On Sun, Nov 18, 2018 at 11:07 PM Richard Zhu <hongxing....@nxp.com> wrote: > > Hi Andrey: > Thanks for your patch-set. > I have comment about the L1SS implementation below. > It's better to figure out one method to fix it. > > BR > Richard > > > -----Original Message----- > > From: Andrey Smirnov [mailto:andrew.smir...@gmail.com] > > Sent: 2018年11月18日 2:12 > > To: linux-kernel@vger.kernel.org > > Cc: Andrey Smirnov <andrew.smir...@gmail.com>; bhelg...@google.com; > > Fabio Estevam <fabio.este...@nxp.com>; cphe...@gmail.com; > > l.st...@pengutronix.de; Leonard Crestez <leonard.cres...@nxp.com>; > > Aisheng DONG <aisheng.d...@nxp.com>; Richard Zhu > > <hongxing....@nxp.com>; dl-linux-imx <linux-...@nxp.com>; > > linux-arm-ker...@lists.infradead.org; linux-...@vger.kernel.org > > Subject: [PATCH 3/3] PCI: imx: Add support for i.MX8MQ > > > > Cc: bhelg...@google.com > > Cc: Fabio Estevam <fabio.este...@nxp.com> > > Cc: cphe...@gmail.com > > Cc: l.st...@pengutronix.de > > Cc: Leonard Crestez <leonard.cres...@nxp.com> > > Cc: "A.s. Dong" <aisheng.d...@nxp.com> > > Cc: Richard Zhu <hongxing....@nxp.com> > > Cc: linux-...@nxp.com > > Cc: linux-arm-ker...@lists.infradead.org > > Cc: linux-kernel@vger.kernel.org > > Cc: linux-...@vger.kernel.org > > Signed-off-by: Andrey Smirnov <andrew.smir...@gmail.com> > > --- > > drivers/pci/controller/dwc/Kconfig | 2 +- > > drivers/pci/controller/dwc/pci-imx6.c | 117 ++++++++++++++++++++++++-- > > 2 files changed, 113 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/pci/controller/dwc/Kconfig > > b/drivers/pci/controller/dwc/Kconfig > > index 91b0194240a5..2b139acccf32 100644 > > --- a/drivers/pci/controller/dwc/Kconfig > > +++ b/drivers/pci/controller/dwc/Kconfig > > @@ -90,7 +90,7 @@ config PCI_EXYNOS > > > > config PCI_IMX6 > > bool "Freescale i.MX6 PCIe controller" > > - depends on SOC_IMX6Q || (ARM && COMPILE_TEST) > > + depends on SOC_IMX8MQ || SOC_IMX6Q || (ARM && COMPILE_TEST) > > depends on PCI_MSI_IRQ_DOMAIN > > select PCIE_DW_HOST > > > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c > > b/drivers/pci/controller/dwc/pci-imx6.c > > index 3c3002861d25..8d1f310e41a6 100644 > > --- a/drivers/pci/controller/dwc/pci-imx6.c > > +++ b/drivers/pci/controller/dwc/pci-imx6.c > > @@ -8,6 +8,7 @@ > > * Author: Sean Cross <x...@kosagi.com> > > */ > > > > +#include <linux/bitfield.h> > > #include <linux/clk.h> > > #include <linux/delay.h> > > #include <linux/gpio.h> > > @@ -30,6 +31,14 @@ > > > > #include "pcie-designware.h" > > > > +#define IMX8MQ_PCIE_LINK_CAP_REG_OFFSET 0x7C > > +#define IMX8MQ_PCIE_LINK_CAP_L1EL_64US (0x6 << 15) > > + > > +#define IMX8MQ_GPR_PCIE_REF_USE_PAD BIT(9) > > +#define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN BIT(10) > > +#define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE BIT(11) > > + > > + > > #define to_imx6_pcie(x) dev_get_drvdata((x)->dev) > > > > enum imx6_pcie_variants { > > @@ -37,6 +46,7 @@ enum imx6_pcie_variants { > > IMX6SX, > > IMX6QP, > > IMX7D, > > + IMX8MQ, > > }; > > > > struct imx6_pcie { > > @@ -48,8 +58,10 @@ struct imx6_pcie { > > struct clk *pcie_inbound_axi; > > struct clk *pcie; > > struct regmap *iomuxc_gpr; > > + u32 gpr1x; > > struct reset_control *pciephy_reset; > > struct reset_control *apps_reset; > > + struct reset_control *apps_clk_req; > > struct reset_control *turnoff_reset; > > enum imx6_pcie_variants variant; > > u32 tx_deemph_gen1; > > @@ -59,6 +71,7 @@ struct imx6_pcie { > > u32 tx_swing_low; > > int link_gen; > > struct regulator *vpcie; > > + u32 device_type[2]; > > }; > > > > /* Parameters for the waiting for PCIe PHY PLL to lock on i.MX7 */ @@ > > -245,7 +258,8 @@ static void imx6_pcie_reset_phy(struct imx6_pcie > > *imx6_pcie) { > > u32 tmp; > > > > - if (imx6_pcie->variant == IMX7D) > > + if (imx6_pcie->variant == IMX7D || > > + imx6_pcie->variant == IMX8MQ) > > return; > > > > pcie_phy_read(imx6_pcie, PHY_RX_OVRD_IN_LO, &tmp); @@ -261,6 > > +275,7 @@ static void imx6_pcie_reset_phy(struct imx6_pcie *imx6_pcie) > > pcie_phy_write(imx6_pcie, PHY_RX_OVRD_IN_LO, tmp); } > > > > +#ifdef CONFIG_ARM > > /* Added for PCI abort handling */ > > static int imx6q_pcie_abort_handler(unsigned long addr, > > unsigned int fsr, struct pt_regs *regs) @@ -294,6 +309,7 @@ > > static > > int imx6q_pcie_abort_handler(unsigned long addr, > > > > return 1; > > } > > +#endif > > > > static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie) > > { @@ -301,6 +317,7 @@ static void imx6_pcie_assert_core_reset(struct > > imx6_pcie *imx6_pcie) > > > > switch (imx6_pcie->variant) { > > case IMX7D: > > + case IMX8MQ: /* FALLTHROUGH */ > > reset_control_assert(imx6_pcie->pciephy_reset); > > reset_control_assert(imx6_pcie->apps_reset); > > break; > > @@ -369,6 +386,18 @@ static int imx6_pcie_enable_ref_clk(struct > > imx6_pcie *imx6_pcie) > > break; > > case IMX7D: > > break; > > + case IMX8MQ: > > + /* > > + * Set the over ride low and enabled > > + * make sure that REF_CLK is turned on. > > + */ > > + regmap_update_bits(imx6_pcie->iomuxc_gpr, imx6_pcie->gpr1x, > > + IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE, > > + 0); > > + regmap_update_bits(imx6_pcie->iomuxc_gpr, imx6_pcie->gpr1x, > > + IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN, > > + IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE_EN); > > + break; > > } > > > > return ret; > > @@ -397,6 +426,7 @@ static void imx6_pcie_deassert_core_reset(struct > > imx6_pcie *imx6_pcie) { > > struct dw_pcie *pci = imx6_pcie->pci; > > struct device *dev = pci->dev; > > + unsigned int val; > > int ret; > > > > if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie->vpcie)) { @@ > > -445,6 +475,29 @@ static void imx6_pcie_deassert_core_reset(struct > > imx6_pcie *imx6_pcie) > > } > > > > switch (imx6_pcie->variant) { > > + case IMX8MQ: > > + reset_control_deassert(imx6_pcie->pciephy_reset); > > + udelay(100); > > + /* > > + * Configure the CLK_REQ# high, let the L1SS > > + * automatically controlled by HW. > > + */ > > + reset_control_assert(imx6_pcie->apps_clk_req); > > + > > + /* > > + * Configure the L1 latency of rc to less than 64us > > + * Otherwise, the L1/L1SUB wouldn't be enable by ASPM. > > + */ > > + val = dw_pcie_readl_dbi(imx6_pcie->pci, > > + SZ_1M + > > + IMX8MQ_PCIE_LINK_CAP_REG_OFFSET); > > + val &= ~PCI_EXP_LNKCAP_L1EL; > > + val |= IMX8MQ_PCIE_LINK_CAP_L1EL_64US; > > + dw_pcie_writel_dbi(imx6_pcie->pci, > > + SZ_1M + > > + IMX8MQ_PCIE_LINK_CAP_REG_OFFSET, > > + val); > > + break; > > case IMX7D: > > reset_control_deassert(imx6_pcie->pciephy_reset); > > imx7d_pcie_wait_for_phy_pll_lock(imx6_pcie); > > @@ -483,6 +536,15 @@ static void imx6_pcie_deassert_core_reset(struct > > imx6_pcie *imx6_pcie) static void imx6_pcie_init_phy(struct imx6_pcie > > *imx6_pcie) { > > switch (imx6_pcie->variant) { > > + case IMX8MQ: > > + /* > > + * TODO: Currently this code assumes external > > + * oscillator is being used > > + */ > > + regmap_update_bits(imx6_pcie->iomuxc_gpr, imx6_pcie->gpr1x, > > + IMX8MQ_GPR_PCIE_REF_USE_PAD, > > + IMX8MQ_GPR_PCIE_REF_USE_PAD); > > + break; > > case IMX7D: > > regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, > > IMX7D_GPR12_PCIE_PHY_REFCLK_SEL, 0); @@ > > -519,7 +581,8 @@ static void imx6_pcie_init_phy(struct imx6_pcie > > *imx6_pcie) > > } > > > > regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, > > - IMX6Q_GPR12_DEVICE_TYPE, PCI_EXP_TYPE_ROOT_PORT << > > 12); > > + imx6_pcie->device_type[0], > > + imx6_pcie->device_type[1]); > > } > > > > static int imx6_setup_phy_mpll(struct imx6_pcie *imx6_pcie) @@ -528,7 > > +591,8 @@ static int imx6_setup_phy_mpll(struct imx6_pcie *imx6_pcie) > > int mult, div; > > u32 val; > > > > - if (imx6_pcie->variant == IMX7D) > > + if (imx6_pcie->variant == IMX7D || > > + imx6_pcie->variant == IMX8MQ) > > return 0; > > > > switch (phy_rate) { > > @@ -616,6 +680,7 @@ static void imx6_pcie_ltssm_enable(struct device > > *dev) > > IMX6Q_GPR12_PCIE_CTL_2); > > break; > > case IMX7D: > > + case IMX8MQ: /* FALLTHROUGH */ > > reset_control_deassert(imx6_pcie->apps_reset); > > break; > > } > > @@ -798,10 +863,24 @@ static void imx6_pcie_clk_disable(struct imx6_pcie > > *imx6_pcie) > > clk_disable_unprepare(imx6_pcie->pcie_phy); > > clk_disable_unprepare(imx6_pcie->pcie_bus); > > > > - if (imx6_pcie->variant == IMX7D) { > > + switch (imx6_pcie->variant) { > > + case IMX7D: > > regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12, > > IMX7D_GPR12_PCIE_PHY_REFCLK_SEL, > > IMX7D_GPR12_PCIE_PHY_REFCLK_SEL); > > + break; > > + /* > > + * Disable the override. Configure the CLK_REQ# high, let the > > + * L1SS automatically controlled by HW when link is up. > > + * Otherwise, turn off the REF_CLK to save power consumption. > > + */ > [Richard Zhu] About the L1SS support, there is a back-compatible issue. > When one none-L1SS capability EP device is used in one HW design solution. > In this case, EP device wouldn't manipulated its own CLK_REQ#. > The CLK_REQ# would be high when the override_en is disabled here. > That means the REFCLK would be turned off abnormally. > System would have problem when the REFCLK of PCIe is turned off abnormally > after link is up. >
I don't have a lot of expertise in this area, so please take my comment with a grain of salt. The way I understand it, is in legacy systems that do not support L1SS with CLKREQ that feature shouldn't be enabled/used. Unless I've missed something, I think it should be possible to do so and disable the feature by configuring corresponding CLKREQ_B pad as GPIO and adding a GPIO hog node to pull CLKREQ low. Do you see any problems with this approach? Regardless though, I wasn't really planning on including PM support in this series. The code in question shouldn't even be in the patch since it'll never be executed because imx6_pcie_clk_disable() is only called by imx6_pcie_suspend_noirq() which is a no-op on all variants except i.MX7D. I'll drop all of the unused PM-related bits I missed from the series and we can add them later in a separate submission. Thanks, Andrey Smirnov
