More Cortex-M0/NUC120 fixes

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5670 42af7a65-404d-4744-a932-0658087f49c3

7 files changed, 70 insertions, 50 deletions

diff --git a/nuttx/arch/arm/src/armv6-m/exc_return.h b/nuttx/arch/arm/src/armv6-m/exc_return.h
index e779df505..4a7829428 100644
--- a/nuttx/arch/arm/src/armv6-m/exc_return.h
+++ b/nuttx/arch/arm/src/armv6-m/exc_return.h
@@ -50,18 +50,18 @@
  * exception mechanism relies on this value to detect when the processor has
  * completed an exception handler.
  *
- * Bits [31:28] of an EXC_RETURN value are always 1.  When the processor loads a
+ * Bits [31:4] of an EXC_RETURN value are always 1.  When the processor loads a
  * value matching this pattern to the PC it detects that the operation is a not
  * a normal branch operation and instead, that the exception is complete.
  * Therefore, it starts the exception return sequence.
  *
- * Bits[4:0] of the EXC_RETURN value indicate the required return stack and eventual
+ * Bits[3:0] of the EXC_RETURN value indicate the required return stack and eventual
  * processor mode.  The remaining bits of the EXC_RETURN value should be set to 1.
  */
 
 /* EXC_RETURN_BASE: Bits that are always set in an EXC_RETURN value. */
 
-#define EXC_RETURN_BASE          0xffffffe1
+#define EXC_RETURN_BASE          0xfffffff1
 
 /* EXC_RETURN_PROCESS_STACK: The exception saved (and will restore) the hardware
  * context using the process stack pointer (if not set, the context was saved
@@ -72,20 +72,12 @@
 #define EXC_RETURN_PROCESS_STACK (1 << EXC_RETURN_PROCESS_BITNO)
 
 /* EXC_RETURN_THREAD_MODE: The exception will return to thread mode (if not set,
- * return stays in handler mode)
+ * return stays in handler mode).
  */
 
 #define EXC_RETURN_THREAD_BITNO  (3)
 #define EXC_RETURN_THREAD_MODE   (1 << EXC_RETURN_THREAD_BITNO)
 
-/* EXC_RETURN_STD_CONTEXT: The state saved on the stack does not include the
- * volatile FP registers and FPSCR.  If this bit is clear, the state does include
- * these registers.
- */
-
-#define EXC_RETURN_STD_BITNO     (4)
-#define EXC_RETURN_STD_CONTEXT   (1 << EXC_RETURN_STD_BITNO)
-
 /* EXC_RETURN_HANDLER: Return to handler mode. Exception return gets state from
  * the main stack. Execution uses MSP after return.
  */
@@ -104,15 +96,7 @@
 
 #define EXC_RETURN_UNPRIVTHR     0xfffffffd
 
-/* In the kernel build is not selected, then all threads run in privileged thread
- * mode.
- */
-
-#ifdef CONFIG_NUTTX_KERNEL
-#  define EXC_RETURN             0xfffffff9
-#endif
-
-/************************Th************************************************************
+/************************************************************************************
  * Inline Functions
  ************************************************************************************/
 
diff --git a/nuttx/arch/arm/src/armv6-m/up_exception.S b/nuttx/arch/arm/src/armv6-m/up_exception.S
index 33f89b3b1..6a74d4dd6 100644
--- a/nuttx/arch/arm/src/armv6-m/up_exception.S
+++ b/nuttx/arch/arm/src/armv6-m/up_exception.S
@@ -93,7 +93,7 @@ exception_common:
 	 */
 
 	mov		r0, r14					/* Copy high register to low register */
-	lsl		r1, r0, #(31 - EXC_RETURN_PROCESS_BITNO)	/* Move to bit 31 */
+	lsl		r0, #(31 - EXC_RETURN_PROCESS_BITNO)	/* Move to bit 31 */
 	bmi		1f						/* Test bit 31 */
 	mrs		r1, msp					/* R1=The main stack pointer */
 	b		2f
@@ -191,7 +191,7 @@ exception_common:
 	/* Recover R8-R11 and EXEC_RETURN (5 registers) */
 
 	mov		r2, #(4*REG_R8)			/* R2=Offset to R8 storage */
-	sub		r0, r1, r2				/* R0=Address of R8 storage */
+	add		r0, r1, r2				/* R0=Address of R8 storage */
 	ldmia	r0!, {r2-r6}			/* Recover R8-R11 and R14 (5 registers)*/
 	mov		r8, r2					/* Move to position in high registers */
 	mov		r9, r3
@@ -199,21 +199,20 @@ exception_common:
 	mov		r11, r5
 	mov		r14, r6					/* EXEC_RETURN */
 
-	/* Recover SP (R2), BASEPRI (R3), and R4-R7.  The size of the sofware saved
-	 * portion is 11 words.  5 were recovered above; 6 are recovered by the
-	 * ldmia below.  So adding (4*5) to r1 accounts for all of the software
-	 * saved registers.
+	/* Recover SP (R2), BASEPRI (R3), and R4-R7. Determine the value of
+	 * the stack pointer as it was on entry to the exception handler.
 	 */
 
 	ldmia	r1!, {r2-r7}			/* Recover R4-R7 + 2 temp values */
-	add		r1, #(4*5)				/* R1=Value of MSP/PSP on exception entry */
+	mov		r1, #HW_XCPT_SIZE		/* R1=Size of hardware-saved portion of the context array */
+	sub		r1, r2, r1				/* R1=Value of MSP/PSP on exception entry */
 
 	/* Restore the stack pointer.  The EXC_RETURN value tells us whether the
 	 * context is on the MSP or PSP.
 	 */
 
 	mov		r0, r14					/* Copy high register to low register */
-	lsl		r1, r0, #(31 - EXC_RETURN_PROCESS_BITNO)	/* Move to bit 31 */
+	lsl		r0, #(31 - EXC_RETURN_PROCESS_BITNO)	/* Move to bit 31 */
 	bmi		5f						/* Test bit 31 */
 	msr		msp, r1					/* R1=The main stack pointer */
 	b		6f
diff --git a/nuttx/arch/arm/src/armv6-m/up_initialstate.c b/nuttx/arch/arm/src/armv6-m/up_initialstate.c
index 8e5c37e40..ccb924ebe 100644
--- a/nuttx/arch/arm/src/armv6-m/up_initialstate.c
+++ b/nuttx/arch/arm/src/armv6-m/up_initialstate.c
@@ -115,10 +115,10 @@ void up_initial_state(struct tcb_s *tcb)
       xcp->regs[REG_PIC] = (uint32_t)tcb->dspace->region;
     }
 
-  /* Make certain that bit 0 is set in the main entry address.  This
-   * is only an issue when NXFLAT is enabled.  NXFLAT doesn't know
-   * anything about thumb; the addresses that NXFLAT sets are based
-   * on file header info and won't have bit 0 set.
+  /* Make certain that bit 0 is set in the main entry address.  This is
+   * only an issue when NXFLAT is enabled.  NXFLAT doesn't know anything
+   * about thumb; the addresses that NXFLAT sets are based on file header
+   * info and won't have bit 0 set.
    */
 
 #ifdef CONFIG_NXFLAT
@@ -128,22 +128,24 @@ void up_initial_state(struct tcb_s *tcb)
 
   /* Set privileged- or unprivileged-mode, depending on how NuttX is
    * configured and what kind of thread is being started.
-   *
-   * If the kernel build is not selected, then all threads run in
-   * privileged thread mode.
    */
 
-  xcp->regs[REG_EXC_RETURN] = EXC_RETURN_BASE | EXC_RETURN_THREAD_MODE;
-  xcp->regs[REG_EXC_RETURN] |= EXC_RETURN_STD_CONTEXT;
-
 #ifdef CONFIG_NUTTX_KERNEL
   if ((tcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_KERNEL)
     {
       /* It is a normal task or a pthread.  Set user mode */
 
-      xcp->regs[REG_EXC_RETURN] = EXC_RETURN_PROCESS_STACK;
+      xcp->regs[REG_EXC_RETURN] = EXC_RETURN_UNPRIVTHR;
     }
+  else
 #endif /* CONFIG_NUTTX_KERNEL */
+    {
+      /* If the kernel build is not selected -OR- if this is a kernel
+       * thread, then start it in privileged thread mode.
+       */
+
+      xcp->regs[REG_EXC_RETURN] = EXC_RETURN_PRIVTHR;
+    }
 
   /* Enable or disable interrupts, based on user configuration */
 
diff --git a/nuttx/arch/arm/src/armv7-m/up_initialstate.c b/nuttx/arch/arm/src/armv7-m/up_initialstate.c
index ee523a016..6f9abcd31 100644
--- a/nuttx/arch/arm/src/armv7-m/up_initialstate.c
+++ b/nuttx/arch/arm/src/armv7-m/up_initialstate.c
@@ -155,7 +155,7 @@ void up_initial_state(struct tcb_s *tcb)
     {
       /* It is a normal task or a pthread.  Set user mode */
 
-      xcp->regs[REG_EXC_RETURN] = EXC_RETURN_PROCESS_STACK;
+      xcp->regs[REG_EXC_RETURN] |= EXC_RETURN_PROCESS_STACK;
     }
 #endif /* CONFIG_NUTTX_KERNEL */
 
diff --git a/nuttx/arch/arm/src/nuc1xx/nuc_lowputc.c b/nuttx/arch/arm/src/nuc1xx/nuc_lowputc.c
index ec0c192d2..0855594fe 100644
--- a/nuttx/arch/arm/src/nuc1xx/nuc_lowputc.c
+++ b/nuttx/arch/arm/src/nuc1xx/nuc_lowputc.c
@@ -63,18 +63,21 @@
 #ifdef HAVE_SERIAL_CONSOLE
 #  if defined(CONFIG_UART0_SERIAL_CONSOLE)
 #    define NUC_CONSOLE_BASE     NUC_UART0_BASE
+#    define NUC_CONSOLE_DEPTH    UART0_FIFO_DEPTH
 #    define NUC_CONSOLE_BAUD     CONFIG_UART0_BAUD
 #    define NUC_CONSOLE_BITS     CONFIG_UART0_BITS
 #    define NUC_CONSOLE_PARITY   CONFIG_UART0_PARITY
 #    define NUC_CONSOLE_2STOP    CONFIG_UART0_2STOP
 #  elif defined(CONFIG_UART1_SERIAL_CONSOLE)
 #    define NUC_CONSOLE_BASE     NUC_UART1_BASE
+#    define NUC_CONSOLE_DEPTH    UART1_FIFO_DEPTH
 #    define NUC_CONSOLE_BAUD     CONFIG_UART1_BAUD
 #    define NUC_CONSOLE_BITS     CONFIG_UART1_BITS
 #    define NUC_CONSOLE_PARITY   CONFIG_UART1_PARITY
 #    define NUC_CONSOLE_2STOP    CONFIG_UART1_2STOP
 #  elif defined(CONFIG_UART2_SERIAL_CONSOLE)
 #    define NUC_CONSOLE_BASE     NUC_UART2_BASE
+#    define NUC_CONSOLE_DEPTH    UART2_FIFO_DEPTH
 #    define NUC_CONSOLE_BAUD     CONFIG_UART2_BAUD
 #    define NUC_CONSOLE_BITS     CONFIG_UART2_BITS
 #    define NUC_CONSOLE_PARITY   CONFIG_UART2_PARITY
@@ -97,6 +100,38 @@
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
+
+/****************************************************************************
+ * Name: nuc_console_ready
+ *
+ * Description:
+ *   Wait until the console is ready to add another character to the TX
+ *   FIFO.
+ *
+ *****************************************************************************/
+
+#ifdef HAVE_SERIAL_CONSOLE
+static inline void nuc_console_ready(void)
+{
+#if 1
+  /* Wait for the TX FIFO to be empty (excessive!) */
+
+  while ((getreg32(NUC_CONSOLE_BASE + NUC_UART_FSR_OFFSET) & UART_FSR_TX_EMPTY) == 0);
+#else
+  uint32_t depth;
+
+  /* Wait until there is space in the TX FIFO */
+
+  do
+    {
+      register uint32_t regval = getreg32(NUC_CONSOLE_BASE + NUC_UART_FSR_OFFSET);
+      depth  = (regval & UART_FSR_TX_POINTER_MASK) >> UART_FSR_TX_POINTER_SHIFT;
+    }
+  while (depth >= (NUC_CONSOLE_DEPTH-1));
+#endif
+}
+#endif /* HAVE_SERIAL_CONSOLE */
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -293,9 +328,9 @@ void nuc_lowsetup(void)
 void nuc_lowputc(uint32_t ch)
 {
 #ifdef HAVE_SERIAL_CONSOLE
-  /* Wait for the TX FIFO to be empty (excessive!) */
+  /* Wait for the TX FIFO to become available */
 
-  while ((getreg32(NUC_CONSOLE_BASE + NUC_UART_FSR_OFFSET) & UART_FSR_TX_EMPTY) == 0);
+  nuc_console_ready();
 
   /* Then write the character to to the TX FIFO */
 
diff --git a/nuttx/arch/arm/src/nuc1xx/nuc_serial.c b/nuttx/arch/arm/src/nuc1xx/nuc_serial.c
index 060d274ef..6f095826c 100644
--- a/nuttx/arch/arm/src/nuc1xx/nuc_serial.c
+++ b/nuttx/arch/arm/src/nuc1xx/nuc_serial.c
@@ -159,7 +159,7 @@ static struct nuc_dev_s g_uart0priv =
   .irq            = NUC_IRQ_UART0,
   .parity         = CONFIG_UART0_PARITY,
   .bits           = CONFIG_UART0_BITS,
-  .depth          = UART0_FIFO_DEPTH,
+  .depth          = (UART0_FIFO_DEPTH-1),
   .stopbits2      = CONFIG_UART0_2STOP,
 };
 
@@ -190,7 +190,7 @@ static struct nuc_dev_s g_uart1priv =
   .irq            = NUC_IRQ_UART1,
   .parity         = CONFIG_UART1_PARITY,
   .bits           = CONFIG_UART1_BITS,
-  .depth          = UART1_FIFO_DEPTH,
+  .depth          = (UART1_FIFO_DEPTH-1),
   .stopbits2      = CONFIG_UART1_2STOP,
 };
 
@@ -221,7 +221,7 @@ static struct nuc_dev_s g_uart2priv =
   .irq            = NUC_IRQ_UART2,
   .parity         = CONFIG_UART2_PARITY,
   .bits           = CONFIG_UART2_BITS,
-  .depth          = UART2_FIFO_DEPTH,
+  .depth          = (UART2_FIFO_DEPTH-1),
   .stopbits2      = CONFIG_UART2_2STOP,
 };
 
diff --git a/nuttx/sched/os_bringup.c b/nuttx/sched/os_bringup.c
index 85cb5e627..acf367c97 100644
--- a/nuttx/sched/os_bringup.c
+++ b/nuttx/sched/os_bringup.c
@@ -142,7 +142,7 @@ int os_bringup(void)
   g_pgworker = KERNEL_THREAD("pgfill", CONFIG_PAGING_DEFPRIO,
                              CONFIG_PAGING_STACKSIZE,
                              (main_t)pg_worker, (FAR char * const *)NULL);
-  ASSERT(g_pgworker != ERROR);
+  ASSERT(g_pgworker > 0);
 #endif
 
   /* Start the worker thread that will serve as the device driver "bottom-
@@ -155,7 +155,7 @@ int os_bringup(void)
   g_work[HPWORK].pid = KERNEL_THREAD("work0", CONFIG_SCHED_WORKPRIORITY,
                                      CONFIG_SCHED_WORKSTACKSIZE,
                                      (main_t)work_hpthread, (FAR char * const *)NULL);
-  ASSERT(g_work[HPWORK].pid != ERROR);
+  ASSERT(g_work[HPWORK].pid > 0);
 
   /* Start a lower priority worker thread for other, non-critical continuation
    * tasks
@@ -167,7 +167,7 @@ int os_bringup(void)
   g_work[LPWORK].pid = KERNEL_THREAD("work1", CONFIG_SCHED_LPWORKPRIORITY,
                                      CONFIG_SCHED_LPWORKSTACKSIZE,
                                      (main_t)work_lpthread, (FAR char * const *)NULL);
-  ASSERT(g_work[LPWORK].pid != ERROR);
+  ASSERT(g_work[LPWORK].pid > 0);
 #endif
 #endif
 
@@ -183,7 +183,7 @@ int os_bringup(void)
   init_taskid = TASK_CREATE("init", SCHED_PRIORITY_DEFAULT,
                             CONFIG_USERMAIN_STACKSIZE,
                             (main_t)CONFIG_USER_ENTRYPOINT, (FAR char * const *)NULL);
-  ASSERT(init_taskid != ERROR);
+  ASSERT(init_taskid > 0);
 
   /* We an save a few bytes by discarding the IDLE thread's environment. */