ice: fix ready bitmap check for non-E822 devices

ice: fix ready bitmap check for non-E822 devices

The E800 hardware (apart from E810) has a ready bitmap for the PHY
indicating which timestamp slots currently have an outstanding timestamp
waiting to be read by software.

This bitmap is checked in multiple places using the
ice_get_phy_tx_tstamp_ready():

 * ice_ptp_process_tx_tstamp() calls it to determine which timestamps to
   attempt reading from the PHY
 * ice_ptp_tx_tstamps_pending() calls it in a loop at the end of the
   miscellaneous IRQ to check if new timestamps came in while the interrupt
   handler was executing.
 * ice_ptp_maybe_trigger_tx_interrupt() calls it in the auxiliary work task
   to trigger a software interrupt in the event that the hardware logic
   gets stuck.

For E82X devices, multiple PHYs share the same block, and the parameter
passed to the ready bitmap is a block number associated with the given
port. For E825-C devices, the PHYs have their own independent blocks and do
not share, so the parameter passed needs to be the port number. For E810
devices, the ice_get_phy_tx_tstamp_ready() always returns all 1s regardless
of what port, since this hardware does not have a ready bitmap. Finally,
for E830 devices, each PF has its own ready bitmap accessible via register,
and the block parameter is unused.

The first call correctly uses the Tx timestamp tracker block parameter to
check the appropriate timestamp block. This works because the tracker is
setup correctly for each timestamp device type.

The second two callers behave incorrectly for all device types other than
the older E822 devices. They both iterate in a loop using
ICE_GET_QUAD_NUM() which is a macro only used by E822 devices. This logic
is incorrect for devices other than the E822 devices.

For E810 the calls would always return true, causing E810 devices to always
attempt to trigger a software interrupt even when they have no reason to.
For E830, this results in duplicate work as the ready bitmap is checked
once per number of quads. Finally, for E825-C, this results in the pending
checks failing to detect timestamps on ports other than the first two.

Fix this by introducing a new hardware API function to ice_ptp_hw.c,
ice_check_phy_tx_tstamp_ready(). This function will check if any timestamps
are available and returns a positive value if any timestamps are pending.
For E810, the function always returns false, so that the re-trigger checks
never happen. For E830, check the ready bitmap just once. For E82x
hardware, check each quad. Finally, for E825-C, check every port.

The interface function returns an integer to enable reporting of error code
if the driver is unable read the ready bitmap. This enables callers to
handle this case properly. The previous implementation assumed that
timestamps are available if they failed to read the bitmap. This is
problematic as it could lead to continuous software IRQ triggering if the
PHY timestamp registers somehow become inaccessible.

This change is especially important for E825-C devices, as the missing
checks could leave a window open where a new timestamp could arrive while
the existing timestamps aren't completed. As a result, the hardware
threshold logic would not trigger a new interrupt. Without the check, the
timestamp is left unhandled, and new timestamps will not cause an interrupt
again until the timestamp is handled. Since both the interrupt check and
the backup check in the auxiliary task do not function properly, the device
may have Tx timestamps permanently stuck failing on a given port.

The faulty checks originate from commit d938a8cca88a ("ice: Auxbus devices
& driver for E822 TS") and commit 712e876371f8 ("ice: periodically kick Tx
timestamp interrupt"), however at the time of the original coding, both
functions only operated on E822 hardware. This is no longer the case, and
hasn't been since the introduction of the ETH56G PHY model in commit
7cab44f1c35f ("ice: Introduce ETH56G PHY model for E825C products")

Fixes: 7cab44f1c35f ("ice: Introduce ETH56G PHY model for E825C products")
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Reviewed-by: Petr Oros <poros@redhat.com>
Tested-by: Sunitha Mekala <sunithax.d.mekala@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260420-jk-iwl-net-2026-04-20-ptp-e825c-phy-interrupt-fixes-v1-3-bc2240f42251@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>