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Merge branch 'dwmac-meson8b-clock-fixes-for-Meson8b'
Martin Blumenstingl says: ==================== dwmac-meson8b: clock fixes for Meson8b this series is now successfully tested, thus we think it's ready to be applied to your net-next tree. Emiliano reported [0] that he couldn't get dwmac-meson8b to work on his Odroid-C1. This is the (hopefully) final version of this series, which was successfully tested. Due to the fact that the public S805/S905/S912 datasheets all seem to be outdated regarding the description of the PRG_ETH0 (also called PRG_ETHERNET_ADDR0) register Linus Lüssing offered to help testing with an oscilloscope and an Odroid-C1. I would like to say HUGE thanks to him at this point as he spent hours figuring out the effects of the bits that are (though to be) relevant to get Ethernet working on the Odroid-C1. We tested three scenarios, all based on version 3 of this series: 1) MPLL2 at ~500MHz, m250_div set to 1, bit 10 enabled this resulted in a clock rate twice as high as expected at the RGMII TX clock pin (250MHz instead of 125MHz for Gbit connections and 50MHz instead of 25MHz for 100Mbit/s connections). it did not change the rate at the XTAL_IN pin of PHY (which stayed consistenly at 25MHz) 2) MPLL2 at ~250MHz, m250_div set to 1, bit 10 disabled the oscilloscope shows "no clock" for the RGMII TX clock pin at it's highest resolution (and random rates at lower resolutions). XTAL_IN is still at 25MHz 3) MPLL2 at ~250MHz, m250_div set to 1, bit 10 enabled this resulted in a 125MHz signal at the RGMII TX clock pin for Gbit speeds and 25MHz for 100Mbit/s - both values are as expected. The rate on the XTAL_IN pin was at 25MHz -> boot-logs (with the PRG_ETH0 register value) and screenshots from the readings of the oscilloscope can be found at: https://metameute.de/~tux/linux/amlogic/odroidc1/ethernet/ Version 4 of this series is based on the results from Linus Lüssing's help with the oscilloscope and Odroid-C1. Unfortunately I don't have any Meson8b boards with RGMII PHY so I could only partially test this. @Emiliano: Could you please give this version a try and let me know about the results (preferably with a "Tested-by" if it works)? You obviously still need your two "ARM: dts: meson8b" patches which - add the amlogic,meson8b-dwmac" compatible to meson8b.dtsi - enable Ethernet on the Odroid-C1 (according to your last thest a TX delay of 4ns is required to make it work properly) When testing on Meson8b this also needs a fix for the MPLL clock driver: "clk: meson: mpll: use 64-bit maths in params_from_rate", see: https://patchwork.kernel.org/patch/10131677/ I have tested this myself on a Khadas VIM (GXL SoC, internal RMII PHY) and a Khadas VIM2 (GXM SoC, external RGMII PHY). Both are still working fine (so let's hope that this also fixes your Meson8b issue :)). changes since v4 at [4]: - dropped "RFT" status since Jerome tested this series successfully! - dropped PATCH #2 ("simplify generating the clock names"). I will improve the whole clock registration in a separate series. since that patch didn't really improve anything I dropped it for now - added Jerome's Acked-/Reviewed-/Tested-by's - many thanks! changes since v3 at [3]: - renamed the function PATCH #1 from meson8b_init_rgmii_clk to meson8b_init_rgmii_tx_clk since we now know what the register bits mean - rewrote PATCH #3 because bit 10 is a gate clock and it seems that there is an internal fixed divide-by-2 clock. see the patch description for a detailed explanation - updated the description of PATCH #4 and #5 as the clock we're trying to fix is the "RGMII TX" clock (old version stated that this is the "RGMII clock" or "PHY reference clock"). also updated the numbers in the description now that we have the clock hierarchy right (at least we hope so) changes since v2 at [2]: - added PATCH #2 to make the following patch easier - Emiliano reported that there's currently another bug in the dwmac-meson8b driver which prevents it from working with RGMII PHYs on Meson8b: bit 10 of the PRG_ETH0 register is configures a clock gate (instead of a divide by 5 or divide by 10 clock divider). This has not been visible on GXBB and later due to the input clock which always led to a selection of "divide by 10" (which is done internally in the IP block, but the bit actually means "enable RGMII clock output"). PATCH #3 was added to address this issue. - the commit message of PATCH #4 and #5 (formerly PATCH #2 and #3) were updated and the patch itself rebased because the m25_div clock was removed with the new PATCH #3 (so some of the statements were not valid anymore) changes since v1 at [1]: - changed the subject of the cover-letter to indicate that this is all about the RGMII clock - added PATCH #1 which ensures that we don't unnecessarily change the parent clocks in RMII mode (and also makes the code easier to understand) - changed subject of PATCH #2 (formerly PATCH #1) to state that this is about the RGMII clock - added Jerome's Reviewed-by to PATCH #2 (formerly PATCH #1) - replaced PATCH #3 (formerly PATCH #2) with one that sets CLK_SET_RATE_PARENT on the mux and thus re-configures the MPLL2 clock on Meson8b correctly [0] http://lists.infradead.org/pipermail/linux-amlogic/2017-December/005596.html [1] http://lists.infradead.org/pipermail/linux-amlogic/2017-December/005848.html [2] http://lists.infradead.org/pipermail/linux-amlogic/2017-December/005861.html [3] http://lists.infradead.org/pipermail/linux-amlogic/2017-December/005899.html [4] http://lists.infradead.org/pipermail/linux-amlogic/2018-January/006125.html ==================== Tested-by: Emiliano Ingrassia <[email protected]> Signed-off-by: David S. Miller <[email protected]>
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