powerpc: Remove UDBG_RTAS_CONSOLE

The IBM Cell blade support was the last user of UDBG_RTAS_CONSOLE.

Although it's still possible to build it via
PPC_EARLY_DEBUG_UDBG_RTAS_CONSOLE, AFAIK it's not useful on any
other platfoms, because only Cell and JS20 era machines provided the
RTAS get/put-term-char functions.

If anyone is using it or needs it we can always resurrect it from git.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20241218105523.416573-19-mpe@ellerman.id.au

Author: mpe

arch/powerpc/Kconfig.debug

@@ -216,13 +216,6 @@ config PPC_EARLY_DEBUG_RTAS_PANEL
 	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_PAS_REALMODE
 	bool "PA Semi real mode"
 	depends on PPC_PASEMI

arch/powerpc/kernel/rtas.c

@@ -798,66 +798,6 @@ 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;
@@ -2135,21 +2075,6 @@ 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;
-
-	if (rtas_putchar_token != RTAS_UNKNOWN_SERVICE &&
-	    rtas_getchar_token != RTAS_UNKNOWN_SERVICE)
-		udbg_init_rtas_console();
-
-#endif
-
 	/* break now */
 	return 1;
 }

arch/powerpc/kernel/udbg.c

@@ -36,9 +36,6 @@ void __init udbg_early_init(void)
 #elif defined(CONFIG_PPC_EARLY_DEBUG_RTAS_PANEL)
 	/* RTAS panel debug */
 	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_PAS_REALMODE)
 	udbg_init_pas_realmode();
 #elif defined(CONFIG_PPC_EARLY_DEBUG_BOOTX)

arch/powerpc/platforms/Kconfig

@@ -70,10 +70,6 @@ config PPC_DT_CPU_FTRS
 	  firmware provides this binding.
 	  If you're not sure say Y.
 
-config UDBG_RTAS_CONSOLE
-	bool "RTAS based debug console"
-	depends on PPC_RTAS
-
 config PPC_SMP_MUXED_IPI
 	bool
 	help