m68k/mvme16x: Add support for EARLY_PRINTK

Added support for EARLY_PRINTK when running on an MVME16x board.
Signed-off-by: Kars de Jong <jongk@linux-m68k.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

arch/m68k/Kconfig.debug

@@ -2,6 +2,17 @@ menu "Kernel hacking"
 
 source "lib/Kconfig.debug"
 
+config EARLY_PRINTK
+	bool "Early printk" if EMBEDDED
+	depends on MVME16x
+	default y
+	help
+          Write kernel log output directly to a serial port.
+
+          This is useful for kernel debugging when your machine crashes very
+          early before the console code is initialized.
+          You should normally say N here, unless you want to debug such a crash.
+
 if !MMU
 
 config FULLDEBUG

arch/m68k/mvme16x/config.c

@@ -124,6 +124,163 @@ static void __init mvme16x_init_IRQ (void)
 #define PccSCCMICR	0x1d
 #define PccSCCTICR	0x1e
 #define PccSCCRICR	0x1f
+#define PccTPIACKR	0x25
+
+#ifdef CONFIG_EARLY_PRINTK
+
+/**** cd2401 registers ****/
+#define CD2401_ADDR	(0xfff45000)
+
+#define CyGFRCR         (0x81)
+#define CyCCR		(0x13)
+#define      CyCLR_CHAN		(0x40)
+#define      CyINIT_CHAN	(0x20)
+#define      CyCHIP_RESET	(0x10)
+#define      CyENB_XMTR		(0x08)
+#define      CyDIS_XMTR		(0x04)
+#define      CyENB_RCVR		(0x02)
+#define      CyDIS_RCVR		(0x01)
+#define CyCAR		(0xee)
+#define CyIER		(0x11)
+#define      CyMdmCh		(0x80)
+#define      CyRxExc		(0x20)
+#define      CyRxData		(0x08)
+#define      CyTxMpty		(0x02)
+#define      CyTxRdy		(0x01)
+#define CyLICR		(0x26)
+#define CyRISR		(0x89)
+#define      CyTIMEOUT		(0x80)
+#define      CySPECHAR		(0x70)
+#define      CyOVERRUN		(0x08)
+#define      CyPARITY		(0x04)
+#define      CyFRAME		(0x02)
+#define      CyBREAK		(0x01)
+#define CyREOIR		(0x84)
+#define CyTEOIR		(0x85)
+#define CyMEOIR		(0x86)
+#define      CyNOTRANS		(0x08)
+#define CyRFOC		(0x30)
+#define CyRDR		(0xf8)
+#define CyTDR		(0xf8)
+#define CyMISR		(0x8b)
+#define CyRISR		(0x89)
+#define CyTISR		(0x8a)
+#define CyMSVR1		(0xde)
+#define CyMSVR2		(0xdf)
+#define      CyDSR		(0x80)
+#define      CyDCD		(0x40)
+#define      CyCTS		(0x20)
+#define      CyDTR		(0x02)
+#define      CyRTS		(0x01)
+#define CyRTPRL		(0x25)
+#define CyRTPRH		(0x24)
+#define CyCOR1		(0x10)
+#define      CyPARITY_NONE	(0x00)
+#define      CyPARITY_E		(0x40)
+#define      CyPARITY_O		(0xC0)
+#define      Cy_5_BITS		(0x04)
+#define      Cy_6_BITS		(0x05)
+#define      Cy_7_BITS		(0x06)
+#define      Cy_8_BITS		(0x07)
+#define CyCOR2		(0x17)
+#define      CyETC		(0x20)
+#define      CyCtsAE		(0x02)
+#define CyCOR3		(0x16)
+#define      Cy_1_STOP		(0x02)
+#define      Cy_2_STOP		(0x04)
+#define CyCOR4		(0x15)
+#define      CyREC_FIFO		(0x0F)  /* Receive FIFO threshold */
+#define CyCOR5		(0x14)
+#define CyCOR6		(0x18)
+#define CyCOR7		(0x07)
+#define CyRBPR		(0xcb)
+#define CyRCOR		(0xc8)
+#define CyTBPR		(0xc3)
+#define CyTCOR		(0xc0)
+#define CySCHR1		(0x1f)
+#define CySCHR2 	(0x1e)
+#define CyTPR		(0xda)
+#define CyPILR1		(0xe3)
+#define CyPILR2		(0xe0)
+#define CyPILR3		(0xe1)
+#define CyCMR		(0x1b)
+#define      CyASYNC		(0x02)
+#define CyLICR          (0x26)
+#define CyLIVR          (0x09)
+#define CySCRL		(0x23)
+#define CySCRH		(0x22)
+#define CyTFTC		(0x80)
+
+static void cons_write(struct console *co, const char *str, unsigned count)
+{
+	volatile unsigned char *base_addr = (u_char *)CD2401_ADDR;
+	volatile u_char sink;
+	u_char ier;
+	int port;
+	u_char do_lf = 0;
+	int i = 0;
+
+	/* Ensure transmitter is enabled! */
+
+	port = 0;
+	base_addr[CyCAR] = (u_char)port;
+	while (base_addr[CyCCR])
+		;
+	base_addr[CyCCR] = CyENB_XMTR;
+
+	ier = base_addr[CyIER];
+	base_addr[CyIER] = CyTxMpty;
+
+	while (1) {
+		if (pcc2chip[PccSCCTICR] & 0x20)
+		{
+			/* We have a Tx int. Acknowledge it */
+			sink = pcc2chip[PccTPIACKR];
+			if ((base_addr[CyLICR] >> 2) == port) {
+				if (i == count) {
+					/* Last char of string is now output */
+					base_addr[CyTEOIR] = CyNOTRANS;
+					break;
+				}
+				if (do_lf) {
+					base_addr[CyTDR] = '\n';
+					str++;
+					i++;
+					do_lf = 0;
+				}
+				else if (*str == '\n') {
+					base_addr[CyTDR] = '\r';
+					do_lf = 1;
+				}
+				else {
+					base_addr[CyTDR] = *str++;
+					i++;
+				}
+				base_addr[CyTEOIR] = 0;
+			}
+			else
+				base_addr[CyTEOIR] = CyNOTRANS;
+		}
+	}
+
+	base_addr[CyIER] = ier;
+}
+
+static struct console cons_info =
+{
+	.name	= "sercon",
+	.write	= cons_write,
+	.flags	= CON_PRINTBUFFER | CON_BOOT,
+	.index	= -1,
+};
+
+static void __init mvme16x_early_console(void)
+{
+	register_console(&cons_info);
+
+	printk(KERN_INFO "MVME16x: early console registered\n");
+}
+#endif
 
 void __init config_mvme16x(void)
 {
@@ -183,6 +340,9 @@ void __init config_mvme16x(void)
 	pcc2chip[PccSCCMICR] = 0x10;
 	pcc2chip[PccSCCTICR] = 0x10;
 	pcc2chip[PccSCCRICR] = 0x10;
+#ifdef CONFIG_EARLY_PRINTK
+	mvme16x_early_console();
+#endif
     }
 }