---

yaml
---
r: 74419
b: refs/heads/master
c: e252d4c
h: refs/heads/master
i:
  74417: 1d9efaa
  74415: 55499b8
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 008f6d2a2817b4a36d477fe969840bb0ef1351a8
+refs/heads/master: e252d4c362ad89c5b533833d9e7493c732215925

trunk/MAINTAINERS

@@ -440,7 +440,7 @@ S:	Maintained
 
 ARM/ATMEL AT91RM9200 ARM ARCHITECTURE
 P:      Andrew Victor
-M:      andrew@sanpeople.com
+M:      linux@maxim.org.za
 L:      linux-arm-kernel@lists.arm.linux.org.uk (subscribers-only)
 W:      http://maxim.org.za/at91_26.html
 S:      Maintained

trunk/arch/arm/common/uengine.c

@@ -374,8 +374,8 @@ static int set_initial_registers(int uengine, struct ixp2000_uengine_code *c)
 	u8 *ucode;
 	int i;
 
-	gpr_a = kmalloc(128 * sizeof(u32), GFP_KERNEL);
-	gpr_b = kmalloc(128 * sizeof(u32), GFP_KERNEL);
+	gpr_a = kzalloc(128 * sizeof(u32), GFP_KERNEL);
+	gpr_b = kzalloc(128 * sizeof(u32), GFP_KERNEL);
 	ucode = kmalloc(513 * 5, GFP_KERNEL);
 	if (gpr_a == NULL || gpr_b == NULL || ucode == NULL) {
 		kfree(ucode);
@@ -388,8 +388,6 @@ static int set_initial_registers(int uengine, struct ixp2000_uengine_code *c)
 	if (c->uengine_parameters & IXP2000_UENGINE_4_CONTEXTS)
 		per_ctx_regs = 32;
 
-	memset(gpr_a, 0, sizeof(gpr_a));
-	memset(gpr_b, 0, sizeof(gpr_b));
 	for (i = 0; i < 256; i++) {
 		struct ixp2000_reg_value *r = c->initial_reg_values + i;
 		u32 *bank;

trunk/arch/arm/kernel/entry-armv.S

@@ -339,16 +339,6 @@ __pabt_svc:
 	str	r1, [sp]		@ save the "real" r0 copied
 					@ from the exception stack
 
-#if __LINUX_ARM_ARCH__ < 6 && !defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG)
-#ifndef CONFIG_MMU
-#warning "NPTL on non MMU needs fixing"
-#else
-	@ make sure our user space atomic helper is aborted
-	cmp	r2, #TASK_SIZE
-	bichs	r3, r3, #PSR_Z_BIT
-#endif
-#endif
-
 	@
 	@ We are now ready to fill in the remaining blanks on the stack:
 	@
@@ -372,9 +362,25 @@ __pabt_svc:
 	zero_fp
 	.endm
 
+	.macro	kuser_cmpxchg_check
+#if __LINUX_ARM_ARCH__ < 6 && !defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG)
+#ifndef CONFIG_MMU
+#warning "NPTL on non MMU needs fixing"
+#else
+	@ Make sure our user space atomic helper is restarted
+	@ if it was interrupted in a critical region.  Here we
+	@ perform a quick test inline since it should be false
+	@ 99.9999% of the time.  The rest is done out of line.
+	cmp	r2, #TASK_SIZE
+	blhs	kuser_cmpxchg_fixup
+#endif
+#endif
+	.endm
+
 	.align	5
 __dabt_usr:
 	usr_entry
+	kuser_cmpxchg_check
 
 	@
 	@ Call the processor-specific abort handler:
@@ -404,6 +410,7 @@ __dabt_usr:
 	.align	5
 __irq_usr:
 	usr_entry
+	kuser_cmpxchg_check
 
 #ifdef CONFIG_TRACE_IRQFLAGS
 	bl	trace_hardirqs_off
@@ -446,9 +453,9 @@ __und_usr:
 	@
 	@  r0 - instruction
 	@
-1:	ldrt	r0, [r4]
 	adr	r9, ret_from_exception
 	adr	lr, __und_usr_unknown
+1:	ldrt	r0, [r4]
 	@
 	@ fallthrough to call_fpe
 	@
@@ -669,7 +676,7 @@ __kuser_helper_start:
  *
  * Clobbered:
  *
- *	the Z flag might be lost
+ *	none
  *
  * Definition and user space usage example:
  *
@@ -730,9 +737,6 @@ __kuser_memory_barrier:				@ 0xffff0fa0
  *
  *    - This routine already includes memory barriers as needed.
  *
- *    - A failure might be transient, i.e. it is possible, although unlikely,
- *      that "failure" be returned even if *ptr == oldval.
- *
  * For example, a user space atomic_add implementation could look like this:
  *
  * #define atomic_add(ptr, val) \
@@ -769,46 +773,62 @@ __kuser_cmpxchg:				@ 0xffff0fc0
 
 #elif __LINUX_ARM_ARCH__ < 6
 
+#ifdef CONFIG_MMU
+
 	/*
-	 * Theory of operation:
-	 *
-	 * We set the Z flag before loading oldval. If ever an exception
-	 * occurs we can not be sure the loaded value will still be the same
-	 * when the exception returns, therefore the user exception handler
-	 * will clear the Z flag whenever the interrupted user code was
-	 * actually from the kernel address space (see the usr_entry macro).
-	 *
-	 * The post-increment on the str is used to prevent a race with an
-	 * exception happening just after the str instruction which would
-	 * clear the Z flag although the exchange was done.
+	 * The only thing that can break atomicity in this cmpxchg
+	 * implementation is either an IRQ or a data abort exception
+	 * causing another process/thread to be scheduled in the middle
+	 * of the critical sequence.  To prevent this, code is added to
+	 * the IRQ and data abort exception handlers to set the pc back
+	 * to the beginning of the critical section if it is found to be
+	 * within that critical section (see kuser_cmpxchg_fixup).
 	 */
-#ifdef CONFIG_MMU
-	teq	ip, ip			@ set Z flag
-	ldr	ip, [r2]		@ load current val
-	add	r3, r2, #1		@ prepare store ptr
-	teqeq	ip, r0			@ compare with oldval if still allowed
-	streq	r1, [r3, #-1]!		@ store newval if still allowed
-	subs	r0, r2, r3		@ if r2 == r3 the str occured
+1:	ldr	r3, [r2]			@ load current val
+	subs	r3, r3, r0			@ compare with oldval
+2:	streq	r1, [r2]			@ store newval if eq
+	rsbs	r0, r3, #0			@ set return val and C flag
+	usr_ret	lr
+
+	.text
+kuser_cmpxchg_fixup:
+	@ Called from kuser_cmpxchg_check macro.
+	@ r2 = address of interrupted insn (must be preserved).
+	@ sp = saved regs. r7 and r8 are clobbered.
+	@ 1b = first critical insn, 2b = last critical insn.
+	@ If r2 >= 1b and r2 <= 2b then saved pc_usr is set to 1b.
+	mov	r7, #0xffff0fff
+	sub	r7, r7, #(0xffff0fff - (0xffff0fc0 + (1b - __kuser_cmpxchg)))
+	subs	r8, r2, r7
+	rsbcss	r8, r8, #(2b - 1b)
+	strcs	r7, [sp, #S_PC]
+	mov	pc, lr
+	.previous
+
 #else
 #warning "NPTL on non MMU needs fixing"
 	mov	r0, #-1
 	adds	r0, r0, #0
-#endif
 	usr_ret	lr
+#endif
 
 #else
 
 #ifdef CONFIG_SMP
 	mcr	p15, 0, r0, c7, c10, 5	@ dmb
 #endif
-	ldrex	r3, [r2]
+1:	ldrex	r3, [r2]
 	subs	r3, r3, r0
 	strexeq	r3, r1, [r2]
+	teqeq	r3, #1
+	beq	1b
 	rsbs	r0, r3, #0
+	/* beware -- each __kuser slot must be 8 instructions max */
 #ifdef CONFIG_SMP
-	mcr	p15, 0, r0, c7, c10, 5	@ dmb
-#endif
+	b	__kuser_memory_barrier
+#else
 	usr_ret	lr
+#endif
 
 #endif
 
@@ -829,7 +849,7 @@ __kuser_cmpxchg:				@ 0xffff0fc0
  *
  * Clobbered:
  *
- *	the Z flag might be lost
+ *	none
  *
  * Definition and user space usage example:
  *

trunk/arch/arm/kernel/traps.c

@@ -327,7 +327,7 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 		if ((instr & hook->instr_mask) == hook->instr_val &&
 		    (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) {
 			if (hook->fn(regs, instr) == 0) {
-				spin_unlock_irq(&undef_lock);
+				spin_unlock_irqrestore(&undef_lock, flags);
 				return;
 			}
 		}
@@ -509,7 +509,7 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs)
 	 * existence.  Don't ever use this from user code.
 	 */
 	case 0xfff0:
-	{
+	for (;;) {
 		extern void do_DataAbort(unsigned long addr, unsigned int fsr,
 					 struct pt_regs *regs);
 		unsigned long val;
@@ -545,7 +545,6 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs)
 		up_read(&mm->mmap_sem);
 		/* simulate a write access fault */
 		do_DataAbort(addr, 15 + (1 << 11), regs);
-		return -1;
 	}
 #endif
 

trunk/arch/arm/mach-at91/at91rm9200_devices.c

@@ -14,6 +14,7 @@
 #include <asm/mach/map.h>
 
 #include <linux/platform_device.h>
+#include <linux/i2c-gpio.h>
 
 #include <asm/arch/board.h>
 #include <asm/arch/gpio.h>
@@ -435,7 +436,40 @@ void __init at91_add_device_nand(struct at91_nand_data *data) {}
  *  TWI (i2c)
  * -------------------------------------------------------------------- */
 
-#if defined(CONFIG_I2C_AT91) || defined(CONFIG_I2C_AT91_MODULE)
+/*
+ * Prefer the GPIO code since the TWI controller isn't robust
+ * (gets overruns and underruns under load) and can only issue
+ * repeated STARTs in one scenario (the driver doesn't yet handle them).
+ */
+#if defined(CONFIG_I2C_GPIO) || defined(CONFIG_I2C_GPIO_MODULE)
+
+static struct i2c_gpio_platform_data pdata = {
+	.sda_pin		= AT91_PIN_PA25,
+	.sda_is_open_drain	= 1,
+	.scl_pin		= AT91_PIN_PA26,
+	.scl_is_open_drain	= 1,
+	.udelay			= 2,		/* ~100 kHz */
+};
+
+static struct platform_device at91rm9200_twi_device = {
+	.name			= "i2c-gpio",
+	.id			= -1,
+	.dev.platform_data	= &pdata,
+};
+
+void __init at91_add_device_i2c(struct i2c_board_info *devices, int nr_devices)
+{
+	at91_set_GPIO_periph(AT91_PIN_PA25, 1);		/* TWD (SDA) */
+	at91_set_multi_drive(AT91_PIN_PA25, 1);
+
+	at91_set_GPIO_periph(AT91_PIN_PA26, 1);		/* TWCK (SCL) */
+	at91_set_multi_drive(AT91_PIN_PA26, 1);
+
+	i2c_register_board_info(0, devices, nr_devices);
+	platform_device_register(&at91rm9200_twi_device);
+}
+
+#elif defined(CONFIG_I2C_AT91) || defined(CONFIG_I2C_AT91_MODULE)
 
 static struct resource twi_resources[] = {
 	[0] = {
@@ -457,7 +491,7 @@ static struct platform_device at91rm9200_twi_device = {
 	.num_resources	= ARRAY_SIZE(twi_resources),
 };
 
-void __init at91_add_device_i2c(void)
+void __init at91_add_device_i2c(struct i2c_board_info *devices, int nr_devices)
 {
 	/* pins used for TWI interface */
 	at91_set_A_periph(AT91_PIN_PA25, 0);		/* TWD */
@@ -466,10 +500,11 @@ void __init at91_add_device_i2c(void)
 	at91_set_A_periph(AT91_PIN_PA26, 0);		/* TWCK */
 	at91_set_multi_drive(AT91_PIN_PA26, 1);
 
+	i2c_register_board_info(0, devices, nr_devices);
 	platform_device_register(&at91rm9200_twi_device);
 }
 #else
-void __init at91_add_device_i2c(void) {}
+void __init at91_add_device_i2c(struct i2c_board_info *devices, int nr_devices) {}
 #endif
 
 

trunk/arch/arm/mach-at91/at91sam9260_devices.c

@@ -13,6 +13,7 @@
 #include <asm/mach/map.h>
 
 #include <linux/platform_device.h>
+#include <linux/i2c-gpio.h>
 
 #include <asm/arch/board.h>
 #include <asm/arch/gpio.h>
@@ -352,7 +353,41 @@ void __init at91_add_device_nand(struct at91_nand_data *data) {}
  *  TWI (i2c)
  * -------------------------------------------------------------------- */
 
-#if defined(CONFIG_I2C_AT91) || defined(CONFIG_I2C_AT91_MODULE)
+/*
+ * Prefer the GPIO code since the TWI controller isn't robust
+ * (gets overruns and underruns under load) and can only issue
+ * repeated STARTs in one scenario (the driver doesn't yet handle them).
+ */
+
+#if defined(CONFIG_I2C_GPIO) || defined(CONFIG_I2C_GPIO_MODULE)
+
+static struct i2c_gpio_platform_data pdata = {
+	.sda_pin		= AT91_PIN_PA23,
+	.sda_is_open_drain	= 1,
+	.scl_pin		= AT91_PIN_PA24,
+	.scl_is_open_drain	= 1,
+	.udelay			= 2,		/* ~100 kHz */
+};
+
+static struct platform_device at91sam9260_twi_device = {
+	.name			= "i2c-gpio",
+	.id			= -1,
+	.dev.platform_data	= &pdata,
+};
+
+void __init at91_add_device_i2c(struct i2c_board_info *devices, int nr_devices)
+{
+	at91_set_GPIO_periph(AT91_PIN_PA23, 1);		/* TWD (SDA) */
+	at91_set_multi_drive(AT91_PIN_PA23, 1);
+
+	at91_set_GPIO_periph(AT91_PIN_PA24, 1);		/* TWCK (SCL) */
+	at91_set_multi_drive(AT91_PIN_PA24, 1);
+
+	i2c_register_board_info(0, devices, nr_devices);
+	platform_device_register(&at91sam9260_twi_device);
+}
+
+#elif defined(CONFIG_I2C_AT91) || defined(CONFIG_I2C_AT91_MODULE)
 
 static struct resource twi_resources[] = {
 	[0] = {
@@ -374,7 +409,7 @@ static struct platform_device at91sam9260_twi_device = {
 	.num_resources	= ARRAY_SIZE(twi_resources),
 };
 
-void __init at91_add_device_i2c(void)
+void __init at91_add_device_i2c(struct i2c_board_info *devices, int nr_devices)
 {
 	/* pins used for TWI interface */
 	at91_set_A_periph(AT91_PIN_PA23, 0);		/* TWD */
@@ -383,10 +418,11 @@ void __init at91_add_device_i2c(void)
 	at91_set_A_periph(AT91_PIN_PA24, 0);		/* TWCK */
 	at91_set_multi_drive(AT91_PIN_PA24, 1);
 
+	i2c_register_board_info(0, devices, nr_devices);
 	platform_device_register(&at91sam9260_twi_device);
 }
 #else
-void __init at91_add_device_i2c(void) {}
+void __init at91_add_device_i2c(struct i2c_board_info *devices, int nr_devices) {}
 #endif