Changeset f09f059 in mainline for kernel/genarch/src/drivers/am335x/timer.c

Timestamp:

2013-02-13T22:10:05Z (11 years ago)

Author:

Maurizio Lombardi <m.lombardi85@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

ddb3051

Parents:

4a09b86

Message:

write the timer registers in posted mode

File:

• kernel/genarch/src/drivers/am335x/timer.c (modified) (6 diffs)

kernel/genarch/src/drivers/am335x/timer.c

@@ -38 +38 @@
 #include <errno.h>
 
+typedef enum {
+        REG_TCLR = 0x00,
+        REG_TCRR = 0x01,
+        REG_TLDR = 0x02,
+        REG_TTGR = 0x04
+} timer_reg_t;
 
 typedef struct timer_regs_mmap {
@@ -54 +60 @@
         { .base = AM335x_DMTIMER7_BASE_ADDRESS, .size = AM335x_DMTIMER7_SIZE },
 };
+
+static void
+write_register_posted(am335x_timer_t *timer, timer_reg_t reg, uint32_t value)
+{
+        am335x_timer_regs_t *regs = timer->regs;
+
+        while (regs->twps & reg);
+
+        switch (reg) {
+        default:
+                return;
+        case REG_TCLR:
+                regs->tclr = value;
+                break;
+        case REG_TCRR:
+                regs->tcrr = value;
+                break;
+        case REG_TLDR:
+                regs->tldr = value;
+                break;
+        }
+}
 
 void
@@ -75 +103 @@
         am335x_timer_regs_t *regs = timer->regs;
 
+        /* Enable the posted mode of operation */
+        regs->tsicr |= AM335x_TIMER_TSICR_POSTED_FLAG;
+
         /* Stop the timer */
         am335x_timer_stop(timer);
@@ -81 +112 @@
         am335x_timer_reset(timer);
 
+        unsigned tclr = regs->tclr;
+
+        /* Disable compare mode */
+        tclr &= ~AM335x_TIMER_TCLR_CE_FLAG;
         /* Disable the prescaler */
-        regs->tclr &= ~AM335x_TIMER_TCLR_PRE_FLAG;
+        tclr &= ~AM335x_TIMER_TCLR_PRE_FLAG;
+        /* Enable auto-reload mode */
+        tclr |= AM335x_TIMER_TCLR_AR_FLAG;
 
-        /* Enable auto-reload mode */
-        regs->tclr |= AM335x_TIMER_TCLR_AR_FLAG;
+        write_register_posted(timer, REG_TCLR, tclr);
 
         /* Disable the emulation mode */
         regs->tiocp_cfg |= AM335x_TIMER_TIOCPCFG_EMUFREE_FLAG;
 
-        unsigned const count = 0xFFFFFFFE - (srcclk_hz / hz);
-        regs->tcrr = count;
-        regs->tldr = count;
+        unsigned const count = 0xFFFFFFFF - (srcclk_hz / hz + 1);
+        write_register_posted(timer, REG_TCRR, count);
+        write_register_posted(timer, REG_TLDR, count);
 }
 
@@ -116 +152 @@
         /* Disable the interrupt */
         timer->regs->irqenable_clr |= AM335x_TIMER_IRQENABLE_CLR_OVF_FLAG;
+        timer->regs->irqwakeen &= ~AM335x_TIMER_IRQWAKEEN_OVF_FLAG;
         /* Stop the timer */
-        timer->regs->tclr &= ~AM335x_TIMER_TCLR_ST_FLAG;
+        write_register_posted(timer, REG_TCLR,
+            timer->regs->tclr & ~AM335x_TIMER_TCLR_ST_FLAG);
 }
 
@@ -125 +163 @@
         /* Enable the interrupt */
         timer->regs->irqenable_set |= AM335x_TIMER_IRQENABLE_SET_OVF_FLAG;
+        timer->regs->irqwakeen |= AM335x_TIMER_IRQWAKEEN_OVF_FLAG;
         /* Start the clock */
-        timer->regs->tclr |= AM335x_TIMER_TCLR_ST_FLAG;
+        write_register_posted(timer, REG_TCLR,
+            timer->regs->tclr | AM335x_TIMER_TCLR_ST_FLAG);
 }