomapping for earlyprintk > >> is handled by debug_ll_io_init(). > > > > Yes. This mapping should not be here, but... > > > > If you look at plat-samsung/pm.c, there is a debugging code that > > relies on presence of this mapping. > > Thanks for pointing this, I completely missed it. > > >So until this gets fixed/removed (I'm working on > > > > it right now), I'd suggest keeping Yadwinder's solution. > > But that debugging code is under "CONFIG_SAMSUNG_PM_DEBUG" > and SAMSUNG_PM_DEBUG selects DEBUG_LL also. > So the problem you stated below will their always when ever it will > enter that code Makes sense. > > The only problem is that the code in pm.c expects _all_ UARTs to be > > mapped (see s3c_pm_resture_uarts() and co.), so in case of DEBUG_LL > > enabled, something must be done ensure that rest of the ports are > > mapped. > how about fixing this problem with something like below: > saving only mapped/configured UART's registers. > > 8<---------------------------------------------------------------------- > ---------------------------------- diff --git > a/arch/arm/plat-samsung/pm.c b/arch/arm/plat-samsung/pm.c index > ea36136..34a7371 100644 > --- a/arch/arm/plat-samsung/pm.c > +++ b/arch/arm/plat-samsung/pm.c > @@ -102,10 +102,8 @@ static void s3c_pm_save_uart(unsigned int uart, > struct pm_u static void s3c_pm_save_uarts(void) > { > struct pm_uart_save *save = uart_save; > - unsigned int uart; > > - for (uart = 0; uart < CONFIG_SERIAL_SAMSUNG_UARTS; uart++, > save++) - s3c_pm_save_uart(uart, save); > + s3c_pm_save_uart(CONFIG_DEBUG_S3C_UART, save); > } > > static void s3c_pm_restore_uart(unsigned int uart, struct pm_uart_save > *save) > > 8<---------------------------------------------------------------------- > ------------------------------------ Looks good to me. Best regards, Tomasz -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/arm/plat-samsung/pm.c b/arch/arm/plat-samsung/pm.c index ea36136..34a7371 100644 --- a/arch/arm/plat-samsung/pm.c +++ b/arch/arm/plat-samsung/pm.c @@ -102,10 +102,8 @@ static void s3c_pm_save_uart(unsigned int uart, struct pm_u static void s3c_pm_save_uarts(void) { struct pm_uart_save *save = uart_save; - unsigned int uart; - for (uart = 0; uart < CONFIG_SERIAL_SAMSUNG_UARTS; uart++, save++) - s3c_pm_save_uart(uart, save); + s3c_pm_save_uart(CONFIG_DEBUG_S3C_UART, save); } static void s3c_pm_restore_uart(unsigned int uart, struct pm_uart_save *save)