netdev - [PATCH net 3/4] ice: dpll: fix phase offset value

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Date: Wed, 27 Dec 2023 10:25:32 -0800
From: Tony Nguyen <anthony.l.nguyen@...el.com>
To: davem@...emloft.net,
	kuba@...nel.org,
	pabeni@...hat.com,
	edumazet@...gle.com,
	netdev@...r.kernel.org
Cc: Arkadiusz Kubalewski <arkadiusz.kubalewski@...el.com>,
	anthony.l.nguyen@...el.com,
	vadim.fedorenko@...ux.dev,
	jiri@...nulli.us,
	Aleksandr Loktionov <aleksandr.loktionov@...el.com>,
	Przemek Kitszel <przemyslaw.kitszel@...el.com>,
	Paul Menzel <pmenzel@...gen.mpg.de>,
	Pucha Himasekhar Reddy <himasekharx.reddy.pucha@...el.com>
Subject: [PATCH net 3/4] ice: dpll: fix phase offset value

From: Arkadiusz Kubalewski <arkadiusz.kubalewski@...el.com>

Stop dividing the phase_offset value received from firmware. This fault
is present since the initial implementation.
The phase_offset value received from firmware is in 0.01ps resolution.
Dpll subsystem is using the value in 0.001ps, raw value is adjusted
before providing it to the user.

The user can observe the value of phase offset with response to
`pin-get` netlink message of dpll subsystem for an active pin:
$ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/dpll.yaml \
	--do pin-get --json '{"id":2}'

Where example of correct response would be:
{'board-label': 'C827_0-RCLKA',
 'capabilities': 6,
 'clock-id': 4658613174691613800,
 'frequency': 1953125,
 'id': 2,
 'module-name': 'ice',
 'parent-device': [{'direction': 'input',
                    'parent-id': 6,
                    'phase-offset': -216839550,
                    'prio': 9,
                    'state': 'connected'},
                   {'direction': 'input',
                    'parent-id': 7,
                    'phase-offset': -42930,
                    'prio': 8,
                    'state': 'connected'}],
 'phase-adjust': 0,
 'phase-adjust-max': 16723,
 'phase-adjust-min': -16723,
 'type': 'mux'}

Provided phase-offset value (-42930) shall be divided by the user with
DPLL_PHASE_OFFSET_DIVIDER to get actual value of -42.930 ps.

Before the fix, the response was not correct:
{'board-label': 'C827_0-RCLKA',
 'capabilities': 6,
 'clock-id': 4658613174691613800,
 'frequency': 1953125,
 'id': 2,
 'module-name': 'ice',
 'parent-device': [{'direction': 'input',
                    'parent-id': 6,
                    'phase-offset': -216839,
                    'prio': 9,
                    'state': 'connected'},
                   {'direction': 'input',
                    'parent-id': 7,
                    'phase-offset': -42,
                    'prio': 8,
                    'state': 'connected'}],
 'phase-adjust': 0,
 'phase-adjust-max': 16723,
 'phase-adjust-min': -16723,
 'type': 'mux'}

Where phase-offset value (-42), after division
(DPLL_PHASE_OFFSET_DIVIDER) would be: -0.042 ps.

Fixes: 8a3a565ff210 ("ice: add admin commands to access cgu configuration")
Fixes: 90e1c90750d7 ("ice: dpll: implement phase related callbacks")
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@...el.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@...el.com>
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@...el.com>
Reviewed-by: Paul Menzel <pmenzel@...gen.mpg.de>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@...el.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@...el.com>
---
 drivers/net/ethernet/intel/ice/ice_common.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_common.c b/drivers/net/ethernet/intel/ice/ice_common.c
index 9a6c25f98632..edac34c796ce 100644
--- a/drivers/net/ethernet/intel/ice/ice_common.c
+++ b/drivers/net/ethernet/intel/ice/ice_common.c
@@ -5332,7 +5332,6 @@ ice_aq_get_cgu_dpll_status(struct ice_hw *hw, u8 dpll_num, u8 *ref_state,
 			   u8 *eec_mode)
 {
 	struct ice_aqc_get_cgu_dpll_status *cmd;
-	const s64 nsec_per_psec = 1000LL;
 	struct ice_aq_desc desc;
 	int status;
 
@@ -5348,8 +5347,7 @@ ice_aq_get_cgu_dpll_status(struct ice_hw *hw, u8 dpll_num, u8 *ref_state,
 		*phase_offset = le32_to_cpu(cmd->phase_offset_h);
 		*phase_offset <<= 32;
 		*phase_offset += le32_to_cpu(cmd->phase_offset_l);
-		*phase_offset = div64_s64(sign_extend64(*phase_offset, 47),
-					  nsec_per_psec);
+		*phase_offset = sign_extend64(*phase_offset, 47);
 		*eec_mode = cmd->eec_mode;
 	}
 
-- 
2.41.0