[Xen-devel] [RFC PATCH v1] xen/arm: split the init_xen_time() in 2 parts

[Oleksandr Tyshchenko <oleksandr.tyshchenko@xxxxxxxxxxxxxxx>]

Create preinit_xen_time() and move to it minimum required
subset of operations needed to properly initialized
cpu_khz and boot_count vars. This is allow us to use udelay()
immediately after the call.

Signed-off-by: Oleksandr Tyshchenko <oleksandr.tyshchenko@xxxxxxxxxxxxxxx>
CC: Julien Grall <julien.grall@xxxxxxxxxx>
---
 xen/arch/arm/setup.c   |  2 ++
 xen/arch/arm/time.c    | 71 ++++++++++++++++++++++++++++++++------------------
 xen/include/xen/time.h |  1 +
 3 files changed, 48 insertions(+), 26 deletions(-)

diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index f49569d..dbd7d5a 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -743,6 +743,8 @@ void __init start_xen(unsigned long boot_phys_offset,
 
     init_IRQ();
 
+    preinit_xen_time();
+
     dt_uart_init();
     console_init_preirq();
     console_init_ring();
diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
index 455f217..b2560db 100644
--- a/xen/arch/arm/time.c
+++ b/xen/arch/arm/time.c
@@ -61,25 +61,56 @@ unsigned int timer_get_irq(enum timer_ppi ppi)
     return muldiv64(ns, 1000 * cpu_khz, SECONDS(1));
 }
 
-/* Set up the timer on the boot CPU */
-int __init init_xen_time(void)
+static __init struct dt_device_node *find_timer_node(void)
+{
+       static const struct dt_device_match timer_ids[] __initconst =
+       {
+           DT_MATCH_TIMER,
+           { /* sentinel */ },
+       };
+
+       return dt_find_matching_node(NULL, timer_ids);
+}
+
+/* Set up the timer on the boot CPU (early init function) */
+int __init preinit_xen_time(void)
 {
-    static const struct dt_device_match timer_ids[] __initconst =
-    {
-        DT_MATCH_TIMER,
-        { /* sentinel */ },
-    };
     struct dt_device_node *dev;
     int res;
-    unsigned int i;
     u32 rate;
 
-    dev = dt_find_matching_node(NULL, timer_ids);
+    dev = find_timer_node();
     if ( !dev )
         panic("Unable to find a compatible timer in the device tree");
 
     dt_device_set_used_by(dev, DOMID_XEN);
 
+    res = platform_init_time();
+    if ( res )
+        panic("Timer: Cannot initialize platform timer");
+
+    res = dt_property_read_u32(dev, "clock-frequency", &rate);
+    if ( res )
+        cpu_khz = rate / 1000;
+    else
+        cpu_khz = READ_SYSREG32(CNTFRQ_EL0) / 1000;
+
+    boot_count = READ_SYSREG64(CNTPCT_EL0);
+
+    return 0;
+}
+
+/* Set up the timer on the boot CPU (late init function) */
+int __init init_xen_time(void)
+{
+    struct dt_device_node *dev;
+    int res;
+    unsigned int i;
+
+    dev = find_timer_node();
+    if ( !dev )
+        panic("Unable to find a compatible timer in the device tree");
+
     /* Retrieve all IRQs for the timer */
     for ( i = TIMER_PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++ )
     {
@@ -90,27 +121,15 @@ int __init init_xen_time(void)
         timer_irq[i] = res;
     }
 
-    printk("Generic Timer IRQ: phys=%u hyp=%u virt=%u\n",
-           timer_irq[TIMER_PHYS_NONSECURE_PPI],
-           timer_irq[TIMER_HYP_PPI],
-           timer_irq[TIMER_VIRT_PPI]);
-
-    res = platform_init_time();
-    if ( res )
-        panic("Timer: Cannot initialize platform timer");
-
     /* Check that this CPU supports the Generic Timer interface */
     if ( !cpu_has_gentimer )
         panic("CPU does not support the Generic Timer v1 interface");
 
-    res = dt_property_read_u32(dev, "clock-frequency", &rate);
-    if ( res )
-        cpu_khz = rate / 1000;
-    else
-        cpu_khz = READ_SYSREG32(CNTFRQ_EL0) / 1000;
-
-    boot_count = READ_SYSREG64(CNTPCT_EL0);
-    printk("Using generic timer at %lu KHz\n", cpu_khz);
+    printk("Generic Timer IRQ: phys=%u hyp=%u virt=%u Freq: %lu KHz\n",
+           timer_irq[TIMER_PHYS_NONSECURE_PPI],
+           timer_irq[TIMER_HYP_PPI],
+           timer_irq[TIMER_VIRT_PPI],
+           cpu_khz);
 
     return 0;
 }
diff --git a/xen/include/xen/time.h b/xen/include/xen/time.h
index 709501f..fc49f71 100644
--- a/xen/include/xen/time.h
+++ b/xen/include/xen/time.h
@@ -12,6 +12,7 @@
 #include <public/xen.h>
 
 extern int init_xen_time(void);
+extern int preinit_xen_time(void);
 extern void cstate_restore_tsc(void);
 
 extern unsigned long cpu_khz;
-- 
1.9.1


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