[POWERPC] 4xx: Add early udbg support for 40x processors
This adds some basic real mode based early udbg support for 40x
in order to debug things more easily
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
index ea11378..be09f0d 100644
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -206,6 +206,45 @@
isync
blr /* Done */
+#ifdef CONFIG_40x
+
+/*
+ * Do an IO access in real mode
+ */
+_GLOBAL(real_readb)
+ mfmsr r7
+ ori r0,r7,MSR_DR
+ xori r0,r0,MSR_DR
+ sync
+ mtmsr r0
+ sync
+ isync
+ lbz r3,0(r3)
+ sync
+ mtmsr r7
+ sync
+ isync
+ blr
+
+ /*
+ * Do an IO access in real mode
+ */
+_GLOBAL(real_writeb)
+ mfmsr r7
+ ori r0,r7,MSR_DR
+ xori r0,r0,MSR_DR
+ sync
+ mtmsr r0
+ sync
+ isync
+ stb r3,0(r4)
+ sync
+ mtmsr r7
+ sync
+ isync
+ blr
+
+#endif /* CONFIG_40x */
/*
* Flush MMU TLB
diff --git a/arch/powerpc/kernel/udbg.c b/arch/powerpc/kernel/udbg.c
index eba148f..7aad620 100644
--- a/arch/powerpc/kernel/udbg.c
+++ b/arch/powerpc/kernel/udbg.c
@@ -54,6 +54,9 @@
#elif defined(CONFIG_PPC_EARLY_DEBUG_44x)
/* PPC44x debug */
udbg_init_44x_as1();
+#elif defined(CONFIG_PPC_EARLY_DEBUG_40x)
+ /* PPC40x debug */
+ udbg_init_40x_realmode();
#elif defined(CONFIG_PPC_EARLY_DEBUG_CPM)
udbg_init_cpm();
#endif
diff --git a/arch/powerpc/kernel/udbg_16550.c b/arch/powerpc/kernel/udbg_16550.c
index df740ea..cb01ebc 100644
--- a/arch/powerpc/kernel/udbg_16550.c
+++ b/arch/powerpc/kernel/udbg_16550.c
@@ -225,3 +225,36 @@
udbg_getc = udbg_44x_as1_getc;
}
#endif /* CONFIG_PPC_EARLY_DEBUG_44x */
+
+#ifdef CONFIG_PPC_EARLY_DEBUG_40x
+static void udbg_40x_real_putc(char c)
+{
+ if (udbg_comport) {
+ while ((real_readb(&udbg_comport->lsr) & LSR_THRE) == 0)
+ /* wait for idle */;
+ real_writeb(c, &udbg_comport->thr); eieio();
+ if (c == '\n')
+ udbg_40x_real_putc('\r');
+ }
+}
+
+static int udbg_40x_real_getc(void)
+{
+ if (udbg_comport) {
+ while ((real_readb(&udbg_comport->lsr) & LSR_DR) == 0)
+ ; /* wait for char */
+ return real_readb(&udbg_comport->rbr);
+ }
+ return -1;
+}
+
+void __init udbg_init_40x_realmode(void)
+{
+ udbg_comport = (struct NS16550 __iomem *)
+ CONFIG_PPC_EARLY_DEBUG_40x_PHYSADDR;
+
+ udbg_putc = udbg_40x_real_putc;
+ udbg_getc = udbg_40x_real_getc;
+ udbg_getc_poll = NULL;
+}
+#endif /* CONFIG_PPC_EARLY_DEBUG_40x */