From mboxrd@z Thu Jan 1 00:00:00 1970 From: Siarhei Siamashka Date: Sun, 8 Feb 2015 05:43:41 +0200 Subject: [U-Boot] [PATCH v2 1/3] arm: Allow lr to be saved by board code In-Reply-To: <1423331250-8040-1-git-send-email-sjg@chromium.org> References: <1423331250-8040-1-git-send-email-sjg@chromium.org> Message-ID: <20150208054341.787e3b9d@i7> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Sat, 7 Feb 2015 10:47:28 -0700 Simon Glass wrote: > The link register value can be required on some boards (e.g. FEL mode on > sunxi) so use a branch instruction to jump to save_boot_params() instead > of a branch link. > > This requires a branch back to save_boot_params_ret so adjust the users > to deal with this. For exynos just drop the function since it doesn't > do anything. > > Signed-off-by: Simon Glass > --- > > Changes in v2: > - Change save_boot_params() to not use lr for return > - Fix up existing save_boot_params() functions for new API > > arch/arm/cpu/armv7/exynos/spl_boot.c | 1 - > arch/arm/cpu/armv7/omap-common/lowlevel_init.S | 2 +- > arch/arm/cpu/armv7/omap3/lowlevel_init.S | 2 +- > arch/arm/cpu/armv7/start.S | 7 +++++-- > arch/arm/include/asm/system.h | 15 +++++++++++++++ > board/nokia/rx51/lowlevel_init.S | 3 ++- > 6 files changed, 24 insertions(+), 6 deletions(-) > > diff --git a/arch/arm/cpu/armv7/exynos/spl_boot.c b/arch/arm/cpu/armv7/exynos/spl_boot.c > index bc237c9..c7f943e 100644 > --- a/arch/arm/cpu/armv7/exynos/spl_boot.c > +++ b/arch/arm/cpu/armv7/exynos/spl_boot.c > @@ -309,4 +309,3 @@ void board_init_r(gd_t *id, ulong dest_addr) > while (1) > ; > } > -void save_boot_params(u32 r0, u32 r1, u32 r2, u32 r3) {} > diff --git a/arch/arm/cpu/armv7/omap-common/lowlevel_init.S b/arch/arm/cpu/armv7/omap-common/lowlevel_init.S > index 86c0e42..e19c7ae 100644 > --- a/arch/arm/cpu/armv7/omap-common/lowlevel_init.S > +++ b/arch/arm/cpu/armv7/omap-common/lowlevel_init.S > @@ -19,7 +19,7 @@ > ENTRY(save_boot_params) > ldr r1, =OMAP_SRAM_SCRATCH_BOOT_PARAMS > str r0, [r1] > - bx lr > + b save_boot_params_ret > ENDPROC(save_boot_params) > > ENTRY(set_pl310_ctrl_reg) > diff --git a/arch/arm/cpu/armv7/omap3/lowlevel_init.S b/arch/arm/cpu/armv7/omap3/lowlevel_init.S > index 78577b1..80cb263 100644 > --- a/arch/arm/cpu/armv7/omap3/lowlevel_init.S > +++ b/arch/arm/cpu/armv7/omap3/lowlevel_init.S > @@ -23,7 +23,7 @@ ENTRY(save_boot_params) > ldr r5, [r0, #0x4] > and r5, r5, #0xff > str r5, [r4] > - bx lr > + b save_boot_params_ret > ENDPROC(save_boot_params) > #endif > > diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S > index 70048c1..9b49ece 100644 > --- a/arch/arm/cpu/armv7/start.S > +++ b/arch/arm/cpu/armv7/start.S > @@ -31,9 +31,12 @@ > *************************************************************************/ > > .globl reset > + .globl save_boot_params_ret > > reset: > - bl save_boot_params > + /* Allow the board to save important registers */ > + b save_boot_params > +save_boot_params_ret: > /* > * disable interrupts (FIQ and IRQ), also set the cpu to SVC32 mode, > * except if in HYP mode already > @@ -96,7 +99,7 @@ ENDPROC(c_runtime_cpu_setup) > * > *************************************************************************/ > ENTRY(save_boot_params) > - bx lr @ back to my caller > + b save_boot_params_ret @ back to my caller > ENDPROC(save_boot_params) > .weak save_boot_params > > diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h > index 89f2294..7820486 100644 > --- a/arch/arm/include/asm/system.h > +++ b/arch/arm/include/asm/system.h > @@ -142,6 +142,21 @@ void flush_l3_cache(void); > > #ifndef __ASSEMBLY__ > > +/** > + * save_boot_params() - Save boot parameters before starting reset sequence > + * > + * If you provide this function it will be called immediately U-Boot starts, > + * both for SPL and U-Boot proper. > + * > + * All registers are unchanged from U-Boot entry. No registers need be > + * preserved. > + * > + * This is not a normal C function. There is no stack. Return by branching to > + * save_boot_params_ret. > + * > + * void save_boot_params(u32 r0, u32 r1, u32 r2, u32 r3); > + */ > + > #define isb() __asm__ __volatile__ ("" : : : "memory") > > #define nop() __asm__ __volatile__("mov\tr0,r0\t@ nop\n\t"); > diff --git a/board/nokia/rx51/lowlevel_init.S b/board/nokia/rx51/lowlevel_init.S > index e252909..9d4ea1b 100644 > --- a/board/nokia/rx51/lowlevel_init.S > +++ b/board/nokia/rx51/lowlevel_init.S > @@ -37,7 +37,8 @@ ih_magic: /* IH_MAGIC in big endian from include/image.h */ > > .global save_boot_params > save_boot_params: > - > + /* Get return address */ > + ldr lr, =save_boot_params_ret > > /* Copy valid attached kernel to address KERNEL_ADDRESS */ > Acked-by: Siarhei Siamashka -- Best regards, Siarhei Siamashka