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Commit f0b5d12f authored by Mike Frysinger's avatar Mike Frysinger Committed by Bryan Wu
Browse files

Blackfin arch: allow people to select the feature that is unavailable to the kernel 



 - allow people to select the feature that is unavailable to the kernel: NMI, JTAG, or CYCLES.
 - change default NMI handler to simply dump hardware trace buffer.
 - remove default NMI handler completely as calling into kernel code is not safe
   move example handler to wiki so people dont haphazardly copy and paste this stuff thinking its safe

Signed-off-by: default avatarMike Frysinger <michael.frysinger@analog.com>
Signed-off-by: default avatarBryan Wu <bryan.wu@analog.com>
parent 0174dd59

arch/blackfin/Kconfig

+46 −0
Original line number Diff line number Diff line
@@ -521,6 +521,52 @@ config BFIN_IDLE_LED_NUM 
	help

	  Select the LED (marked on the board) for you to blink.



choice

	prompt "Blackfin Exception Scratch Register"

	default BFIN_SCRATCH_REG_RETN

	help

	  Select the resource to reserve for the Exception handler:

	    - RETN: Non-Maskable Interrupt (NMI)

	    - RETE: Exception Return (JTAG/ICE)

	    - CYCLES: Performance counter



	  If you are unsure, please select "RETN".



config BFIN_SCRATCH_REG_RETN

	bool "RETN"

	help

	  Use the RETN register in the Blackfin exception handler

	  as a stack scratch register.  This means you cannot

	  safely use NMI on the Blackfin while running Linux, but

	  you can debug the system with a JTAG ICE and use the

	  CYCLES performance registers.



	  If you are unsure, please select "RETN".



config BFIN_SCRATCH_REG_RETE

	bool "RETE"

	help

	  Use the RETE register in the Blackfin exception handler

	  as a stack scratch register.  This means you cannot

	  safely use a JTAG ICE while debugging a Blackfin board,

	  but you can safely use the CYCLES performance registers

	  and the NMI.



	  If you are unsure, please select "RETN".



config BFIN_SCRATCH_REG_CYCLES

	bool "CYCLES"

	help

	  Use the CYCLES register in the Blackfin exception handler

	  as a stack scratch register.  This means you cannot

	  safely use the CYCLES performance registers on a Blackfin

	  board at anytime, but you can debug the system with a JTAG

	  ICE and use the NMI.



	  If you are unsure, please select "RETN".



endchoice



#

# Sorry - but you need to put the hex address here -

#

arch/blackfin/kernel/irqchip.c

+1 −2
Original line number Diff line number Diff line
@@ -98,9 +98,8 @@ int show_interrupts(struct seq_file *p, void *v) 
 */



#ifdef CONFIG_DO_IRQ_L1

asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)__attribute__((l1_text));

__attribute__((l1_text))

#endif



asmlinkage void asm_do_IRQ(unsigned int irq, struct pt_regs *regs)

{

	struct pt_regs *old_regs;

arch/blackfin/mach-bf533/head.S

+6 −4
Original line number Diff line number Diff line
@@ -53,10 +53,12 @@ __INIT 
ENTRY(__start)

	/* R0: argument of command line string, passed from uboot, save it */

	R7 = R0;

	/* Set the SYSCFG register:

	 * Enable Cycle Counter and Nesting Of Interrupts (3rd Bit)

	 */

	R0 = 0x36;

	/* Enable Cycle Counter and Nesting Of Interrupts */

#ifdef CONFIG_BFIN_SCRATCH_REG_CYCLES

	R0 = SYSCFG_SNEN;

#else

	R0 = SYSCFG_SNEN | SYSCFG_CCEN;

#endif

	SYSCFG = R0;

	R0 = 0;

arch/blackfin/mach-bf537/head.S

+6 −4
Original line number Diff line number Diff line
@@ -51,10 +51,12 @@ __INIT 
ENTRY(__start)

	/* R0: argument of command line string, passed from uboot, save it */

	R7 = R0;

	/* Set the SYSCFG register:

	 * Enable Cycle Counter and Nesting Of Interrupts (3rd Bit)

	 */

	R0 = 0x36;

	/* Enable Cycle Counter and Nesting Of Interrupts */

#ifdef CONFIG_BFIN_SCRATCH_REG_CYCLES

	R0 = SYSCFG_SNEN;

#else

	R0 = SYSCFG_SNEN | SYSCFG_CCEN;

#endif

	SYSCFG = R0;

	R0 = 0;

arch/blackfin/mach-bf548/head.S

+7 −3
Original line number Diff line number Diff line
@@ -50,9 +50,13 @@ ENTRY(__start) 
ENTRY(__stext)

	/* R0: argument of command line string, passed from uboot, save it */

	R7 = R0;

	/* Set the SYSCFG register */

	R0 = 0x36;

	SYSCFG = R0;   /*Enable Cycle Counter and Nesting Of Interrupts(3rd Bit)*/

	/* Enable Cycle Counter and Nesting Of Interrupts */

#ifdef CONFIG_BFIN_SCRATCH_REG_CYCLES

	R0 = SYSCFG_SNEN;

#else

	R0 = SYSCFG_SNEN | SYSCFG_CCEN;

#endif

	SYSCFG = R0;

	R0 = 0;



	/* Clear Out All the data and pointer  Registers*/