From d9b55a03611ff2e2e54fb4e1ad2648d5eb870fa3 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Tue, 8 May 2007 12:59:31 +1000 Subject: [PATCH] [POWERPC] Early serial debug support for PPC44x This adds support for early serial debugging via the built in port on IBM/AMCC PowerPC 44x CPUs. It uses a bolted TLB entry in address space 1 for the UART's mapping, allowing robust debugging both before and after the initialization of the MMU. Signed-off-by: David Gibson Signed-off-by: Paul Mackerras --- arch/powerpc/Kconfig.debug | 22 +++++++++++++---- arch/powerpc/kernel/head_44x.S | 34 ++++++++++----------------- arch/powerpc/kernel/of_platform.c | 1 - arch/powerpc/kernel/udbg.c | 3 +++ arch/powerpc/kernel/udbg_16550.c | 23 ++++++++++++++++++ arch/powerpc/platforms/44x/44x.h | 2 ++ arch/powerpc/platforms/44x/misc_44x.S | 31 ++++++++++++++++++++++++ include/asm-powerpc/mmu-44x.h | 6 +++++ include/asm-powerpc/udbg.h | 1 + 9 files changed, 97 insertions(+), 26 deletions(-) diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug index 86aa3745af7..f70e795c262 100644 --- a/arch/powerpc/Kconfig.debug +++ b/arch/powerpc/Kconfig.debug @@ -139,10 +139,6 @@ config BOOTX_TEXT Say Y here to see progress messages from the boot firmware in text mode. Requires either BootX or Open Firmware. -config SERIAL_TEXT_DEBUG - bool "Support for early boot texts over serial port" - depends on 4xx - config PPC_EARLY_DEBUG bool "Early debugging (dangerous)" @@ -207,6 +203,24 @@ config PPC_EARLY_DEBUG_BEAT help Select this to enable early debugging for Celleb with Beat. +config PPC_EARLY_DEBUG_44x + bool "Early serial debugging for IBM/AMCC 44x CPUs" + depends on 44x + select PPC_UDBG_16550 + help + Select this to enable early debugging for IBM 44x chips via the + inbuilt serial port. + endchoice +config PPC_EARLY_DEBUG_44x_PHYSLOW + hex "Low 32 bits of early debug UART physical address" + depends PPC_EARLY_DEBUG_44x + default "0x40000200" + +config PPC_EARLY_DEBUG_44x_PHYSHIGH + hex "EPRN of early debug UART physical address" + depends PPC_EARLY_DEBUG_44x + default "0x1" + endmenu diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S index a51026f0a9d..88695963f58 100644 --- a/arch/powerpc/kernel/head_44x.S +++ b/arch/powerpc/kernel/head_44x.S @@ -172,36 +172,28 @@ skpinv: addi r4,r4,1 /* Increment */ isync 4: -#ifdef CONFIG_SERIAL_TEXT_DEBUG - /* - * Add temporary UART mapping for early debug. - * We can map UART registers wherever we want as long as they don't - * interfere with other system mappings (e.g. with pinned entries). - * For an example of how we handle this - see ocotea.h. --ebs - */ +#ifdef CONFIG_PPC_EARLY_DEBUG_44x + /* Add UART mapping for early debug. */ + /* pageid fields */ - lis r3,UART0_IO_BASE@h - ori r3,r3,PPC44x_TLB_VALID | PPC44x_TLB_4K + lis r3,PPC44x_EARLY_DEBUG_VIRTADDR@h + ori r3,r3,PPC44x_TLB_VALID|PPC44x_TLB_TS|PPC44x_TLB_64K /* xlat fields */ - lis r4,UART0_PHYS_IO_BASE@h /* RPN depends on SoC */ -#ifndef CONFIG_440EP - ori r4,r4,0x0001 /* ERPN is 1 for second 4GB page */ -#endif + lis r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSLOW@h + ori r4,r4,CONFIG_PPC_EARLY_DEBUG_44x_PHYSHIGH /* attrib fields */ - li r5,0 - ori r5,r5,(PPC44x_TLB_SW | PPC44x_TLB_SR | PPC44x_TLB_I | PPC44x_TLB_G) + li r5,(PPC44x_TLB_SW|PPC44x_TLB_SR|PPC44x_TLB_I|PPC44x_TLB_G) + li r0,62 /* TLB slot 0 */ - li r0,0 /* TLB slot 0 */ - - tlbwe r3,r0,PPC44x_TLB_PAGEID /* Load the pageid fields */ - tlbwe r4,r0,PPC44x_TLB_XLAT /* Load the translation fields */ - tlbwe r5,r0,PPC44x_TLB_ATTRIB /* Load the attrib/access fields */ + tlbwe r3,r0,PPC44x_TLB_PAGEID + tlbwe r4,r0,PPC44x_TLB_XLAT + tlbwe r5,r0,PPC44x_TLB_ATTRIB /* Force context change */ isync -#endif /* CONFIG_SERIAL_TEXT_DEBUG */ +#endif /* CONFIG_PPC_EARLY_DEBUG_44x */ /* Establish the interrupt vector offsets */ SET_IVOR(0, CriticalInput); diff --git a/arch/powerpc/kernel/of_platform.c b/arch/powerpc/kernel/of_platform.c index 908ed7926db..84c34d979a8 100644 --- a/arch/powerpc/kernel/of_platform.c +++ b/arch/powerpc/kernel/of_platform.c @@ -29,7 +29,6 @@ #include #include - /* * The list of OF IDs below is used for matching bus types in the * system whose devices are to be exposed as of_platform_devices. diff --git a/arch/powerpc/kernel/udbg.c b/arch/powerpc/kernel/udbg.c index 7e0971868fc..7ef97ea8b3e 100644 --- a/arch/powerpc/kernel/udbg.c +++ b/arch/powerpc/kernel/udbg.c @@ -51,6 +51,9 @@ void __init udbg_early_init(void) udbg_init_pas_realmode(); #elif defined(CONFIG_BOOTX_TEXT) udbg_init_btext(); +#elif defined(CONFIG_PPC_EARLY_DEBUG_44x) + /* PPC44x debug */ + udbg_init_44x_as1(); #endif } diff --git a/arch/powerpc/kernel/udbg_16550.c b/arch/powerpc/kernel/udbg_16550.c index a963f657222..7afab5bcd61 100644 --- a/arch/powerpc/kernel/udbg_16550.c +++ b/arch/powerpc/kernel/udbg_16550.c @@ -191,3 +191,26 @@ void udbg_init_pas_realmode(void) udbg_getc_poll = NULL; } #endif /* CONFIG_PPC_MAPLE */ + +#ifdef CONFIG_PPC_EARLY_DEBUG_44x +#include + +static void udbg_44x_as1_putc(char c) +{ + if (udbg_comport) { + while ((as1_readb(&udbg_comport->lsr) & LSR_THRE) == 0) + /* wait for idle */; + as1_writeb(c, &udbg_comport->thr); eieio(); + if (c == '\n') + udbg_44x_as1_putc('\r'); + } +} + +void __init udbg_init_44x_as1(void) +{ + udbg_comport = + (volatile struct NS16550 __iomem *)PPC44x_EARLY_DEBUG_VIRTADDR; + + udbg_putc = udbg_44x_as1_putc; +} +#endif /* CONFIG_PPC_EARLY_DEBUG_44x */ diff --git a/arch/powerpc/platforms/44x/44x.h b/arch/powerpc/platforms/44x/44x.h index 45f24b166f4..42eabf87fea 100644 --- a/arch/powerpc/platforms/44x/44x.h +++ b/arch/powerpc/platforms/44x/44x.h @@ -1,6 +1,8 @@ #ifndef __POWERPC_PLATFORMS_44X_44X_H #define __POWERPC_PLATFORMS_44X_44X_H +extern u8 as1_readb(volatile u8 __iomem *addr); +extern void as1_writeb(u8 data, volatile u8 __iomem *addr); extern void ppc44x_reset_system(char *cmd); #endif /* __POWERPC_PLATFORMS_44X_44X_H */ diff --git a/arch/powerpc/platforms/44x/misc_44x.S b/arch/powerpc/platforms/44x/misc_44x.S index 52bde71485b..3bce71d5d75 100644 --- a/arch/powerpc/platforms/44x/misc_44x.S +++ b/arch/powerpc/platforms/44x/misc_44x.S @@ -14,6 +14,37 @@ .text +/* + * Do an IO access in AS1 + */ +_GLOBAL(as1_readb) + mfmsr r7 + ori r0,r7,MSR_DS + sync + mtmsr r0 + sync + isync + lbz r3,0(r3) + sync + mtmsr r7 + sync + isync + blr + +_GLOBAL(as1_writeb) + mfmsr r7 + ori r0,r7,MSR_DS + sync + mtmsr r0 + sync + isync + stb r3,0(r4) + sync + mtmsr r7 + sync + isync + blr + /* * void ppc44x_reset_system(char *cmd) * diff --git a/include/asm-powerpc/mmu-44x.h b/include/asm-powerpc/mmu-44x.h index 7bbc37e27d3..d5ce7a8dfe9 100644 --- a/include/asm-powerpc/mmu-44x.h +++ b/include/asm-powerpc/mmu-44x.h @@ -64,7 +64,13 @@ typedef struct { #endif /* !__ASSEMBLY__ */ +#ifndef CONFIG_PPC_EARLY_DEBUG_44x #define PPC44x_EARLY_TLBS 1 +#else +#define PPC44x_EARLY_TLBS 2 +#define PPC44x_EARLY_DEBUG_VIRTADDR (ASM_CONST(0xf0000000) \ + | (ASM_CONST(CONFIG_PPC_EARLY_DEBUG_44x_PHYSLOW) & 0xffff)) +#endif /* Size of the TLBs used for pinning in lowmem */ #define PPC_PIN_SIZE (1 << 28) /* 256M */ diff --git a/include/asm-powerpc/udbg.h b/include/asm-powerpc/udbg.h index d03d8557f70..ce9d82fb7b6 100644 --- a/include/asm-powerpc/udbg.h +++ b/include/asm-powerpc/udbg.h @@ -47,6 +47,7 @@ extern void __init udbg_init_rtas_panel(void); extern void __init udbg_init_rtas_console(void); extern void __init udbg_init_debug_beat(void); extern void __init udbg_init_btext(void); +extern void __init udbg_init_44x_as1(void); #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_UDBG_H */ -- 2.20.1