[POWERPC] Add udbg support for RTAS console

Add udbg hooks for the RTAS console, based on the RTAS put-term-char
and get-term-char calls. Along with my previous patches, this should
enable debugging as soon as early_init_dt_scan_rtas() is called.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c5e01c4..deea4c8 100644 (file)
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -420,6 +420,10 @@ config PPC_IBM_CELL_BLADE
        select MMIO_NVRAM
        select PPC_UDBG_16550
 
+config UDBG_RTAS_CONSOLE
+       bool
+       default n
+
 config XICS
        depends on PPC_PSERIES
        bool

diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
index c69006a..e29ef77 100644 (file)
--- a/arch/powerpc/Kconfig.debug
+++ b/arch/powerpc/Kconfig.debug
@@ -134,12 +134,19 @@ config PPC_EARLY_DEBUG_G5
        help
          Select this to enable early debugging for Apple G5 machines.
 
-config PPC_EARLY_DEBUG_RTAS
+config PPC_EARLY_DEBUG_RTAS_PANEL
        bool "RTAS Panel"
        depends on PPC_RTAS
        help
          Select this to enable early debugging via the RTAS panel.
 
+config PPC_EARLY_DEBUG_RTAS_CONSOLE
+       bool "RTAS Console"
+       depends on PPC_RTAS
+       select UDBG_RTAS_CONSOLE
+       help
+         Select this to enable early debugging via the RTAS console.
+
 config PPC_EARLY_DEBUG_MAPLE
        bool "Maple real mode"
        depends on PPC_MAPLE

diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 061d8af..4a4cb55 100644 (file)
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -109,11 +109,71 @@ static void call_rtas_display_status_delay(char c)
        }
 }
 
-void __init udbg_init_rtas(void)
+void __init udbg_init_rtas_panel(void)
 {
        udbg_putc = call_rtas_display_status_delay;
 }
 
+#ifdef CONFIG_UDBG_RTAS_CONSOLE
+
+/* If you think you're dying before early_init_dt_scan_rtas() does its
+ * work, you can hard code the token values for your firmware here and
+ * hardcode rtas.base/entry etc.
+ */
+static unsigned int rtas_putchar_token = RTAS_UNKNOWN_SERVICE;
+static unsigned int rtas_getchar_token = RTAS_UNKNOWN_SERVICE;
+
+static void udbg_rtascon_putc(char c)
+{
+       int tries;
+
+       if (!rtas.base)
+               return;
+
+       /* Add CRs before LFs */
+       if (c == '\n')
+               udbg_rtascon_putc('\r');
+
+       /* if there is more than one character to be displayed, wait a bit */
+       for (tries = 0; tries < 16; tries++) {
+               if (rtas_call(rtas_putchar_token, 1, 1, NULL, c) == 0)
+                       break;
+               udelay(1000);
+       }
+}
+
+static int udbg_rtascon_getc_poll(void)
+{
+       int c;
+
+       if (!rtas.base)
+               return -1;
+
+       if (rtas_call(rtas_getchar_token, 0, 2, &c))
+               return -1;
+
+       return c;
+}
+
+static int udbg_rtascon_getc(void)
+{
+       int c;
+
+       while ((c = udbg_rtascon_getc_poll()) == -1)
+               ;
+
+       return c;
+}
+
+
+void __init udbg_init_rtas_console(void)
+{
+       udbg_putc = udbg_rtascon_putc;
+       udbg_getc = udbg_rtascon_getc;
+       udbg_getc_poll = udbg_rtascon_getc_poll;
+}
+#endif /* CONFIG_UDBG_RTAS_CONSOLE */
+
 void rtas_progress(char *s, unsigned short hex)
 {
        struct device_node *root;
@@ -820,6 +880,16 @@ int __init early_init_dt_scan_rtas(unsigned long node,
                rtas.size = *sizep;
        }
 
+#ifdef CONFIG_UDBG_RTAS_CONSOLE
+       basep = of_get_flat_dt_prop(node, "put-term-char", NULL);
+       if (basep)
+               rtas_putchar_token = *basep;
+
+       basep = of_get_flat_dt_prop(node, "get-term-char", NULL);
+       if (basep)
+               rtas_getchar_token = *basep;
+#endif
+
        /* break now */
        return 1;
 }

diff --git a/arch/powerpc/kernel/udbg.c b/arch/powerpc/kernel/udbg.c
index 67d9fd9..759afd5 100644 (file)
--- a/arch/powerpc/kernel/udbg.c
+++ b/arch/powerpc/kernel/udbg.c
@@ -34,9 +34,12 @@ void __init udbg_early_init(void)
 #elif defined(CONFIG_PPC_EARLY_DEBUG_G5)
        /* For use on Apple G5 machines */
        udbg_init_pmac_realmode();
-#elif defined(CONFIG_PPC_EARLY_DEBUG_RTAS)
+#elif defined(CONFIG_PPC_EARLY_DEBUG_RTAS_PANEL)
        /* RTAS panel debug */
-       udbg_init_rtas();
+       udbg_init_rtas_panel();
+#elif defined(CONFIG_PPC_EARLY_DEBUG_RTAS_CONSOLE)
+       /* RTAS console debug */
+       udbg_init_rtas_console();
 #elif defined(CONFIG_PPC_EARLY_DEBUG_MAPLE)
        /* Maple real mode debug */
        udbg_init_maple_realmode();

diff --git a/include/asm-powerpc/udbg.h b/include/asm-powerpc/udbg.h
index 19a1517..55e5784 100644 (file)
--- a/include/asm-powerpc/udbg.h
+++ b/include/asm-powerpc/udbg.h
@@ -42,7 +42,8 @@ extern void __init udbg_init_debug_lpar(void);
 extern void __init udbg_init_pmac_realmode(void);
 extern void __init udbg_init_maple_realmode(void);
 extern void __init udbg_init_iseries(void);
-extern void __init udbg_init_rtas(void);
+extern void __init udbg_init_rtas_panel(void);
+extern void __init udbg_init_rtas_console(void);
 
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_UDBG_H */