[MIPS] Add CFE support to BCM47XX

Add CFE support to the BCM47XX code.  That includes querying CFE environment
variables as well as using CFE to print messages before the serial port is
initialized (early printk).
    
Signed-off-by: Aurelien Jarno <aurel32@farad.aurel32.net>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 111 insertions, 2 deletions

diff --git a/arch/mips/bcm47xx/prom.c b/arch/mips/bcm47xx/prom.c
index 41ac9dd88bde..079e33d52783 100644
--- a/arch/mips/bcm47xx/prom.c
+++ b/arch/mips/bcm47xx/prom.c
@@ -1,5 +1,6 @@
 /*
  *  Copyright (C) 2004 Florian Schirmer <jolt@tuxbox.org>
+ *  Copyright (C) 2007 Aurelien Jarno <aurelien@aurel32.net>
  *
  *  This program is free software; you can redistribute  it and/or modify it
  *  under  the terms of  the GNU General  Public License as published by the
@@ -23,18 +24,117 @@
  */
 
 #include <linux/init.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/spinlock.h>
 #include <asm/bootinfo.h>
+#include <asm/fw/cfe/cfe_api.h>
+#include <asm/fw/cfe/cfe_error.h>
+
+static int cfe_cons_handle;
 
 const char *get_system_type(void)
 {
 	return "Broadcom BCM47XX";
 }
 
-void __init prom_init(void)
+void prom_putchar(char c)
+{
+	while (cfe_write(cfe_cons_handle, &c, 1) == 0)
+		;
+}
+
+static __init void prom_init_cfe(void)
+{
+	uint32_t cfe_ept;
+	uint32_t cfe_handle;
+	uint32_t cfe_eptseal;
+	int argc = fw_arg0;
+	char **envp = (char **) fw_arg2;
+	int *prom_vec = (int *) fw_arg3;
+
+	/*
+	 * Check if a loader was used; if NOT, the 4 arguments are
+	 * what CFE gives us (handle, 0, EPT and EPTSEAL)
+	 */
+	if (argc < 0) {
+		cfe_handle = (uint32_t)argc;
+		cfe_ept = (uint32_t)envp;
+		cfe_eptseal = (uint32_t)prom_vec;
+	} else {
+		if ((int)prom_vec < 0) {
+			/*
+			 * Old loader; all it gives us is the handle,
+			 * so use the "known" entrypoint and assume
+			 * the seal.
+			 */
+			cfe_handle = (uint32_t)prom_vec;
+			cfe_ept = 0xBFC00500;
+			cfe_eptseal = CFE_EPTSEAL;
+		} else {
+			/*
+			 * Newer loaders bundle the handle/ept/eptseal
+			 * Note: prom_vec is in the loader's useg
+			 * which is still alive in the TLB.
+			 */
+			cfe_handle = prom_vec[0];
+			cfe_ept = prom_vec[2];
+			cfe_eptseal = prom_vec[3];
+		}
+	}
+
+	if (cfe_eptseal != CFE_EPTSEAL) {
+		/* too early for panic to do any good */
+		printk(KERN_ERR "CFE's entrypoint seal doesn't match.");
+		while (1) ;
+	}
+
+	cfe_init(cfe_handle, cfe_ept);
+}
+
+static __init void prom_init_console(void)
+{
+	/* Initialize CFE console */
+	cfe_cons_handle = cfe_getstdhandle(CFE_STDHANDLE_CONSOLE);
+}
+
+static __init void prom_init_cmdline(void)
+{
+	char buf[CL_SIZE];
+
+	/* Get the kernel command line from CFE */
+	if (cfe_getenv("LINUX_CMDLINE", buf, CL_SIZE) >= 0) {
+		buf[CL_SIZE-1] = 0;
+		strcpy(arcs_cmdline, buf);
+	}
+
+	/* Force a console handover by adding a console= argument if needed,
+	 * as CFE is not available anymore later in the boot process. */
+	if ((strstr(arcs_cmdline, "console=")) == NULL) {
+		/* Try to read the default serial port used by CFE */
+		if ((cfe_getenv("BOOT_CONSOLE", buf, CL_SIZE) < 0)
+		    || (strncmp("uart", buf, 4)))
+			/* Default to uart0 */
+			strcpy(buf, "uart0");
+
+		/* Compute the new command line */
+		snprintf(arcs_cmdline, CL_SIZE, "%s console=ttyS%c,115200",
+			 arcs_cmdline, buf[4]);
+	}
+}
+
+static __init void prom_init_mem(void)
 {
 	unsigned long mem;
 
-	/* Figure out memory size by finding aliases */
+	/* Figure out memory size by finding aliases.
+	 *
+	 * We should theoretically use the mapping from CFE using cfe_enummem().
+	 * However as the BCM47XX is mostly used on low-memory systems, we
+	 * want to reuse the memory used by CFE (around 4MB). That means cfe_*
+	 * functions stop to work at some point during the boot, we should only
+	 * call them at the beginning of the boot.
+	 */
 	for (mem = (1 << 20); mem < (128 << 20); mem += (1 << 20)) {
 		if (*(unsigned long *)((unsigned long)(prom_init) + mem) ==
 		    *(unsigned long *)(prom_init))
@@ -44,6 +144,15 @@ void __init prom_init(void)
 	add_memory_region(0, mem, BOOT_MEM_RAM);
 }
 
+void __init prom_init(void)
+{
+	prom_init_cfe();
+	prom_init_console();
+	prom_init_cmdline();
+	prom_init_mem();
+}
+
 void __init prom_free_prom_memory(void)
 {
 }
+