[kvm-unit-tests PATCH V3 4/5] lib/powerpc: Implement generic sleep function for use in unit tests

From: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
To: kvm@vger.kernel.org
Cc: sjitindarsingh@gmail.com, pbonzini@redhat.com,
	rkrcmar@redhat.com, kvm-ppc@vger.kernel.org, lvivier@redhat.com,
	thuth@redhat.com, drjones@redhat.com
Subject: [kvm-unit-tests PATCH V3 4/5] lib/powerpc: Implement generic sleep function for use in unit tests
Date: Tue, 16 Aug 2016 17:18:14 +1000	[thread overview]
Message-ID: <1471331895-29887-4-git-send-email-sjitindarsingh@gmail.com> (raw)
In-Reply-To: <1471331895-29887-1-git-send-email-sjitindarsingh@gmail.com>

It would be nice if we had a generic sleep function which could be used
in unit tests, add one.

Add the variable tb_hz used to store the time base frequency which is read
from the device tree on setup.

Add functions msleep, usleep and sleep in processor.c to sleep for a given
number of milliseconds, microseconds and time base ticks respectively.

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
---

Change Log:

V2 -> V3:
	- Add patch to series

Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
---
 lib/powerpc/asm/processor.h | 19 +++++++++++++++++++
 lib/powerpc/asm/setup.h     |  2 ++
 lib/powerpc/processor.c     | 13 +++++++++++++
 lib/powerpc/setup.c         | 12 ++++++++++++
 4 files changed, 46 insertions(+)

diff --git a/lib/powerpc/asm/processor.h b/lib/powerpc/asm/processor.h
index 09692bd..9554e08 100644
--- a/lib/powerpc/asm/processor.h
+++ b/lib/powerpc/asm/processor.h
@@ -1,11 +1,30 @@
 #ifndef _ASMPOWERPC_PROCESSOR_H_
 #define _ASMPOWERPC_PROCESSOR_H_
 
+#include <libcflat.h>
 #include <asm/ptrace.h>
 
+#define cpu_relax() asm volatile ("" : : : "memory")
+
 #ifndef __ASSEMBLY__
 void handle_exception(int trap, void (*func)(struct pt_regs *, void *), void *);
 void do_handle_exception(struct pt_regs *regs);
 #endif /* __ASSEMBLY__ */
 
+static inline uint64_t get_tb(void)
+{
+	uint64_t tb;
+	asm volatile ("mfspr %[tb],268" : [tb] "=r" (tb));
+	return tb;
+}
+
+extern void delay(uint64_t cycles);
+extern void udelay(uint64_t us);
+
+static inline void mdelay(uint64_t ms)
+{
+	while (ms--)
+		udelay(1000);
+}
+
 #endif /* _ASMPOWERPC_PROCESSOR_H_ */
diff --git a/lib/powerpc/asm/setup.h b/lib/powerpc/asm/setup.h
index b1e1e5a..23b4156 100644
--- a/lib/powerpc/asm/setup.h
+++ b/lib/powerpc/asm/setup.h
@@ -11,6 +11,8 @@
 extern u32 cpus[NR_CPUS];
 extern int nr_cpus;
 
+extern uint64_t tb_hz;
+
 #define NR_MEM_REGIONS		8
 #define MR_F_PRIMARY		(1U << 0)
 struct mem_region {
diff --git a/lib/powerpc/processor.c b/lib/powerpc/processor.c
index a78bc3c..c84bae5 100644
--- a/lib/powerpc/processor.c
+++ b/lib/powerpc/processor.c
@@ -5,6 +5,7 @@
 #include <libcflat.h>
 #include <asm/processor.h>
 #include <asm/ptrace.h>
+#include <asm/setup.h>
 
 static struct {
 	void (*func)(struct pt_regs *, void *data);
@@ -36,3 +37,15 @@ void do_handle_exception(struct pt_regs *regs)
 	printf("unhandled cpu exception 0x%lx\n", regs->trap);
 	abort();
 }
+
+void delay(uint64_t cycles)
+{
+	uint64_t start = get_tb();
+	while((get_tb() - start) < cycles)
+		cpu_relax();
+}
+
+void udelay(uint64_t us)
+{
+	delay((us * tb_hz) / 1000000);
+}
diff --git a/lib/powerpc/setup.c b/lib/powerpc/setup.c
index e3d2afa..e7fa525 100644
--- a/lib/powerpc/setup.c
+++ b/lib/powerpc/setup.c
@@ -24,6 +24,7 @@ extern void setup_args_progname(const char *args);
 
 u32 cpus[NR_CPUS] = { [0 ... NR_CPUS-1] = (~0U) };
 int nr_cpus;
+uint64_t tb_hz;
 
 struct mem_region mem_regions[NR_MEM_REGIONS];
 phys_addr_t __physical_start, __physical_end;
@@ -51,6 +52,17 @@ static void cpu_set(int fdtnode, u32 regval, void *info)
 	}
 	cpus[cpu] = regval;
 
+	/* set timebase frequency */
+	if (!tb_hz) {
+		const struct fdt_property *prop;
+		u32 *data;
+		prop = fdt_get_property(dt_fdt(), fdtnode,
+					"timebase-frequency", NULL);
+		assert(prop != NULL);
+		data = (u32 *)prop->data;
+		tb_hz = fdt32_to_cpu(*data);
+	}
+
 	/* set exception stack address for this CPU (in SPGR0) */
 
 	asm volatile ("mtsprg0 %[addr]" ::
-- 
2.5.5

