linux-kernel - [PATCH v2 3/5] HID: intel_ish-hid: convert timespec to ktime

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Message-Id: <20170518202144.3482304-4-arnd@arndb.de>
Date:   Thu, 18 May 2017 22:21:42 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Jiri Kosina <jikos@...nel.org>
Cc:     linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        arnd@...db.de
Subject: [PATCH v2 3/5] HID: intel_ish-hid: convert timespec to ktime_t

The internal accounting uses 'timespec' based time stamps, which is
slightly inefficient and also problematic once we get to the time_t
overflow in 2038.

When communicating to the firmware, we even get an open-coded 64-bit
division that prevents the code from being build-tested on 32-bit
architectures and is inefficient due to the double conversion from
64-bit nanoseconds to seconds+nanoseconds and then microseconds.

This changes the code to use ktime_t instead.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/hid/intel-ish-hid/ipc/ipc.c      | 15 ++++-----------
 drivers/hid/intel-ish-hid/ishtp/client.c |  4 ++--
 drivers/hid/intel-ish-hid/ishtp/client.h |  6 +++---
 drivers/hid/intel-ish-hid/ishtp/hbm.c    | 11 ++++-------
 4 files changed, 13 insertions(+), 23 deletions(-)

diff --git a/drivers/hid/intel-ish-hid/ipc/ipc.c b/drivers/hid/intel-ish-hid/ipc/ipc.c
index 842d8416a7a6..9a60ec13cb10 100644
--- a/drivers/hid/intel-ish-hid/ipc/ipc.c
+++ b/drivers/hid/intel-ish-hid/ipc/ipc.c
@@ -296,17 +296,12 @@ static int write_ipc_from_queue(struct ishtp_device *dev)
 	/* If sending MNG_SYNC_FW_CLOCK, update clock again */
 	if (IPC_HEADER_GET_PROTOCOL(doorbell_val) == IPC_PROTOCOL_MNG &&
 		IPC_HEADER_GET_MNG_CMD(doorbell_val) == MNG_SYNC_FW_CLOCK) {
-		struct timespec ts_system;
-		struct timeval tv_utc;
-		uint64_t        usec_system, usec_utc;
+		uint64_t usec_system, usec_utc;
 		struct ipc_time_update_msg time_update;
 		struct time_sync_format ts_format;
 
-		get_monotonic_boottime(&ts_system);
-		do_gettimeofday(&tv_utc);
-		usec_system = (timespec_to_ns(&ts_system)) / NSEC_PER_USEC;
-		usec_utc = (uint64_t)tv_utc.tv_sec * 1000000 +
-						((uint32_t)tv_utc.tv_usec);
+		usec_system = ktime_to_us(ktime_get_boottime());
+		usec_utc = ktime_to_us(ktime_get_real());
 		ts_format.ts1_source = HOST_SYSTEM_TIME_USEC;
 		ts_format.ts2_source = HOST_UTC_TIME_USEC;
 		ts_format.reserved = 0;
@@ -575,15 +570,13 @@ static void fw_reset_work_fn(struct work_struct *unused)
 static void _ish_sync_fw_clock(struct ishtp_device *dev)
 {
 	static unsigned long	prev_sync;
-	struct timespec	ts;
 	uint64_t	usec;
 
 	if (prev_sync && jiffies - prev_sync < 20 * HZ)
 		return;
 
 	prev_sync = jiffies;
-	get_monotonic_boottime(&ts);
-	usec = (timespec_to_ns(&ts)) / NSEC_PER_USEC;
+	usec = ktime_to_us(ktime_get_boottime());
 	ipc_send_mng_msg(dev, MNG_SYNC_FW_CLOCK, &usec, sizeof(uint64_t));
 }
 
diff --git a/drivers/hid/intel-ish-hid/ishtp/client.c b/drivers/hid/intel-ish-hid/ishtp/client.c
index f54689ee67e1..007443ef5fca 100644
--- a/drivers/hid/intel-ish-hid/ishtp/client.c
+++ b/drivers/hid/intel-ish-hid/ishtp/client.c
@@ -921,7 +921,7 @@ void recv_ishtp_cl_msg(struct ishtp_device *dev,
 
 	if (complete_rb) {
 		cl = complete_rb->cl;
-		getnstimeofday(&cl->ts_rx);
+		cl->ts_rx = ktime_get();
 		++cl->recv_msg_cnt_ipc;
 		ishtp_cl_read_complete(complete_rb);
 	}
@@ -1038,7 +1038,7 @@ void recv_ishtp_cl_msg_dma(struct ishtp_device *dev, void *msg,
 
 	if (complete_rb) {
 		cl = complete_rb->cl;
-		getnstimeofday(&cl->ts_rx);
+		cl->ts_rx = ktime_get();
 		++cl->recv_msg_cnt_dma;
 		ishtp_cl_read_complete(complete_rb);
 	}
diff --git a/drivers/hid/intel-ish-hid/ishtp/client.h b/drivers/hid/intel-ish-hid/ishtp/client.h
index 444d069c2ed4..79eade547f5d 100644
--- a/drivers/hid/intel-ish-hid/ishtp/client.h
+++ b/drivers/hid/intel-ish-hid/ishtp/client.h
@@ -118,9 +118,9 @@ struct ishtp_cl {
 	unsigned int	out_flow_ctrl_cnt;
 
 	/* Rx msg ... out FC timing */
-	struct timespec ts_rx;
-	struct timespec ts_out_fc;
-	struct timespec ts_max_fc_delay;
+	ktime_t ts_rx;
+	ktime_t ts_out_fc;
+	ktime_t ts_max_fc_delay;
 	void *client_data;
 };
 
diff --git a/drivers/hid/intel-ish-hid/ishtp/hbm.c b/drivers/hid/intel-ish-hid/ishtp/hbm.c
index b7213608ce43..ae4a69f7f2f4 100644
--- a/drivers/hid/intel-ish-hid/ishtp/hbm.c
+++ b/drivers/hid/intel-ish-hid/ishtp/hbm.c
@@ -321,13 +321,10 @@ int ishtp_hbm_cl_flow_control_req(struct ishtp_device *dev,
 	if (!rv) {
 		++cl->out_flow_ctrl_creds;
 		++cl->out_flow_ctrl_cnt;
-		getnstimeofday(&cl->ts_out_fc);
-		if (cl->ts_rx.tv_sec && cl->ts_rx.tv_nsec) {
-			struct timespec ts_diff;
-
-			ts_diff = timespec_sub(cl->ts_out_fc, cl->ts_rx);
-			if (timespec_compare(&ts_diff, &cl->ts_max_fc_delay)
-					> 0)
+		cl->ts_out_fc = ktime_get();
+		if (cl->ts_rx) {
+			ktime_t ts_diff = ktime_sub(cl->ts_out_fc, cl->ts_rx);
+			if (ktime_after(ts_diff, cl->ts_max_fc_delay))
 				cl->ts_max_fc_delay = ts_diff;
 		}
 	} else {
-- 
2.9.0