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41 lines
1.3 KiB
ReStructuredText
41 lines
1.3 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
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=======================================
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stmmac (synopsys dwmac) devlink support
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=======================================
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This document describes the devlink features implemented by the ``stmmac``
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device driver.
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Parameters
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==========
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The ``stmmac`` driver implements the following driver-specific parameters.
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.. list-table:: Driver-specific parameters implemented
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:widths: 5 5 5 85
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* - Name
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- Type
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- Mode
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- Description
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* - ``phc_coarse_adj``
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- Boolean
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- runtime
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- Enable the Coarse timestamping mode, as defined in the DWMAC TRM.
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A detailed explanation of this timestamping mode can be found in the
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Socfpga Functionnal Description [1].
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In Coarse mode, the ptp clock is expected to be fed by a high-precision
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clock that is externally adjusted, and the subsecond increment used for
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timestamping is set to 1/ptp_clock_rate.
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In Fine mode (i.e. Coarse mode == false), the ptp clock frequency is
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continuously adjusted, but the subsecond increment is set to
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2/ptp_clock_rate.
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Coarse mode is suitable for PTP Grand Master operation. If unsure, leave
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the parameter to False.
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[1] https://www.intel.com/content/www/us/en/docs/programmable/683126/21-2/functional-description-of-the-emac.html
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