[Xen-devel] [PATCH] xen/arm: Some clean up in time.c

[Julien Grall <julien.grall@xxxxxxxxxx>]

The file xen/arm/time.c contains some unused code:
    - calibrate_timer: firmware already set correctly CNTFRQ. If it's
    not the case the device tree will containt a property clock-frequency
    in the timer node
    - USE_HYP_TIMER: It's set unconditionally to 1. I didn't see any
    recent model having issue with the hyp timer. I think we can drop
    it safely.

Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
---
 xen/arch/arm/time.c |   52 ---------------------------------------------------
 1 file changed, 52 deletions(-)

diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
index 4c3e1a6..a6436f1 100644
--- a/xen/arch/arm/time.c
+++ b/xen/arch/arm/time.c
@@ -36,13 +36,6 @@
 #include <asm/cpufeature.h>
 #include <asm/platform.h>
 
-/*
- * Unfortunately the hypervisor timer interrupt appears to be buggy in
- * some versions of the model. Disable this to use the physical timer
- * instead.
- */
-#define USE_HYP_TIMER 1
-
 uint64_t __read_mostly boot_count;
 
 /* For fine-grained timekeeping, we use the ARM "Generic Timer", a
@@ -68,37 +61,6 @@ unsigned int timer_get_irq(enum timer_ppi ppi)
     return muldiv64(ns, 1000 * cpu_khz, SECONDS(1));
 }
 
-/* TODO: On a real system the firmware would have set the frequency in
-   the CNTFRQ register.  Also we'd need to use devicetree to find
-   the RTC.  When we've seen some real systems, we can delete this.
-static uint32_t calibrate_timer(void)
-{
-    uint32_t sec;
-    uint64_t start, end;
-    paddr_t rtc_base = 0x1C170000ull;
-    volatile uint32_t *rtc;
-
-    ASSERT(!local_irq_is_enabled());
-    set_fixmap(FIXMAP_MISC, rtc_base >> PAGE_SHIFT, DEV_SHARED);
-    rtc = (uint32_t *) FIXMAP_ADDR(FIXMAP_MISC);
-
-    printk("Calibrating timer against RTC...");
-    // Turn on the RTC
-    rtc[3] = 1;
-    // Wait for an edge
-    sec = rtc[0] + 1;
-    do {} while ( rtc[0] != sec );
-    // Now time a few seconds
-    start = READ_SYSREG64(CNTPCT_EL0);
-    do {} while ( rtc[0] < sec + 32 );
-    end = READ_SYSREG64(CNTPCT_EL0);
-    printk("done.\n");
-
-    clear_fixmap(FIXMAP_MISC);
-    return (end - start) / 32;
-}
-*/
-
 /* Set up the timer on the boot CPU */
 int __init init_xen_time(void)
 {
@@ -169,22 +131,13 @@ int reprogram_timer(s_time_t timeout)
 
     if ( timeout == 0 )
     {
-#if USE_HYP_TIMER
         WRITE_SYSREG32(0, CNTHP_CTL_EL2);
-#else
-        WRITE_SYSREG32(0, CNTP_CTL_EL0);
-#endif
         return 1;
     }
 
     deadline = ns_to_ticks(timeout) + boot_count;
-#if USE_HYP_TIMER
     WRITE_SYSREG64(deadline, CNTHP_CVAL_EL2);
     WRITE_SYSREG32(CNTx_CTL_ENABLE, CNTHP_CTL_EL2);
-#else
-    WRITE_SYSREG64(deadline, CNTP_CVAL_EL0);
-    WRITE_SYSREG32(CNTx_CTL_ENABLE, CNTP_CTL_EL0);
-#endif
     isb();
 
     /* No need to check for timers in the past; the Generic Timer fires
@@ -226,13 +179,8 @@ void __cpuinit init_timer_interrupt(void)
 {
     /* Sensible defaults */
     WRITE_SYSREG64(0, CNTVOFF_EL2);     /* No VM-specific offset */
-#if USE_HYP_TIMER
     /* Do not let the VMs program the physical timer, only read the physical 
counter */
     WRITE_SYSREG32(CNTHCTL_PA, CNTHCTL_EL2);
-#else
-    /* Cannot let VMs access physical counter if we are using it */
-    WRITE_SYSREG32(0, CNTHCTL_EL2);
-#endif
     WRITE_SYSREG32(0, CNTP_CTL_EL0);    /* Physical timer disabled */
     WRITE_SYSREG32(0, CNTHP_CTL_EL2);   /* Hypervisor's timer disabled */
     isb();
-- 
1.7.10.4


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel