RE: [PATCH v4 5/8] phy: freescale: pcie: Initialize the imx8 pcie standalone phy driver

From: Richard Zhu
Date: Mon Nov 01 2021 - 04:19:30 EST

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> -----Original Message-----
> From: Tim Harvey <tharvey@xxxxxxxxxxxxx>
> Sent: Saturday, October 30, 2021 1:45 AM
> To: Richard Zhu <hongxing.zhu@xxxxxxx>; Marcel Ziswiler
> <marcel.ziswiler@xxxxxxxxxxx>
> Cc: kishon@xxxxxx; vkoul@xxxxxxxxxx; robh@xxxxxxxxxx;
> l.stach@xxxxxxxxxxxxxx; shawnguo@xxxxxxxxxx;
> galak@xxxxxxxxxxxxxxxxxxx; linux-phy@xxxxxxxxxxxxxxxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; dl-linux-imx
> <linux-imx@xxxxxxx>
> Subject: Re: [PATCH v4 5/8] phy: freescale: pcie: Initialize the imx8 pcie
> standalone phy driver
>
> On Fri, Oct 29, 2021 at 1:45 AM Richard Zhu <hongxing.zhu@xxxxxxx>
> wrote:
> >
> >
> > > -----Original Message-----
> > > From: Marcel Ziswiler <marcel.ziswiler@xxxxxxxxxxx>
> > > Sent: Friday, October 29, 2021 4:13 PM
> > > To: kishon@xxxxxx; vkoul@xxxxxxxxxx; robh@xxxxxxxxxx;
> > > l.stach@xxxxxxxxxxxxxx; shawnguo@xxxxxxxxxx;
> tharvey@xxxxxxxxxxxxx;
> > > galak@xxxxxxxxxxxxxxxxxxx; Richard Zhu <hongxing.zhu@xxxxxxx>
> > > Cc: linux-phy@xxxxxxxxxxxxxxxxxxx;
> > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> > > kernel@xxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx;
> > > linux-kernel@xxxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>
> > > Subject: Re: [PATCH v4 5/8] phy: freescale: pcie: Initialize the
> > > imx8 pcie standalone phy driver
> > >
> > > On Thu, 2021-10-28 at 15:27 +0800, Richard Zhu wrote:
> > > > Add the standalone i.MX8 PCIe PHY driver.
> > > >
> > > > Signed-off-by: Richard Zhu <hongxing.zhu@xxxxxxx>
> > > > Tested-by: Marcel Ziswiler <marcel.ziswiler@xxxxxxxxxxx>
> > >
> > > Unfortunately, this version no longer works for our
> > > IMX8_PCIE_REFCLK_PAD_OUTPUT use-case. Further comments in-
> lined
> > > below.
> > >
> > [Richard Zhu] Sorry to hear about that. Then, it seems that this bit
> > should be set anyway.
> > It's hard to understand this bit refer to the RM document. Sigh ☹.
> > Would set the AUX_EN bit later.
> >
> > > > ---
> > > > drivers/phy/freescale/Kconfig | 9 +
> > > > drivers/phy/freescale/Makefile | 1 +
> > > > drivers/phy/freescale/phy-fsl-imx8m-pcie.c | 234
> > > > +++++++++++++++++++++
> > > > 3 files changed, 244 insertions(+) create mode 100644
> > > > drivers/phy/freescale/phy-fsl-imx8m-pcie.c
> > > >
> > > > diff --git a/drivers/phy/freescale/Kconfig
> > > > b/drivers/phy/freescale/Kconfig index 320630ffe3cd..de9ee7020f76
> > > > 100644
> > > > --- a/drivers/phy/freescale/Kconfig
> > > > +++ b/drivers/phy/freescale/Kconfig
> > > > @@ -14,3 +14,12 @@ config PHY_MIXEL_MIPI_DPHY
> > > > help
> > > > Enable this to add support for the Mixel DSI PHY as
> > > found
> > > > on NXP's i.MX8 family of SOCs.
> > > > +
> > > > +config PHY_FSL_IMX8M_PCIE
> > > > + tristate "Freescale i.MX8 PCIE PHY"
> > >
> > > Above description is missing the M as in i.MX 8M.
> > [Richard Zhu] Okay, would be added later.
> > Thanks.
> >
> > >
> > > > + depends on OF && HAS_IOMEM
> > > > + select GENERIC_PHY
> > > > + default ARCH_MXC && ARM64
> > > > + help
> > > > + Enable this to add support for the PCIE PHY as found on
> > > > + i.MX8M family of SOCs.
> > > > diff --git a/drivers/phy/freescale/Makefile
> > > > b/drivers/phy/freescale/Makefile index
> 1d02e3869b45..55d07c742ab0
> > > > 100644
> > > > --- a/drivers/phy/freescale/Makefile
> > > > +++ b/drivers/phy/freescale/Makefile
> > > > @@ -1,3 +1,4 @@
> > > > # SPDX-License-Identifier: GPL-2.0-only
> > > > obj-$(CONFIG_PHY_FSL_IMX8MQ_USB) +=
> > > phy-fsl-imx8mq-usb.o
> > > > obj-$(CONFIG_PHY_MIXEL_MIPI_DPHY) +=
> > > phy-fsl-imx8-mipi-dphy.o
> > > > +obj-$(CONFIG_PHY_FSL_IMX8M_PCIE) +=
> > > phy-fsl-imx8m-pcie.o
> > > > diff --git a/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
> > > > b/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
> > > > new file mode 100644
> > > > index 000000000000..4b4402eaddcc
> > > > --- /dev/null
> > > > +++ b/drivers/phy/freescale/phy-fsl-imx8m-pcie.c
> > > > @@ -0,0 +1,234 @@
> > > > +// SPDX-License-Identifier: GPL-2.0+
> > > > +/*
> > > > + * Copyright 2021 NXP
> > > > + */
> > > > +
> > > > +#include <linux/clk.h>
> > > > +#include <linux/io.h>
> > > > +#include <linux/iopoll.h>
> > > > +#include <linux/delay.h>
> > > > +#include <linux/mfd/syscon.h>
> > > > +#include <linux/mfd/syscon/imx7-iomuxc-gpr.h>
> > > > +#include <linux/module.h>
> > > > +#include <linux/phy/phy.h>
> > > > +#include <linux/platform_device.h> #include <linux/regmap.h>
> > > > +#include <linux/reset.h> #include
> > > > +<dt-bindings/phy/phy-imx8-pcie.h>
> > > > +
> > > > +#define IMX8MM_PCIE_PHY_CMN_REG061 0x184 #define
> > > > +ANA_PLL_CLK_OUT_TO_EXT_IO_EN BIT(0) #define
> > > > +IMX8MM_PCIE_PHY_CMN_REG062 0x188 #define
> > > > +ANA_PLL_CLK_OUT_TO_EXT_IO_SEL BIT(3) #define
> > > > +IMX8MM_PCIE_PHY_CMN_REG063 0x18C #define
> > > > +AUX_PLL_REFCLK_SEL_SYS_PLL GENMASK(7, 6) #define
> > > > +IMX8MM_PCIE_PHY_CMN_REG064 0x190
> > > #define ANA_AUX_RX_TX_SEL_TX
> > > > +BIT(7)
> > > #define ANA_AUX_RX_TERM_GND_EN BIT(3)
> > > #define
> > > > +ANA_AUX_TX_TERM BIT(2) #define
> > > > +IMX8MM_PCIE_PHY_CMN_REG065 0x194
> > > #define ANA_AUX_RX_TERM
> > > > +(BIT(7) | BIT(4))
> > > #define ANA_AUX_TX_LVL
> > > > +GENMASK(3, 0) #define
> > > IMX8MM_PCIE_PHY_CMN_REG75 0x1D4 #define
> > > > +PCIE_PHY_CMN_REG75_PLL_DONE 0x3 #define
> > > PCIE_PHY_TRSV_REG5
> > > > +0x414 #define PCIE_PHY_TRSV_REG5_GEN1_DEEMP 0x2D
> #define
> > > > +PCIE_PHY_TRSV_REG6 0x418 #define
> > > > +PCIE_PHY_TRSV_REG6_GEN2_DEEMP 0xF
> > > > +
> > > > +#define IMX8MM_GPR_PCIE_REF_CLK_SEL GENMASK(25, 24)
> > > #define
> > > > +IMX8MM_GPR_PCIE_REF_CLK_PLL
> > > > +FIELD_PREP(IMX8MM_GPR_PCIE_REF_CLK_SEL, 0x3) #define
> > > > +IMX8MM_GPR_PCIE_REF_CLK_EXT
> > > > +FIELD_PREP(IMX8MM_GPR_PCIE_REF_CLK_SEL, 0x2) #define
> > > > +IMX8MM_GPR_PCIE_AUX_EN BIT(19) #define
> > > > +IMX8MM_GPR_PCIE_CMN_RST BIT(18)
> > > #define
> > > > +IMX8MM_GPR_PCIE_POWER_OFF BIT(17) #define
> > > IMX8MM_GPR_PCIE_SSC_EN
> > > > +BIT(16) #define
> > > IMX8MM_GPR_PCIE_AUX_EN_OVERRIDE BIT(9)
> > > > +
> > > > +struct imx8_pcie_phy {
> > > > + void __iomem *base;
> > > > + struct clk *clk;
> > > > + struct phy *phy;
> > > > + struct regmap *iomuxc_gpr;
> > > > + struct reset_control *reset;
> > > > + u32 refclk_pad_mode;
> > > > + u32 tx_deemph_gen1;
> > > > + u32 tx_deemph_gen2;
> > > > + bool clkreq_unused; };
> > > > +
> > > > +static int imx8_pcie_phy_init(struct phy *phy) {
> > > > + int ret;
> > > > + u32 val, pad_mode;
> > > > + struct imx8_pcie_phy *imx8_phy = phy_get_drvdata(phy);
> > > > +
> > > > + reset_control_assert(imx8_phy->reset);
> > > > +
> > > > + pad_mode = imx8_phy->refclk_pad_mode;
> > > > + /* Set AUX_EN_OVERRIDE 1'b0, when the CLKREQ# isn't
> > > hooked */
> > > > + regmap_update_bits(imx8_phy->iomuxc_gpr,
> > > IOMUXC_GPR14,
> > > >
> > > + IMX8MM_GPR_PCIE_AUX_EN_
> > > OVERRIDE,
> > > > + imx8_phy->clkreq_unused ?
> > > > + 0 :
> > > IMX8MM_GPR_PCIE_AUX_EN_OVERRIDE);
> > > > + regmap_update_bits(imx8_phy->iomuxc_gpr,
> > > IOMUXC_GPR14,
> > > > + IMX8MM_GPR_PCIE_AUX_EN,
> > > > + pad_mode ==
> > > IMX8_PCIE_REFCLK_PAD_INPUT ?
> > > > + IMX8MM_GPR_PCIE_AUX_EN :
> > > 0);
> > >
> > > V3 had IMX8MM_GPR_PCIE_AUX_EN always enabled. Turns out V4
> stopped
> > > working for our output use-case as it only enables it for the input
> > > use-case. If I enable this one always it starts working again.
> > [Richard Zhu] See my comment above.
> > Sorry to bring the regression on your board.
> >
>
> Marcel,
>
> Your board does not use an external clk, but does it hook up CLKREQ#
> from the socket to either I2C4_SCL or UART4_RXD and pin muxed as
> such?
>
> For my board that uses an external clk and does not connect CLKREQ# to
> the IMX8MM I need to disable that bit. As Richard says we have invalid
> documentation for these bits unfortunately which is not helping.
>
> Richard, when we do figure out proper documentation for these bits I
> suggest you also add a comment block right above their #defines in the
> phy driver with the correct documentation to avoid future confusion.
> NXP has had so many mistakes in the various IMX8M RM's and I fear they
> will never get fixed.
[Richard Zhu] Hi Tim:
I took look at the validation codes, and found that the AUX_EN is always
set to be 1b'1. Whatever the reference clock mode is selected.
I'm sending a query email to design team, but I'm not sure I can get response
in time.
Can you help to take a double tests at your board when AUX_EN(bit19 of GPR14)
is set to be 1b'1 firstly?
Thanks in advanced.

BR
Richard
>
> Best regards,
>
> Tim

Next message: Michael S. Tsirkin: "Re: [PATCH v7 0/9] vDPA driver for Alibaba ENI"
Previous message: Michael S. Tsirkin: "Re: [PATCH v7 9/9] eni_vdpa: alibaba: fix Kconfig typo"
Next in thread: Tim Harvey: "Re: [PATCH v4 5/8] phy: freescale: pcie: Initialize the imx8 pcie standalone phy driver"
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