Blackfin arch: kgdb specific code

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

Documentation/blackfin/kgdb.txt

+			A Simple Guide to Configure KGDB
+
+			Sonic Zhang <sonic.zhang@analog.com>
+				Aug. 24th 2006
+
+
+This KGDB patch enables the kernel developer to do source level debugging on
+the kernel for the Blackfin architecture.  The debugging works over either the
+ethernet interface or one of the uarts.  Both software breakpoints and
+hardware breakpoints are supported in this version.
+http://docs.blackfin.uclinux.org/doku.php?id=kgdb
+
+
+2 known issues:
+1. This bug:
+       http://blackfin.uclinux.org/tracker/index.php?func=detail&aid=544&group_id=18&atid=145
+   The GDB client for Blackfin uClinux causes incorrect values of local
+   variables to be displayed when the user breaks the running of kernel in GDB.
+2. Because of a hardware bug in Blackfin 533 v1.0.3:
+       05000067 - Watchpoints (Hardware Breakpoints) are not supported
+   Hardware breakpoints cannot be set properly.
+
+
+Debug over Ethernet:
+ 
+1. Compile and install the cross platform version of gdb for blackfin, which
+   can be found at $(BINROOT)/bfin-elf-gdb.
+
+2. Apply this patch to the 2.6.x kernel.  Select the menuconfig option under
+   "Kernel hacking" -> "Kernel debugging" -> "KGDB: kernel debug with remote gdb".
+   With this selected, option "Full Symbolic/Source Debugging support" and 
+   "Compile the kernel with frame pointers" are also selected.
+
+3. Select option "KGDB: connect over (Ethernet)".  Add "kgdboe=@target-IP/,@host-IP/" to
+   the option "Compiled-in Kernel Boot Parameter" under "Kernel hacking".
+
+4. Connect minicom to the serial port and boot the kernel image.
+
+5. Configure the IP "/> ifconfig eth0 target-IP"
+
+6. Start GDB client "bfin-elf-gdb vmlinux".
+
+7. Connect to the target "(gdb) target remote udp:target-IP:6443".
+
+8. Set software breakpoint "(gdb) break sys_open".
+
+9. Continue "(gdb) c".
+
+10. Run ls in the target console "/> ls".
+
+11. Breakpoint hits. "Breakpoint 1: sys_open(..."
+
+12. Display local variables and function paramters.
+    (*) This operation gives wrong results, see known issue 1.
+
+13. Single stepping "(gdb) si".
+
+14. Remove breakpoint 1. "(gdb) del 1"
+
+15. Set hardware breakpoint "(gdb) hbreak sys_open".
+
+16. Continue "(gdb) c".
+
+17. Run ls in the target console "/> ls".
+
+18. Hardware breakpoint hits. "Breakpoint 1: sys_open(...".
+    (*) This hardware breakpoint will not be hit, see known issue 2.
+
+19. Continue "(gdb) c".
+
+20. Interrupt the target in GDB "Ctrl+C".
+
+21. Detach from the target "(gdb) detach".
+
+22. Exit GDB "(gdb) quit".
+
+
+Debug over the UART:
+
+1. Compile and install the cross platform version of gdb for blackfin, which
+   can be found at $(BINROOT)/bfin-elf-gdb.
+
+2. Apply this patch to the 2.6.x kernel.  Select the menuconfig option under
+   "Kernel hacking" -> "Kernel debugging" -> "KGDB: kernel debug with remote gdb".
+   With this selected, option "Full Symbolic/Source Debugging support" and 
+   "Compile the kernel with frame pointers" are also selected.
+
+3. Select option "KGDB: connect over (UART)".  Set "KGDB: UART port number" to be
+   a different one from the console.  Don't forget to change the mode of
+   blackfin serial driver to PIO.  Otherwise kgdb works incorrectly on UART.
+ 
+4. If you want connect to kgdb when the kernel boots, enable
+   "KGDB: Wait for gdb connection early" 
+
+5. Compile kernel.
+
+6. Connect minicom to the serial port of the console and boot the kernel image.
+
+7. Start GDB client "bfin-elf-gdb vmlinux".
+
+8. Set the baud rate in GDB "(gdb) set remotebaud 57600".
+
+9. Connect to the target on the second serial port "(gdb) target remote /dev/ttyS1".
+
+10. Set software breakpoint "(gdb) break sys_open".
+
+11. Continue "(gdb) c". 
+
+12. Run ls in the target console "/> ls". 
+
+13. A breakpoint is hit. "Breakpoint 1: sys_open(..."
+
+14. All other operations are the same as that in KGDB over Ethernet. 
+
+
+Debug over the same UART as console:
+
+1. Compile and install the cross platform version of gdb for blackfin, which
+   can be found at $(BINROOT)/bfin-elf-gdb.
+
+2. Apply this patch to the 2.6.x kernel.  Select the menuconfig option under
+   "Kernel hacking" -> "Kernel debugging" -> "KGDB: kernel debug with remote gdb".
+   With this selected, option "Full Symbolic/Source Debugging support" and 
+   "Compile the kernel with frame pointers" are also selected.
+
+3. Select option "KGDB: connect over UART".  Set "KGDB: UART port number" to console.
+   Don't forget to change the mode of blackfin serial driver to PIO.
+   Otherwise kgdb works incorrectly on UART.
+ 
+4. If you want connect to kgdb when the kernel boots, enable
+   "KGDB: Wait for gdb connection early" 
+
+5. Connect minicom to the serial port and boot the kernel image. 
+
+6. (Optional) Ask target to wait for gdb connection by entering Ctrl+A. In minicom, you should enter Ctrl+A+A.
+
+7. Start GDB client "bfin-elf-gdb vmlinux".
+
+8. Set the baud rate in GDB "(gdb) set remotebaud 57600".
+
+9. Connect to the target "(gdb) target remote /dev/ttyS0".
+
+10. Set software breakpoint "(gdb) break sys_open".
+
+11. Continue "(gdb) c". Then enter Ctrl+C twice to stop GDB connection.
+
+12. Run ls in the target console "/> ls". Dummy string can be seen on the console.
+
+13. Then connect the gdb to target again. "(gdb) target remote /dev/ttyS0".
+    Now you will find a breakpoint is hit. "Breakpoint 1: sys_open(..."
+
+14. All other operations are the same as that in KGDB over Ethernet.  The only
+    difference is that after continue command in GDB, please stop GDB
+    connection by 2 "Ctrl+C"s and connect again after breakpoints are hit or
+    Ctrl+A is entered.

arch/blackfin/kernel/Makefile

@@ -14,3 +14,4 @@ obj-$(CONFIG_BF561)		     += bfin_gpio.o
 obj-$(CONFIG_MODULES)                += module.o
 obj-$(CONFIG_BFIN_DMA_5XX)           += bfin_dma_5xx.o
 obj-$(CONFIG_DUAL_CORE_TEST_MODULE)  += dualcore_test.o
+obj-$(CONFIG_KGDB)                   += kgdb.o

drivers/serial/Kconfig

@@ -556,7 +556,7 @@ choice
 
 config SERIAL_BFIN_DMA
 	bool "DMA mode"
-	depends on DMA_UNCACHED_1M
+	depends on DMA_UNCACHED_1M && !KGDB_UART
 	help
 	  This driver works under DMA mode. If this option is selected, the
 	  blackfin simple dma driver is also enabled.

drivers/serial/bfin_5xx.c

@@ -41,6 +41,11 @@
 #include <linux/tty_flip.h>
 #include <linux/serial_core.h>
 
+#ifdef CONFIG_KGDB_UART
+#include <linux/kgdb.h>
+#include <asm/irq_regs.h>
+#endif
+
 #include <asm/gpio.h>
 #include <asm/mach/bfin_serial_5xx.h>
 
@@ -119,6 +124,9 @@ static void bfin_serial_stop_rx(struct uart_port *port)
 	unsigned short ier;
 
 	ier = UART_GET_IER(uart);
+#ifdef	CONFIG_KGDB_UART
+	if (uart->port.line != CONFIG_KGDB_UART_PORT)
+#endif
 	ier &= ~ERBFI;
 	UART_PUT_IER(uart, ier);
 }
@@ -130,6 +138,49 @@ static void bfin_serial_enable_ms(struct uart_port *port)
 {
 }
 
+#ifdef CONFIG_KGDB_UART
+static int kgdb_entry_state;
+
+void kgdb_put_debug_char(int chr)
+{
+	struct bfin_serial_port *uart;
+	
+	if (CONFIG_KGDB_UART_PORT<0 || CONFIG_KGDB_UART_PORT>=NR_PORTS)
+		uart = &bfin_serial_ports[0];
+	else
+		uart = &bfin_serial_ports[CONFIG_KGDB_UART_PORT];
+	
+	while (!(UART_GET_LSR(uart) & THRE)) {
+		__builtin_bfin_ssync();
+	}
+	UART_PUT_LCR(uart, UART_GET_LCR(uart)&(~DLAB));
+	__builtin_bfin_ssync();
+	UART_PUT_CHAR(uart, (unsigned char)chr);
+	__builtin_bfin_ssync();
+}
+
+int kgdb_get_debug_char(void)
+{
+	struct bfin_serial_port *uart;
+	unsigned char chr;
+
+	if (CONFIG_KGDB_UART_PORT<0 || CONFIG_KGDB_UART_PORT>=NR_PORTS)
+		uart = &bfin_serial_ports[0];
+	else
+		uart = &bfin_serial_ports[CONFIG_KGDB_UART_PORT];
+	
+	while(!(UART_GET_LSR(uart) & DR)) {
+		__builtin_bfin_ssync();
+	}
+	UART_PUT_LCR(uart, UART_GET_LCR(uart)&(~DLAB));
+	__builtin_bfin_ssync();
+	chr = UART_GET_CHAR(uart);
+	__builtin_bfin_ssync();
+
+	return chr;
+}
+#endif
+
 #ifdef CONFIG_SERIAL_BFIN_PIO
 static void local_put_char(struct bfin_serial_port *uart, char ch)
 {
@@ -152,6 +203,9 @@ static void bfin_serial_rx_chars(struct bfin_serial_port *uart)
 {
 	struct tty_struct *tty = uart->port.info->tty;
 	unsigned int status, ch, flg;
+#ifdef CONFIG_KGDB_UART
+	struct pt_regs *regs = get_irq_regs();
+#endif
 #ifdef BF533_FAMILY
 	static int in_break = 0;
 #endif
@@ -160,6 +214,27 @@ static void bfin_serial_rx_chars(struct bfin_serial_port *uart)
  	ch = UART_GET_CHAR(uart);
  	uart->port.icount.rx++;
 
+#ifdef CONFIG_KGDB_UART
+	if (uart->port.line == CONFIG_KGDB_UART_PORT) {
+		if (uart->port.cons->index == CONFIG_KGDB_UART_PORT && ch == 0x1) { /* Ctrl + A */
+			kgdb_breakkey_pressed(regs);
+			return;
+		} else if (kgdb_entry_state == 0 && ch == '$') {/* connection from KGDB */
+			kgdb_entry_state = 1;
+		} else if (kgdb_entry_state == 1 && ch == 'q') {
+			kgdb_entry_state = 0;
+			kgdb_breakkey_pressed(regs);
+			return;
+		} else if (ch == 0x3) {/* Ctrl + C */
+			kgdb_entry_state = 0;
+			kgdb_breakkey_pressed(regs);
+			return;
+		} else {
+			kgdb_entry_state = 0;
+		}
+	}
+#endif
+ 
 #ifdef BF533_FAMILY
 	/* The BF533 family of processors have a nice misbehavior where
 	 * they continuously generate characters for a "single" break.
@@ -571,7 +646,11 @@ static int bfin_serial_startup(struct uart_port *port)
 	uart->rx_dma_timer.expires = jiffies + DMA_RX_FLUSH_JIFFIES;
 	add_timer(&(uart->rx_dma_timer));
 #else
+# ifdef	CONFIG_KGDB_UART
+	if (uart->port.line != CONFIG_KGDB_UART_PORT && request_irq
+# else
 	if (request_irq
+# endif
 	    (uart->port.irq, bfin_serial_rx_int, IRQF_DISABLED,
 	     "BFIN_UART_RX", uart)) {
 		printk(KERN_NOTICE "Unable to attach BlackFin UART RX interrupt\n");
@@ -601,6 +680,9 @@ static void bfin_serial_shutdown(struct uart_port *port)
 	free_dma(uart->rx_dma_channel);
 	del_timer(&(uart->rx_dma_timer));
 #else
+#ifdef	CONFIG_KGDB_UART
+	if (uart->port.line != CONFIG_KGDB_UART_PORT)
+#endif
 	free_irq(uart->port.irq, uart);
 	free_irq(uart->port.irq+1, uart);
 #endif
@@ -931,6 +1013,10 @@ static int __init bfin_serial_rs_console_init(void)
 {
 	bfin_serial_init_ports();
 	register_console(&bfin_serial_console);
+#ifdef CONFIG_KGDB_UART
+	kgdb_entry_state = 0;
+	init_kgdb_uart();
+#endif
 	return 0;
 }
 console_initcall(bfin_serial_rs_console_init);
@@ -1023,6 +1109,10 @@ static struct platform_driver bfin_serial_driver = {
 static int __init bfin_serial_init(void)
 {
 	int ret;
+#ifdef CONFIG_KGDB_UART
+	struct bfin_serial_port *uart = &bfin_serial_ports[CONFIG_KGDB_UART_PORT];
+	struct termios t;
+#endif
 
 	pr_info("Serial: Blackfin serial driver\n");
 
@@ -1036,6 +1126,21 @@ static int __init bfin_serial_init(void)
 			uart_unregister_driver(&bfin_serial_reg);
 		}
 	}
+#ifdef CONFIG_KGDB_UART
+	if (uart->port.cons->index != CONFIG_KGDB_UART_PORT) {
+		request_irq(uart->port.irq, bfin_serial_int,
+			IRQF_DISABLED, "BFIN_UART_RX", uart);
+		pr_info("Request irq for kgdb uart port\n");
+		UART_PUT_IER(uart, UART_GET_IER(uart) | ERBFI);
+		__builtin_bfin_ssync();
+		t.c_cflag = CS8|B57600;
+		t.c_iflag = 0;
+		t.c_oflag = 0;
+		t.c_lflag = ICANON;
+		t.c_line = CONFIG_KGDB_UART_PORT;
+		bfin_serial_set_termios(&uart->port, &t, &t);
+	}
+#endif
 	return ret;
 }
 

include/asm-blackfin/kgdb.h

+/*
+ * File:         include/asm-blackfin/kgdb.h
+ * Based on:
+ * Author:       Sonic Zhang
+ *
+ * Created:
+ * Description:
+ *
+ * Rev:          $Id: kgdb_bfin_linux-2.6.x.patch 4934 2007-02-13 09:32:11Z sonicz $
+ *
+ * Modified:
+ *               Copyright 2005-2006 Analog Devices Inc.
+ *
+ * Bugs:         Enter bugs at http://blackfin.uclinux.org/
+ *
+ * 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 Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see the file COPYING, or write
+ * to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#ifndef __ASM_BLACKFIN_KGDB_H__
+#define __ASM_BLACKFIN_KGDB_H__
+
+#include <linux/ptrace.h>
+
+/* gdb locks */
+#define KGDB_MAX_NO_CPUS 8
+
+/************************************************************************/
+/* BUFMAX defines the maximum number of characters in inbound/outbound buffers*/
+/* at least NUMREGBYTES*2 are needed for register packets */
+/* Longer buffer is needed to list all threads */
+#define BUFMAX 2048
+
+/*
+ *  Note that this register image is different from
+ *  the register image that Linux produces at interrupt time.
+ *  
+ *  Linux's register image is defined by struct pt_regs in ptrace.h.
+ */
+enum regnames {
+  /* Core Registers */
+  BFIN_R0 = 0,
+  BFIN_R1,
+  BFIN_R2,
+  BFIN_R3,
+  BFIN_R4,
+  BFIN_R5,
+  BFIN_R6,
+  BFIN_R7,
+  BFIN_P0,
+  BFIN_P1,
+  BFIN_P2,
+  BFIN_P3,
+  BFIN_P4,
+  BFIN_P5,
+  BFIN_SP,
+  BFIN_FP,
+  BFIN_I0,
+  BFIN_I1,
+  BFIN_I2,
+  BFIN_I3,
+  BFIN_M0,
+  BFIN_M1,
+  BFIN_M2,
+  BFIN_M3,
+  BFIN_B0,
+  BFIN_B1,
+  BFIN_B2,
+  BFIN_B3,
+  BFIN_L0,
+  BFIN_L1,
+  BFIN_L2,
+  BFIN_L3,
+  BFIN_A0_DOT_X,
+  BFIN_A0_DOT_W,
+  BFIN_A1_DOT_X,
+  BFIN_A1_DOT_W,
+  BFIN_ASTAT,
+  BFIN_RETS,
+  BFIN_LC0,
+  BFIN_LT0,
+  BFIN_LB0,
+  BFIN_LC1,
+  BFIN_LT1,
+  BFIN_LB1,
+  BFIN_CYCLES,
+  BFIN_CYCLES2,
+  BFIN_USP,
+  BFIN_SEQSTAT,
+  BFIN_SYSCFG,
+  BFIN_RETI,
+  BFIN_RETX,
+  BFIN_RETN,
+  BFIN_RETE,
+  
+  /* Pseudo Registers */
+  BFIN_PC,
+  BFIN_CC,
+  BFIN_EXTRA1,		/* Address of .text section.  */
+  BFIN_EXTRA2,		/* Address of .data section.  */
+  BFIN_EXTRA3,		/* Address of .bss section.  */
+  BFIN_FDPIC_EXEC, 
+  BFIN_FDPIC_INTERP,
+
+  /* MMRs */
+  BFIN_IPEND,
+
+  /* LAST ENTRY SHOULD NOT BE CHANGED.  */
+  BFIN_NUM_REGS		/* The number of all registers.  */
+};
+
+/* Number of bytes of registers.  */
+#define NUMREGBYTES BFIN_NUM_REGS*4
+
+#define BREAKPOINT() asm("   EXCPT 2;");
+#define BREAK_INSTR_SIZE       2
+#define HW_BREAKPOINT_NUM		6
+
+/* Instruction watchpoint address control register bits mask */
+#define WPPWR		0x1
+#define WPIREN01	0x2
+#define WPIRINV01	0x4
+#define WPIAEN0		0x8
+#define WPIAEN1		0x10
+#define WPICNTEN0	0x20
+#define WPICNTEN1	0x40
+#define EMUSW0		0x80
+#define EMUSW1		0x100
+#define WPIREN23	0x200
+#define WPIRINV23	0x400
+#define WPIAEN2		0x800
+#define WPIAEN3		0x1000
+#define WPICNTEN2	0x2000
+#define WPICNTEN3	0x4000
+#define EMUSW2		0x8000
+#define EMUSW3		0x10000
+#define WPIREN45	0x20000
+#define WPIRINV45	0x40000
+#define WPIAEN4		0x80000
+#define WPIAEN5		0x100000
+#define WPICNTEN4	0x200000
+#define WPICNTEN5	0x400000
+#define EMUSW4		0x800000
+#define EMUSW5		0x1000000
+#define WPAND		0x2000000
+
+/* Data watchpoint address control register bits mask */
+#define WPDREN01	0x1
+#define WPDRINV01	0x2
+#define WPDAEN0		0x4
+#define WPDAEN1		0x8
+#define WPDCNTEN0	0x10
+#define WPDCNTEN1	0x20
+#define WPDSRC0		0xc0
+#define WPDACC0		0x300
+#define WPDSRC1		0xc00
+#define WPDACC1		0x3000
+
+/* Watchpoint status register bits mask */
+#define STATIA0		0x1
+#define STATIA1		0x2
+#define STATIA2		0x4
+#define STATIA3		0x8
+#define STATIA4		0x10
+#define STATIA5		0x20
+#define STATDA0		0x40
+#define STATDA1		0x80
+
+extern void kgdb_print(const char *fmt, ...);
+
+#endif