[PATCH 1/4] clk: meson8b: keep mpll2 clock enabled
Emiliano Ingrassia
ingrassia at epigenesys.com
Sat Sep 30 10:08:52 PDT 2017
Hi Martin, Hi Jerome,
On Thu, Sep 28, 2017 at 11:29:03PM +0200, Martin Blumenstingl wrote:
> Hi Emiliano, Hi Jerome,
>
> On Thu, Sep 28, 2017 at 5:08 PM, Jerome Brunet <jbrunet at baylibre.com> wrote:
> > On Thu, 2017-09-28 at 11:59 +0200, Emiliano Ingrassia wrote:
> >> Hi Jerome,
> >>
> >> thanks for review!
> >>
> >> On Thu, Sep 28, 2017 at 09:11:49AM +0200, Jerome Brunet wrote:
> >> > On Wed, 2017-09-27 at 12:40 +0200, Emiliano Ingrassia wrote:
> >> > > The mpll2 clock, enabled by the bootloader, is disabled at boot.
> >> > > Enabling ethernet on Odroid-C1+ board leads to DMA initialization failure
> >> > > caused by a timeout on reset.
> >> > > Keeping the mpll2 clock enabled solve this issue.
> >> >
> >> > Shouldn't the DMA driver emable the clocks it needs itself instead ?
> >> > BTW, I'm bit surprised an mpll is used to clock a DMA, is it possible we
> >> > missed
> >> > something here ?
> >> >
> >>
> originally reported on IRC:
> [ 416.293456] meson8b-dwmac c9410000.ethernet eth0: stmmac_hw_setup:
> DMA engine initialization failed
> [ 416.302480] meson8b-dwmac c9410000.ethernet eth0: stmmac_open: Hw
> setup failed
> this issue is mentioned by the stmmac developers - together with a
> hint how to fix it: [0]
>
> >> The mpll2 clocks the meson8b ethernet controller which, as one can suppose,
> >> internally have a DMA engine. If the controller is enabled, the first
> >> operation on hardware is the DMA engine reset which fails if mpll2 is
> >> disabled.
> >
> > I understand. I mentioned that's it strange to use mpll2 because:
> > - On gxbb (and following SoCs), There is 2 clockin sources to the mac: FDIV2 and
> > MPLL2. There is , of course, an mux in the ethernet device to select the clock
> > you need/want.
> > - I would not be surprised if it was the same thing on meson8(b). In such case,
> > I think it is better to use FDIV2.
> I *think* that clock-source 0 (at least on Meson8b) is *NOT* fclk_div2
> Amlogic's Meson8 and Meson8b u-boot GPL kernel sources (see [1] for
> the Odroid-C1 code) configure HHI_GEN_CLK_CNTL to 0xb803, which
> translates to:
> - divide by 2+1 = 3
> - clock enabled
> - parent clock is 0xb (according to the S912 datasheet this is
> fclk_div5 - it may be a different input on Meson8 and Meson8b)
> (taken from the S912 datasheet released by Khadas)
>
> it also enables HHI_MPLL_CNTL6 bit 27 which is "CKEN[4] MPLL output DIV2 enable"
>
> and finally it uses:
> SET_CBUS_REG_MASK(HHI_MPLL_CNTL9, (1638 << 0)
> | (0 << 14) | (1 << 15) | (1 << 14)
> | (5 << 16)
> | (0 << 25) | (0 << 26) | (0 << 30) | (0 << 31));
>
> further up in the S912 datasheet (clock and reset - section 21.1
> overview) one finds:
> MPLL_CLK_OUT_DIV2_GPIO with comment: to GPIOCLK
>
> I assume that this clock is used as "parent" of the internal mux in
> dwmac-meson8b
>
If you take a look at S805 (Meson8b) SoC manual, pag.122, you can read,
in PRG_ETHERNET_ADDR0[9:7] bits description:
"M8Baby internal clock source is mp2_clk_out only."
This seems correct. In fact, if you enable fclk_div2 and keep mpll2
(aka mp2_clk) disabled, the ethernet controller does not work.
So, we can conclude that, for Meson8b, that should be the correct parent
clock for ethernet controller.
> >> Actually the patch not only solves that issue, but also permits the
> >> ethernet controller to work correctly.
> >> The correct solution would be to enable the mpll2 clock from dwmac-meson8b
> >> driver;
> >
> > Indeed.
> > I would prefer that you fix the ethernet driver rather than adding this to the
> > clock driver.
> >
> >
> >> I'm working on this.
> >> In the meantime I release this patch to give others the chance
> >> to use the ethernet controller on Odroid-C1/C1+.
> >>
> >
> > Ok
> Jerome: maybe those MPLL registers mentioned above make sense to you -
> if you have an *idea* what they are about then please let us know :)
>
> Emiliano: there's also a "clkmsr" command in u-boot which *MIGHT* help
> you to find out the actual frequency of a clock
> however, don't blindly trust that output, I had some cases on GXBB
> where I think the clkmsr result didn't match my expectations
>
Thanks for the advice! I'll keep it in mind.
> by the way: on my Meson8m2 board which comes with a RMII PHY I
> attached the u-boot clkmsr output and a dump of the clock registers
>
> >> Regards,
> >>
> >> Emiliano
> thank you for your improvements!
>
Thank you for your suggestions!
Regards,
Emiliano
> >> > >
> >> > > Signed-off-by: Emiliano Ingrassia <ingrassia at epigenesys.com>
> >> > > ---
> >> > > drivers/clk/meson/meson8b.c | 1 +
> >> > > 1 file changed, 1 insertion(+)
> >> > >
> >> > > diff --git a/drivers/clk/meson/meson8b.c b/drivers/clk/meson/meson8b.c
> >> > > index 20ab7190d328..5096539e4a63 100644
> >> > > --- a/drivers/clk/meson/meson8b.c
> >> > > +++ b/drivers/clk/meson/meson8b.c
> >> > > @@ -347,6 +347,7 @@ static struct meson_clk_mpll meson8b_mpll2 = {
> >> > > .ops = &meson_clk_mpll_ops,
> >> > > .parent_names = (const char *[]){ "fixed_pll" },
> >> > > .num_parents = 1,
> >> > > + .flags = (CLK_SET_RATE_NO_REPARENT | CLK_IGNORE_UNUSED),
> >> > > },
> >> > > };
> >> > >
> >
> >
> > _______________________________________________
> > linux-amlogic mailing list
> > linux-amlogic at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-amlogic
>
>
> [0] http://lists.infradead.org/pipermail/linux-arm-kernel/2017-March/492629.html
> [1] https://github.com/hardkernel/u-boot/blob/odroidc-v2011.03/board/hardkernel/odroidc/odroidc-eth.c#L29
> m8m2_n200_v1#clkmsr
> [ 0 MHz] AM_RING_OSC_CLK_OUT0(0)
> [ 0 MHz] AM_RING_OSC_CLK_OUT1(1)
> [ 0 MHz] SYS_PLL_CLK(2)
> [ 0 MHz] DDR_PLL_CLK(3)
> [ 0 MHz] MISC_PLL_CLK(4)
> [ 0 MHz] AUD_PLL_CLK(5)
> [ 216 MHz] VID_PLL_CLK(6)
> [ 142 MHz] CLK81(7)
> [ 54 MHz] CTS_ENCP_CLK(8)
> [ 54 MHz] CTS_ENCL_CLK(9)
> [ 0 MHz] CTS_ENCT_CLK(10)
> [ 0 MHz] CTS_ETH_RMII(11)
> [ 0 MHz] VID2_PLL_CLK(12)
> [ 0 MHz] CTS_AMCLK(13)
> [ 0 MHz] CTS_FEC_CLK_0 (14)
> [ 0 MHz] CTS_FEC_CLK_1 (15)
> [ 0 MHz] CTS_FEC_CLK_2(16)
> [ 0 MHz] CTS_VGHL_PLL_CLK (17)
> [ 75 MHz] CTS_LED_PLL_CLK(18)
> [ 24 MHz] CTS_HDMI_SYS_CLK(19)
> [ 0 MHz] CTS_BTCLK27 (20)
> [ 0 MHz] MOD_AUDIN_AMCLK_I (21)
> [ 0 MHz] MOD_ETH_CLK50_I (22)
> [ 0 MHz] HDMI_CH3_TMDSCLK(23)
> [ 0 MHz] LVDS_FIFO_CLK (24)
> [ 0 MHz] USB_CLK_12MHZ (25)
> [ 0 MHz] SC_CLK_INT(26)
> [ 0 MHz] CTS_ENCI_CL(27)
> [ 1 MHz] CTS_SAR_ADC_CLK (28)
> [ 0 MHz] CTS_VDAC_CLK0(29)
> [ 0 MHz] CTS_DDR_CLK(30)
> [ 0 MHz] CTS_A9_CLK(31)
> [ 0 MHz] CTS_AUDAC_CLKPI(32)
> [ 0 MHz] CTS_SDHC_CLK0(33)
> [ 0 MHz] CTS_SDHC_CLK1(34)
> [ 0 MHz] CTS_MALI_CLK (35)
> [ 27 MHz] CTS_HDMI_TX_PIXEL_CLK(36)
> [ 0 MHz] CTS_VDAC_CLK1(37)
> [ 0 MHz] CTS_VDIN_MEAS_CLK(38)
> [ 0 MHz] CTS_PCM_SCLK(39)
> [ 0 MHz] CTS_PCM_MCLK(40)
> [ 50 MHz] CTS_ETH_RX_TX (41)
> [ 0 MHz] CTS_PWM_D_CLK(42)
> [ 0 MHz] CTS_PWM_C_CLK(43)
> [ 0 MHz] CTS_PWM_B_CLK(44)
> [ 0 MHz] CTS_PWM_A_CLK(45)
> m8m2_n200_v1#md 0xC1104000 0x100
> c1104000: 00000000 00000000 00000000 00000000 ................
> c1104010: 00000000 00000000 00000000 00000000 ................
> c1104020: 00000000 00000000 00000000 01ea9612 ................
> c1104030: 00000000 00000000 00000000 00000000 ................
> c1104040: c00206b6 59c88000 ca463823 0286a027 .......Y#8F.'...
> c1104050: 00003000 00000000 00000000 00000000 .0..............
> c1104060: 00000000 00000000 00000000 00000000 ................
> c1104070: 00000000 00000000 00000000 00000000 ................
> c1104080: 00000000 00000000 00000000 00000000 ................
> c1104090: 00000000 00000000 00000000 00000000 ................
> c11040a0: 00000000 00000000 00000000 00000000 ................
> c11040b0: 00000000 00000000 00000000 00000000 ................
> c11040c0: 00000000 00000000 00000000 00000000 ................
> c11040d0: 00000000 00000000 00000000 00000000 ................
> c11040e0: 00000000 00000000 00000000 00000384 ................
> c11040f0: 00000000 00000000 00000000 00000000 ................
> c1104100: ffff00f3 00000000 00000000 00000000 ................
> c1104110: 00000000 00000000 00000000 00000000 ................
> c1104120: 00000000 00000000 10000101 00000000 ................
> c1104130: 00010000 00000000 00000000 00000000 ................
> c1104140: ffffffff ffffffff ffffffff 00000000 ................
> c1104150: ffffffff 000000ff 00000000 800016a2 ................
> c1104160: 00000000 10000103 00000000 00000000 ................
> c1104170: 00000000 0000e185 00000004 00080007 ................
> c1104180: 00000000 00000000 00000000 00000000 ................
> c1104190: 00000004 000000ff 00010853 000000b1 ........S.......
> c11041a0: 00000000 00000000 00000000 00000000 ................
> c11041b0: 00000000 00000000 00000000 00000700 ................
> c11041c0: 00000000 00000000 00000000 00010100 ................
> c11041d0: 00000000 00000000 00000000 00000000 ................
> c11041e0: 00000000 00000000 00000000 00000000 ................
> c11041f0: 00000000 00000000 00000000 00000000 ................
> c1104200: 00000000 00000000 00000000 00000000 ................
> c1104210: 00000000 00000000 00000000 00000000 ................
> c1104220: 00000000 00000000 00000000 00000000 ................
> c1104230: 00000000 00000000 00000000 00000000 ................
> c1104240: 00000000 00000000 00000000 00000000 ................
> c1104250: 00000b00 00000000 00000000 00000501 ................
> c1104260: 00000000 00000000 00000000 00000000 ................
> c1104270: 00000000 30000000 00000000 00000000 .......0........
> c1104280: c00009a9 59c80000 ca45b822 00014007 .......Y".E.. at ..
> c1104290: b5500e1a f4454545 00000000 00000000 ..P.EEE.........
> c11042a0: 00000000 00000000 00000000 00000000 ................
> c11042b0: 00000000 00000000 00000000 00000000 ................
> c11042c0: 00000000 00000000 00000000 00000000 ................
> c11042d0: 00000000 00000000 00000000 00000000 ................
> c11042e0: 00000000 00000000 00000000 00000000 ................
> c11042f0: 00000000 00000001 00000000 00000000 ................
> c1104300: c1200232 5ac82000 8e452015 0001d40c 2. .. .Z. E.....
> c1104310: 00000870 00000000 00000100 00180007 p...............
> c1104320: c0080436 59c88000 ca49b022 0023b100 6......Y".I...#.
> c1104330: 00016385 00000003 00000000 00000000 .c..............
> c1104340: 00000000 00000003 001e0000 00000000 ................
> c1104350: 00000000 00000000 00ffffff 00000000 ................
> c1104360: 00000000 00000000 00000000 00000000 ................
> c1104370: 00000000 007f0000 00000000 02000000 ................
> c1104380: 21001001 0430a800 00000000 00000000 ...!..0.........
> c1104390: 00000000 00000002 00000000 00000000 ................
> c11043a0: 00000000 00000000 00000000 00000000 ................
> c11043b0: 00000000 00000000 00000000 00000000 ................
> c11043c0: 00000000 00000000 00000000 00000000 ................
> c11043d0: 00000000 00000000 00000000 00000000 ................
> c11043e0: 00000000 00000000 00000000 00000000 ................
> c11043f0: 00000000 00000000 00000000 00000000 ................
> m8m2_n200_v1#
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