Subject: Re: Patch to make ppc_md.progress useful on 4xx

From: David Gibson <[email-masked]>
Date: Thu, 21 Feb 2002 15:27:10 +1100

On Wed, Feb 20, 2002 at 08:26:00PM +0000, Armin wrote:
> David Gibson wrote:
> >Currently, ppc_md.progress on 4xx just does a printk(), which means
> >its messages won't be displayed until console_init() at which point
> >it's usually too late to be useful.
> >
> >The patch below changes ppc4xx_progress() to write directly to the
> >serial port.  I'd like to get comments before pushing the change,
> >because I don't want to break 4xx machines that I don't have (and so
> >can't test).
> >
> >At the moment it should only affect 405GP.  NP405H and NP405L support
> >should be trivial (I've only refrained from adding it because I can't
> >test it myself).  STBxxxx should be possible but will be much
> >yuckier.  It would be nice to have it work on all 4xx though, to get
> >rid of the nasty #ifdef in ppc4xx_setup.c.
>
> What Patch?
>
> I can test on some of the boards

Ah, crud.  Forgot to attach it.  Ok, this time for sure.

diff -urN /home/dgibson/kernel/linuxppc_2_4_devel/arch/ppc/kernel/head_4xx.S linux-grinch/arch/ppc/kernel/head_4xx.S
--- /home/dgibson/kernel/linuxppc_2_4_devel/arch/ppc/kernel/head_4xx.S	Sun Jan 27 08:21:22 2002
+++ linux-grinch/arch/ppc/kernel/head_4xx.S	Thu Feb 21 11:48:00 2002
@@ -1051,6 +1051,26 @@

 	tlbwe	r4,r0,TLB_DATA
 	tlbwe	r3,r0,TLB_TAG
+
+#if defined(CONFIG_SERIAL_TEXT_DEBUG) && defined(SERIAL_DEBUG_IO_BASE)
+
+	/* Load a TLB entry for the UART, so that ppc4xx_progress() can use
+	 * the UARTs nice and early.  We use a 4k real==virtual mapping. */
+
+	lis	r3,SERIAL_DEBUG_IO_BASE@h
+	ori	r3,r3,SERIAL_DEBUG_IO_BASE@l
+	mr	r4,r3
+	clrrwi	r4,r4,12
+	ori	r4,r4,(TLB_WR|TLB_I|TLB_M|TLB_G)
+
+	clrrwi	r3,r3,12
+	ori	r3,r3,(TLB_VALID | TLB_PAGESZ(PAGESZ_4K))
+
+	li	r0,0			/* TLB slot 0 */
+	tlbwe	r4,r0,TLB_DATA
+	tlbwe	r3,r0,TLB_TAG
+#endif /* CONFIG_SERIAL_DEBUG_TEXT && SERIAL_DEBUG_IO_BASE */
+
 	isync

 	/* Establish the exception vector base
diff -urN /home/dgibson/kernel/linuxppc_2_4_devel/arch/ppc/kernel/ppc4xx_setup.c linux-grinch/arch/ppc/kernel/ppc4xx_setup.c
--- /home/dgibson/kernel/linuxppc_2_4_devel/arch/ppc/kernel/ppc4xx_setup.c	Fri Feb  8 04:51:16 2002
+++ linux-grinch/arch/ppc/kernel/ppc4xx_setup.c	Thu Feb 21 11:45:40 2002
@@ -248,13 +248,36 @@
 	mtspr(SPRN_PIT, tb_ticks_per_jiffy);
 }

-#ifdef CONFIG_DEBUG_TEXT
+#ifdef CONFIG_SERIAL_TEXT_DEBUG
+
+/* We assume that the UART has already been initialized by the
+   firmware or the boot loader */
 static void
-ppc4xx_progress(char *s, unsigned short hex)
+serial_putc(u8 *com_port, unsigned char c)
 {
-	printk("%s\n\r", s);
+	while ((readb(com_port + (UART_LSR)) & UART_LSR_THRE) == 0)
+		;
+	writeb(c, com_port);
 }
+
+
+static void
+ppc4xx_progress(char *s, unsigned short hex)
+{
+	char c;
+#ifdef SERIAL_DEBUG_IO_BASE
+	u8 *com_port = (u8 *)SERIAL_DEBUG_IO_BASE;
+
+	while ((c = *s++) != '\0') {
+		serial_putc(com_port, c);
+	}
+	serial_putc(com_port, '\r');
+	serial_putc(com_port, '\n');
+#else
+	printk("%s\r\n");
 #endif
+}
+#endif /* CONFIG_SERIAL_TEXT_DEBUG */

 /*
  * IDE stuff.
@@ -381,7 +404,7 @@
 	ppc_md.find_end_of_memory = ppc4xx_find_end_of_memory;
 	ppc_md.setup_io_mappings = m4xx_map_io;

-#ifdef CONFIG_DEBUG_TEXT
+#ifdef CONFIG_SERIAL_TEXT_DEBUG
 	ppc_md.progress = ppc4xx_progress;
 #endif

diff -urN /home/dgibson/kernel/linuxppc_2_4_devel/arch/ppc/platforms/ibm405gp.h linux-grinch/arch/ppc/platforms/ibm405gp.h
--- /home/dgibson/kernel/linuxppc_2_4_devel/arch/ppc/platforms/ibm405gp.h	Fri Feb 15 11:27:58 2002
+++ linux-grinch/arch/ppc/platforms/ibm405gp.h	Thu Feb 21 11:44:58 2002
@@ -88,8 +88,8 @@
 #define UART1_INT	1

 #define PCIL0_BASE	0xEF400000
-#define UART0_IO_BASE	(u8 *) 0xEF600300
-#define UART1_IO_BASE	(u8 *) 0xEF600400
+#define UART0_IO_BASE	0xEF600300
+#define UART1_IO_BASE	0xEF600400
 #define IIC0_BASE	0xEF600500
 #define OPB0_BASE	0xEF600600
 #define GPIO0_BASE	0xEF600700
@@ -102,16 +102,18 @@
 #define STD_UART_OP(num)					\
 	{ 0, BASE_BAUD, 0, UART##num##_INT,			\
 		(ASYNC_BOOT_AUTOCONF | ASYNC_SKIP_TEST),	\
-		iomem_base: UART##num##_IO_BASE,		\
+		iomem_base: (u8 *)UART##num##_IO_BASE,		\
 		io_type: SERIAL_IO_MEM},

 #if defined(CONFIG_UART0_TTYS0)
+#define SERIAL_DEBUG_IO_BASE	UART0_IO_BASE
 #define SERIAL_PORT_DFNS	\
 	STD_UART_OP(0)		\
 	STD_UART_OP(1)
 #endif

 #if defined(CONFIG_UART0_TTYS1)
+#define SERIAL_DEBUG_IO_BASE	UART1_IO_BASE
 #define SERIAL_PORT_DFNS	\
 	STD_UART_OP(1)		\
 	STD_UART_OP(0)

--
David Gibson			| For every complex problem there is a
[email-masked]	| solution which is simple, neat and
				| wrong.  -- H.L. Mencken
http://www.ozlabs.org/people/dgibson

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