Blackfin arch: kgdb specific code

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

6 files changed, 866 insertions, 1 deletions

diff --git a/Documentation/blackfin/kgdb.txt b/Documentation/blackfin/kgdb.txt
new file mode 100644
index 000000000000..84f6a484ae9a
--- /dev/null
+++ b/Documentation/blackfin/kgdb.txt
@@ -0,0 +1,155 @@
+			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 $(BINROOT)/bfin-elf-gdb.
+
+2. Apply this patch to the 2.6.x kernel.  Select the menuconfig option under
+   "Kernel hacking" -> "Kernel debugging" -> "KGDB: kernel debug with remote gdb".
+   With this selected, option "Full Symbolic/Source Debugging support" and 
+   "Compile the kernel with frame pointers" are also selected.
+
+3. Select option "KGDB: connect over UART".  Set "KGDB: UART port number" to console.
+   Don't forget to change the mode of blackfin serial driver to PIO.
+   Otherwise kgdb works incorrectly on UART.
+ 
+4. If you want connect to kgdb when the kernel boots, enable
+   "KGDB: Wait for gdb connection early" 
+
+5. Connect minicom to the serial port and boot the kernel image. 
+
+6. (Optional) Ask target to wait for gdb connection by entering Ctrl+A. In minicom, you should enter Ctrl+A+A.
+
+7. Start GDB client "bfin-elf-gdb vmlinux".
+
+8. Set the baud rate in GDB "(gdb) set remotebaud 57600".
+
+9. Connect to the target "(gdb) target remote /dev/ttyS0".
+
+10. Set software breakpoint "(gdb) break sys_open".
+
+11. Continue "(gdb) c". Then enter Ctrl+C twice to stop GDB connection.
+
+12. Run ls in the target console "/> ls". Dummy string can be seen on the console.
+
+13. Then connect the gdb to target again. "(gdb) target remote /dev/ttyS0".
+    Now you will find a breakpoint is hit. "Breakpoint 1: sys_open(..."
+
+14. All other operations are the same as that in KGDB over Ethernet.  The only
+    difference is that after continue command in GDB, please stop GDB
+    connection by 2 "Ctrl+C"s and connect again after breakpoints are hit or
+    Ctrl+A is entered.
diff --git a/arch/blackfin/kernel/Makefile b/arch/blackfin/kernel/Makefile
index b7b6de824011..6fac57f6ce06 100644
--- a/arch/blackfin/kernel/Makefile
+++ b/arch/blackfin/kernel/Makefile
@@ -14,3 +14,4 @@ obj-$(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
diff --git a/arch/blackfin/kernel/kgdb.c b/arch/blackfin/kernel/kgdb.c
new file mode 100644
index 000000000000..a9c15515bfd7
--- /dev/null
+++ b/arch/blackfin/kernel/kgdb.c
@@ -0,0 +1,421 @@
+/*
+ * File:         arch/blackfin/kernel/kgdb.c
+ * 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
+ */
+
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/spinlock.h>
+#include <linux/delay.h>
+#include <linux/ptrace.h>		/* for linux pt_regs struct */
+#include <linux/kgdb.h>
+#include <linux/console.h>
+#include <linux/init.h>
+#include <linux/debugger.h>
+#include <linux/errno.h>
+#include <linux/irq.h>
+#include <asm/system.h>
+#include <asm/traps.h>
+#include <asm/blackfin.h>
+
+/* Put the error code here just in case the user cares.  */
+int gdb_bf533errcode;
+/* Likewise, the vector number here (since GDB only gets the signal
+   number through the usual means, and that's not very specific).  */
+int gdb_bf533vector = -1;
+
+#if KGDB_MAX_NO_CPUS != 8
+#error change the definition of slavecpulocks
+#endif
+
+void regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+	gdb_regs[BFIN_R0] = regs->r0;
+	gdb_regs[BFIN_R1] = regs->r1;
+	gdb_regs[BFIN_R2] = regs->r2;
+	gdb_regs[BFIN_R3] = regs->r3;
+	gdb_regs[BFIN_R4] = regs->r4;
+	gdb_regs[BFIN_R5] = regs->r5;
+	gdb_regs[BFIN_R6] = regs->r6;
+	gdb_regs[BFIN_R7] = regs->r7;
+	gdb_regs[BFIN_P0] = regs->p0;
+	gdb_regs[BFIN_P1] = regs->p1;
+	gdb_regs[BFIN_P2] = regs->p2;
+	gdb_regs[BFIN_P3] = regs->p3;
+	gdb_regs[BFIN_P4] = regs->p4;
+	gdb_regs[BFIN_P5] = regs->p5;
+	gdb_regs[BFIN_SP] = regs->reserved;
+	gdb_regs[BFIN_FP] = regs->fp;
+	gdb_regs[BFIN_I0] = regs->i0;
+	gdb_regs[BFIN_I1] = regs->i1;
+	gdb_regs[BFIN_I2] = regs->i2;
+	gdb_regs[BFIN_I3] = regs->i3;
+	gdb_regs[BFIN_M0] = regs->m0;
+	gdb_regs[BFIN_M1] = regs->m1;
+	gdb_regs[BFIN_M2] = regs->m2;
+	gdb_regs[BFIN_M3] = regs->m3;
+	gdb_regs[BFIN_B0] = regs->b0;
+	gdb_regs[BFIN_B1] = regs->b1;
+	gdb_regs[BFIN_B2] = regs->b2;
+	gdb_regs[BFIN_B3] = regs->b3;
+	gdb_regs[BFIN_L0] = regs->l0;
+	gdb_regs[BFIN_L1] = regs->l1;
+	gdb_regs[BFIN_L2] = regs->l2;
+	gdb_regs[BFIN_L3] = regs->l3;
+	gdb_regs[BFIN_A0_DOT_X] = regs->a0x;
+	gdb_regs[BFIN_A0_DOT_W] = regs->a0w;
+	gdb_regs[BFIN_A1_DOT_X] = regs->a1x;
+	gdb_regs[BFIN_A1_DOT_W] = regs->a1w;
+	gdb_regs[BFIN_ASTAT] = regs->astat;
+	gdb_regs[BFIN_RETS] = regs->rets;
+	gdb_regs[BFIN_LC0] = regs->lc0;
+	gdb_regs[BFIN_LT0] = regs->lt0;
+	gdb_regs[BFIN_LB0] = regs->lb0;
+	gdb_regs[BFIN_LC1] = regs->lc1;
+	gdb_regs[BFIN_LT1] = regs->lt1;
+	gdb_regs[BFIN_LB1] = regs->lb1;
+	gdb_regs[BFIN_CYCLES] = 0;
+	gdb_regs[BFIN_CYCLES2] = 0;
+	gdb_regs[BFIN_USP] = regs->usp;
+	gdb_regs[BFIN_SEQSTAT] = regs->seqstat;
+	gdb_regs[BFIN_SYSCFG] = regs->syscfg;
+	gdb_regs[BFIN_RETI] = regs->pc;
+	gdb_regs[BFIN_RETX] = regs->retx;
+	gdb_regs[BFIN_RETN] = regs->retn;
+	gdb_regs[BFIN_RETE] = regs->rete;
+	gdb_regs[BFIN_PC] = regs->pc;
+	gdb_regs[BFIN_CC] = 0;
+	gdb_regs[BFIN_EXTRA1] = 0;
+	gdb_regs[BFIN_EXTRA2] = 0;
+	gdb_regs[BFIN_EXTRA3] = 0;
+	gdb_regs[BFIN_IPEND] = regs->ipend;
+}
+
+/*
+ * Extracts ebp, esp and eip values understandable by gdb from the values
+ * saved by switch_to.
+ * thread.esp points to ebp. flags and ebp are pushed in switch_to hence esp
+ * prior to entering switch_to is 8 greater then the value that is saved.
+ * If switch_to changes, change following code appropriately.
+ */
+void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
+{
+	gdb_regs[BFIN_SP] = p->thread.ksp;
+	gdb_regs[BFIN_PC] = p->thread.pc;
+	gdb_regs[BFIN_SEQSTAT] = p->thread.seqstat;
+}
+
+void gdb_regs_to_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+	regs->r0 = gdb_regs[BFIN_R0];
+	regs->r1 = gdb_regs[BFIN_R1];
+	regs->r2 = gdb_regs[BFIN_R2];
+	regs->r3 = gdb_regs[BFIN_R3];
+	regs->r4 = gdb_regs[BFIN_R4];
+	regs->r5 = gdb_regs[BFIN_R5];
+	regs->r6 = gdb_regs[BFIN_R6];
+	regs->r7 = gdb_regs[BFIN_R7];
+	regs->p0 = gdb_regs[BFIN_P0];
+	regs->p1 = gdb_regs[BFIN_P1];
+	regs->p2 = gdb_regs[BFIN_P2];
+	regs->p3 = gdb_regs[BFIN_P3];
+	regs->p4 = gdb_regs[BFIN_P4];
+	regs->p5 = gdb_regs[BFIN_P5];
+	regs->fp = gdb_regs[BFIN_FP];
+	regs->i0 = gdb_regs[BFIN_I0];
+	regs->i1 = gdb_regs[BFIN_I1];
+	regs->i2 = gdb_regs[BFIN_I2];
+	regs->i3 = gdb_regs[BFIN_I3];
+	regs->m0 = gdb_regs[BFIN_M0];
+	regs->m1 = gdb_regs[BFIN_M1];
+	regs->m2 = gdb_regs[BFIN_M2];
+	regs->m3 = gdb_regs[BFIN_M3];
+	regs->b0 = gdb_regs[BFIN_B0];
+	regs->b1 = gdb_regs[BFIN_B1];
+	regs->b2 = gdb_regs[BFIN_B2];
+	regs->b3 = gdb_regs[BFIN_B3];
+	regs->l0 = gdb_regs[BFIN_L0];
+	regs->l1 = gdb_regs[BFIN_L1];
+	regs->l2 = gdb_regs[BFIN_L2];
+	regs->l3 = gdb_regs[BFIN_L3];
+	regs->a0x = gdb_regs[BFIN_A0_DOT_X];
+	regs->a0w = gdb_regs[BFIN_A0_DOT_W];
+	regs->a1x = gdb_regs[BFIN_A1_DOT_X];
+	regs->a1w = gdb_regs[BFIN_A1_DOT_W];
+	regs->rets = gdb_regs[BFIN_RETS];
+	regs->lc0 = gdb_regs[BFIN_LC0];
+	regs->lt0 = gdb_regs[BFIN_LT0];
+	regs->lb0 = gdb_regs[BFIN_LB0];
+	regs->lc1 = gdb_regs[BFIN_LC1];
+	regs->lt1 = gdb_regs[BFIN_LT1];
+	regs->lb1 = gdb_regs[BFIN_LB1];
+	regs->usp = gdb_regs[BFIN_USP];
+	regs->syscfg = gdb_regs[BFIN_SYSCFG];
+	regs->retx = gdb_regs[BFIN_PC];
+	regs->retn = gdb_regs[BFIN_RETN];
+	regs->rete = gdb_regs[BFIN_RETE];
+	regs->pc = gdb_regs[BFIN_PC];
+
+#if 0				/* can't change these */
+	regs->astat = gdb_regs[BFIN_ASTAT];
+	regs->seqstat = gdb_regs[BFIN_SEQSTAT];
+	regs->ipend = gdb_regs[BFIN_IPEND];
+#endif
+}
+
+struct hw_breakpoint {
+	unsigned int occupied:1;
+	unsigned int skip:1;
+	unsigned int enabled:1;
+	unsigned int type:1;
+	unsigned int dataacc:2;
+	unsigned short count;
+	unsigned int addr;
+} breakinfo[HW_BREAKPOINT_NUM];
+
+int kgdb_arch_init(void)
+{
+	kgdb_remove_all_hw_break();
+	return 0;
+}
+
+int kgdb_set_hw_break(unsigned long addr)
+{
+	int breakno;
+	for (breakno = 0; breakno < HW_BREAKPOINT_NUM; breakno++)
+		if (!breakinfo[breakno].occupied) {
+			breakinfo[breakno].occupied = 1;
+			breakinfo[breakno].enabled = 1;
+			breakinfo[breakno].type = 1;
+			breakinfo[breakno].addr = addr;
+			return 0;
+		}
+
+	return -ENOSPC;
+}
+
+int kgdb_remove_hw_break(unsigned long addr)
+{
+	int breakno;
+	for (breakno = 0; breakno < HW_BREAKPOINT_NUM; breakno++)
+		if (breakinfo[breakno].addr == addr)
+			memset(&(breakinfo[breakno]), 0, sizeof(struct hw_breakpoint));
+
+	return 0;
+}
+
+void kgdb_remove_all_hw_break(void)
+{
+	memset(breakinfo, 0, sizeof(struct hw_breakpoint)*8);
+}
+
+/*
+void kgdb_show_info(void)
+{
+	printk(KERN_DEBUG "hwd: wpia0=0x%x, wpiacnt0=%d, wpiactl=0x%x, wpstat=0x%x\n",
+		bfin_read_WPIA0(), bfin_read_WPIACNT0(),
+		bfin_read_WPIACTL(), bfin_read_WPSTAT());
+}
+*/
+
+void kgdb_correct_hw_break(void)
+{
+	int breakno;
+	int correctit;
+	uint32_t wpdactl = bfin_read_WPDACTL();
+
+	correctit = 0;
+	for (breakno = 0; breakno < HW_BREAKPOINT_NUM; breakno++) {
+		if (breakinfo[breakno].type == 1) {
+			switch (breakno) {
+			case 0:
+				if (breakinfo[breakno].enabled && !(wpdactl & WPIAEN0)) {
+					correctit = 1;
+					wpdactl &= ~(WPIREN01|EMUSW0);
+					wpdactl |= WPIAEN0|WPICNTEN0;
+					bfin_write_WPIA0(breakinfo[breakno].addr);
+					bfin_write_WPIACNT0(breakinfo[breakno].skip);
+				} else if (!breakinfo[breakno].enabled && (wpdactl & WPIAEN0)) {
+					correctit = 1;
+					wpdactl &= ~WPIAEN0;
+				}
+				break;
+
+			case 1:
+				if (breakinfo[breakno].enabled && !(wpdactl & WPIAEN1)) {
+					correctit = 1;
+					wpdactl &= ~(WPIREN01|EMUSW1);
+					wpdactl |= WPIAEN1|WPICNTEN1;
+					bfin_write_WPIA1(breakinfo[breakno].addr);
+					bfin_write_WPIACNT1(breakinfo[breakno].skip);
+				} else if (!breakinfo[breakno].enabled && (wpdactl & WPIAEN1)) {
+					correctit = 1;
+					wpdactl &= ~WPIAEN1;
+				}
+				break;
+
+			case 2:
+				if (breakinfo[breakno].enabled && !(wpdactl & WPIAEN2)) {
+					correctit = 1;
+					wpdactl &= ~(WPIREN23|EMUSW2);
+					wpdactl |= WPIAEN2|WPICNTEN2;
+					bfin_write_WPIA2(breakinfo[breakno].addr);
+					bfin_write_WPIACNT2(breakinfo[breakno].skip);
+				} else if (!breakinfo[breakno].enabled && (wpdactl & WPIAEN2)) {
+					correctit = 1;
+					wpdactl &= ~WPIAEN2;
+				}
+				break;
+
+			case 3:
+				if (breakinfo[breakno].enabled && !(wpdactl & WPIAEN3)) {
+					correctit = 1;
+					wpdactl &= ~(WPIREN23|EMUSW3);
+					wpdactl |= WPIAEN3|WPICNTEN3;
+					bfin_write_WPIA3(breakinfo[breakno].addr);
+					bfin_write_WPIACNT3(breakinfo[breakno].skip);
+				} else if (!breakinfo[breakno].enabled && (wpdactl & WPIAEN3)) {
+					correctit = 1;
+					wpdactl &= ~WPIAEN3;
+				}
+				break;
+			case 4:
+				if (breakinfo[breakno].enabled && !(wpdactl & WPIAEN4)) {
+					correctit = 1;
+					wpdactl &= ~(WPIREN45|EMUSW4);
+					wpdactl |= WPIAEN4|WPICNTEN4;
+					bfin_write_WPIA4(breakinfo[breakno].addr);
+					bfin_write_WPIACNT4(breakinfo[breakno].skip);
+				} else if (!breakinfo[breakno].enabled && (wpdactl & WPIAEN4)) {
+					correctit = 1;
+					wpdactl &= ~WPIAEN4;
+				}
+				break;
+			case 5:
+				if (breakinfo[breakno].enabled && !(wpdactl & WPIAEN5)) {
+					correctit = 1;
+					wpdactl &= ~(WPIREN45|EMUSW5);
+					wpdactl |= WPIAEN5|WPICNTEN5;
+					bfin_write_WPIA5(breakinfo[breakno].addr);
+					bfin_write_WPIACNT5(breakinfo[breakno].skip);
+				} else if (!breakinfo[breakno].enabled && (wpdactl & WPIAEN5)) {
+					correctit = 1;
+					wpdactl &= ~WPIAEN5;
+				}
+				break;
+			}
+		}
+	}
+	if (correctit) {
+		wpdactl &= ~WPAND;
+		wpdactl |= WPPWR;
+		/*printk("correct_hw_break: wpdactl=0x%x\n", wpdactl);*/
+		bfin_write_WPDACTL(wpdactl);
+		CSYNC();
+		/*kgdb_show_info();*/
+	}
+}
+
+void kgdb_disable_hw_debug(struct pt_regs *regs)
+{
+	/* Disable hardware debugging while we are in kgdb */
+	bfin_write_WPIACTL(bfin_read_WPIACTL() & ~0x1);
+	CSYNC();
+}
+
+void kgdb_post_master_code(struct pt_regs *regs, int eVector, int err_code)
+{
+	/* Master processor is completely in the debugger */
+	gdb_bf533vector = eVector;
+	gdb_bf533errcode = err_code;
+}
+
+int kgdb_arch_handle_exception(int exceptionVector, int signo,
+			       int err_code, char *remcom_in_buffer,
+			       char *remcom_out_buffer,
+			       struct pt_regs *linux_regs)
+{
+	long addr;
+	long breakno;
+	char *ptr;
+	int newPC;
+	int wp_status;
+
+	switch (remcom_in_buffer[0]) {
+	case 'c':
+	case 's':
+		if (kgdb_contthread && kgdb_contthread != current) {
+			strcpy(remcom_out_buffer, "E00");
+			break;
+		}
+
+		kgdb_contthread = NULL;
+
+		/* try to read optional parameter, pc unchanged if no parm */
+		ptr = &remcom_in_buffer[1];
+		if (kgdb_hex2long(&ptr, &addr)) {
+			linux_regs->retx = addr;
+		}
+		newPC = linux_regs->retx;
+
+		/* clear the trace bit */
+		linux_regs->syscfg &= 0xfffffffe;
+
+		/* set the trace bit if we're stepping */
+		if (remcom_in_buffer[0] == 's') {
+			linux_regs->syscfg |= 0x1;
+			debugger_step = 1;
+		}
+
+		wp_status = bfin_read_WPSTAT();
+		CSYNC();
+
+		if (exceptionVector == VEC_WATCH) {
+			for (breakno = 0; breakno < 6; ++breakno) {
+				if (wp_status & (1 << breakno)) {
+					breakinfo->skip = 1;
+					break;
+				}
+			}
+		}
+		kgdb_correct_hw_break();
+
+		bfin_write_WPSTAT(0);
+
+		return 0;
+	}			/* switch */
+	return -1;		/* this means that we do not want to exit from the handler */
+}
+
+struct kgdb_arch arch_kgdb_ops = {
+	.gdb_bpt_instr = {0xa1},
+	.flags = KGDB_HW_BREAKPOINT,
+};
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 315ea9916456..71a4ac53a7ef 100644
--- a/drivers/serial/Kconfig
+++ b/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.
diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
index 22569bd5d821..f7926dc7fa78 100644
--- a/drivers/serial/bfin_5xx.c
+++ b/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;
 }
 
diff --git a/include/asm-blackfin/kgdb.h b/include/asm-blackfin/kgdb.h
new file mode 100644
index 000000000000..532bd9052004
--- /dev/null
+++ b/include/asm-blackfin/kgdb.h
@@ -0,0 +1,183 @@
+/*
+ * 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