ppc64: Add support for z85c30 SCCs for low level console (PowerMac G5)

This is only used with the "sccdbg" kernel command line option, as
you need a special adapter (www.geethree.com) to get access to the
serial port on those machines.

diff --git a/arch/ppc64/kernel/udbg.c b/arch/ppc64/kernel/udbg.c
index ab0f9564962988eae62ce1dd8bb070dcda4f1a9f..9f54b0a7c5c5c5d541cf1f6f96b67067eede2273 100644 (file)
--- a/arch/ppc64/kernel/udbg.c
+++ b/arch/ppc64/kernel/udbg.c
@@ -22,6 +22,9 @@
 #include <asm/naca.h>
 #include <asm/uaccess.h>
 #include <asm/machdep.h>
+#include <asm/io.h>
+#include <asm/prom.h>
+#include <asm/pmac_feature.h>
 
 struct NS16550 {
        /* this struct must be packed */
@@ -69,6 +72,61 @@ udbg_init_uart(void *comport)
        }
 }
 
+#ifdef CONFIG_PPC_PMAC
+
+#define        SCC_TXRDY       4
+#define SCC_RXRDY      1
+
+static volatile u8 *sccc, *sccd;
+
+static unsigned char scc_inittab[] = {
+    13, 0,             /* set baud rate divisor */
+    12, 0,
+    14, 1,             /* baud rate gen enable, src=rtxc */
+    11, 0x50,          /* clocks = br gen */
+    5,  0xea,          /* tx 8 bits, assert DTR & RTS */
+    4,  0x46,          /* x16 clock, 1 stop */
+    3,  0xc1,          /* rx enable, 8 bits */
+};
+
+void
+udbg_init_scc(struct device_node *np)
+{
+       unsigned long addr;
+       int i, x;
+
+       if (np == NULL)
+               np = of_find_node_by_name(NULL, "escc");
+       if (np == NULL)
+               return;
+       
+       /* Lock-enable the SCC channel */
+       pmac_call_feature(PMAC_FTR_SCC_ENABLE, np, PMAC_SCC_ASYNC | PMAC_SCC_FLAG_XMON, 1);
+
+       /* Setup for 57600 8N1 */
+       addr = np->addrs[0].address + 0x20;
+       sccc = (volatile u8 *) ioremap(addr & PAGE_MASK, PAGE_SIZE) ;
+       sccc += addr & ~PAGE_MASK;
+       sccd = sccc + 0x10;
+
+       for (i = 20000; i != 0; --i)
+               x = *sccc; eieio();
+       *sccc = 9; eieio();             /* reset A or B side */
+       *sccc = 0xc0; eieio();
+       for (i = 0; i < sizeof(scc_inittab); ++i) {
+               *sccc = scc_inittab[i];
+               eieio();
+       }
+
+       ppc_md.udbg_putc = udbg_putc;
+       ppc_md.udbg_getc = udbg_getc;
+       ppc_md.udbg_getc_poll = udbg_getc_poll;
+
+       udbg_puts("Hello World !\n");
+}
+
+#endif /* CONFIG_PPC_PMAC */
+
 void
 udbg_putc(unsigned char c)
 {
@@ -83,6 +141,16 @@ udbg_putc(unsigned char c)
                        udbg_comport->thr = '\r'; eieio();
                }
        }
+#ifdef CONFIG_PPC_PMAC
+       else if (sccc) {
+               while ((*sccc & SCC_TXRDY) == 0)
+                       eieio();
+               *sccd = c;              
+               eieio();
+               if (c == '\n')
+                       udbg_putc('\r');
+       }
+#endif /* CONFIG_PPC_PMAC */
 }
 
 int udbg_getc_poll(void)
@@ -93,6 +161,15 @@ int udbg_getc_poll(void)
                else
                        return -1;
        }
+#ifdef CONFIG_PPC_PMAC
+       else if (sccc) {
+               eieio();
+               if ((*sccc & SCC_RXRDY) != 0)
+                       return *sccd;
+               else
+                       return -1;
+       }
+#endif /* CONFIG_PPC_PMAC */
        return -1;
 }
 
@@ -104,6 +181,14 @@ udbg_getc(void)
                        /* wait for char */;
                return udbg_comport->rbr;
        }
+#ifdef CONFIG_PPC_PMAC
+       else if (sccc) {
+               eieio();
+               while ((*sccc & SCC_RXRDY) == 0)
+                       eieio();
+               return *sccd;
+       }
+#endif /* CONFIG_PPC_PMAC */
        return 0;
 }
 
@@ -149,6 +234,8 @@ udbg_read(char *buf, int buflen) {
                do {
                        c = ppc_md.udbg_getc();
                } while (c == 0x11 || c == 0x13);
+               if (c == 0)
+                       break;
                *p++ = c;
        }
        return i;