[Minios-devel] [UNIKRAFT PATCH v5 4/7] plat/common: Share arch_timer fdt node among functions

[Jia He <justin.he@xxxxxxx>]

Several function will use the arch_timer fdt node to get information
from device tree. We find it once, and share it among functions. this
will avoid find arch_timer fdt everywhere.

Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
Signed-off-by: Jianyong Wu <jianyong.wu@xxxxxxx>
Signed-off-by: Jia He <justin.he@xxxxxxx>
---
 plat/common/arm/time.c | 59 +++++++++++++++++++++---------------------
 1 file changed, 29 insertions(+), 30 deletions(-)

diff --git a/plat/common/arm/time.c b/plat/common/arm/time.c
index 98b3764..97521c5 100644
--- a/plat/common/arm/time.c
+++ b/plat/common/arm/time.c
@@ -33,6 +33,7 @@
  */
 #include <stdlib.h>
 #include <libfdt.h>
+#include <ofw/fdt.h>
 #include <uk/assert.h>
 #include <uk/plat/time.h>
 #include <uk/plat/irq.h>
@@ -44,6 +45,12 @@
  * portable way to handover the DTB entry point to common platform code */
 #include <kvm/config.h>
 
+static const char * const arch_timer_list[] = {
+       "arm,armv8-timer",
+       "arm,armv7-timer",
+       NULL
+};
+
 static uint64_t boot_ticks;
 static uint32_t counter_freq;
 
@@ -132,41 +139,26 @@ static void calculate_mult_shift(uint32_t *mult, uint8_t 
*shift,
        *shift = sft;
 }
 
-/*
- * On a few platforms the frequency is not configured correctly
- * by the firmware. A property in the DT (clock-frequency) has
- * been introduced to workaround those firmware. So, we will try
- * to get clock-frequency from DT first, if failed we will read
- * the register directly.
- */
-static uint32_t get_counter_frequency(void)
+static uint32_t generic_timer_get_frequency(int fdt_timer)
 {
-       int fdt_archtimer, len;
+       int len;
        const uint64_t *fdt_freq;
 
-       /* Try to find arm,armv8-timer first */
-       fdt_archtimer = fdt_node_offset_by_compatible(_libkvmplat_cfg.dtb,
-                                               -1, "arm,armv8-timer");
-       /* If failed, try to find arm,armv7-timer */
-       if (fdt_archtimer < 0)
-               fdt_archtimer = fdt_node_offset_by_compatible(
-                                                       _libkvmplat_cfg.dtb,
-                                                       -1, "arm,armv7-timer");
-       /* DT doesn't provide arch timer information */
-       if (fdt_archtimer < 0)
-               goto endnofreq;
-
+       /*
+        * On a few platforms the frequency is not configured correctly
+        * by the firmware. A property in the DT (clock-frequency) has
+        * been introduced to workaround those firmware.
+        */
        fdt_freq = fdt_getprop(_libkvmplat_cfg.dtb,
-                       fdt_archtimer, "clock-frequency", &len);
+                       fdt_timer, "clock-frequency", &len);
        if (!fdt_freq || (len <= 0)) {
                uk_pr_info("No clock-frequency found, reading from register 
directly.\n");
-               goto endnofreq;
+
+               /* No workaround, get from register directly */
+               return SYSREG_READ32(cntfrq_el0);
        }
 
        return fdt32_to_cpu(fdt_freq[0]);
-
-endnofreq:
-       return SYSREG_READ32(cntfrq_el0);
 }
 
 #ifdef CONFIG_ARM64_ERRATUM_858921
@@ -211,9 +203,10 @@ static uint64_t generic_timer_epochoffset(void)
        return 0;
 }
 
-static int generic_timer_init(void)
+static int generic_timer_init(int fdt_timer)
 {
-       counter_freq = get_counter_frequency();
+       /* Get counter frequency from DTB or register */
+       counter_freq = generic_timer_get_frequency(fdt_timer);
 
        /*
         * Calculate the shift factor and scaling multiplier for
@@ -276,7 +269,7 @@ static int timer_handler(void *arg __unused)
 /* must be called before interrupts are enabled */
 void ukplat_time_init(void)
 {
-       int rc;
+       int rc, fdt_timer;
 
        /*
         * Monotonic time begins at boot_ticks (first read of counter
@@ -284,11 +277,17 @@ void ukplat_time_init(void)
         */
        boot_ticks = generic_timer_get_ticks();
 
+       /* Currently, we only support 1 timer per system */
+       fdt_timer = fdt_node_offset_by_compatible_list(_libkvmplat_cfg.dtb,
+                               -1, arch_timer_list);
+       if (fdt_timer < 0)
+               UK_CRASH("Could not find arch timer!\n");
+
        rc = ukplat_irq_register(0, timer_handler, NULL);
        if (rc < 0)
                UK_CRASH("Failed to register timer interrupt handler\n");
 
-       rc = generic_timer_init();
+       rc = generic_timer_init(fdt_timer);
        if (rc < 0)
                UK_CRASH("Failed to initialize platform time\n");
 }
-- 
2.17.1


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