Re: [PATCH V7 14/15] PCI: tegra: Add Tegra194 PCIe support

[Thierry Reding <thierry.reding@gmail.com>]

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On Wed, May 22, 2019 at 05:35:50PM +0530, Vidya Sagar wrote:
> On 5/21/2019 5:11 PM, Thierry Reding wrote:
> > On Fri, May 17, 2019 at 06:08:45PM +0530, Vidya Sagar wrote:
> > > Add support for Synopsys DesignWare core IP based PCIe host controller
> > > present in Tegra194 SoC.
> > > 
> > > Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
> > > ---
> > > Changes since [v6]:
> > > * Removed code around "nvidia,disable-aspm-states" DT property
> > > * Refactored code to remove code duplication
> > > 
> > > Changes since [v5]:
> > > * Addressed review comments from Thierry
> > > 
> > > Changes since [v4]:
> > > * None
> > > 
> > > Changes since [v3]:
> > > * None
> > > 
> > > Changes since [v2]:
> > > * Changed 'nvidia,init-speed' to 'nvidia,init-link-speed'
> > > * Changed 'nvidia,pex-wake' to 'nvidia,wake-gpios'
> > > * Removed .runtime_suspend() & .runtime_resume() implementations
> > > 
> > > Changes since [v1]:
> > > * Made CONFIG_PCIE_TEGRA194 as 'm' by default from its previous 'y' state
> > > * Modified code as per changes made to DT documentation
> > > * Refactored code to address Bjorn & Thierry's review comments
> > > * Added goto to avoid recursion in tegra_pcie_dw_host_init() API
> > > * Merged .scan_bus() of dw_pcie_host_ops implementation to tegra_pcie_dw_host_init() API
> > > 
> > >   drivers/pci/controller/dwc/Kconfig         |   10 +
> > >   drivers/pci/controller/dwc/Makefile        |    1 +
> > >   drivers/pci/controller/dwc/pcie-tegra194.c | 1620 ++++++++++++++++++++
> > >   3 files changed, 1631 insertions(+)
> > >   create mode 100644 drivers/pci/controller/dwc/pcie-tegra194.c
> > > 
> > > diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
> > > index a6ce1ee51b4c..c5d71d5d26a0 100644
> > > --- a/drivers/pci/controller/dwc/Kconfig
> > > +++ b/drivers/pci/controller/dwc/Kconfig
> > > @@ -220,6 +220,16 @@ config PCI_MESON
> > >   	  and therefore the driver re-uses the DesignWare core functions to
> > >   	  implement the driver.
> > > +config PCIE_TEGRA194
> > > +	tristate "NVIDIA Tegra194 (and later) PCIe controller"
> > > +	depends on (TEGRA_BPMP && ARCH_TEGRA) || COMPILE_TEST
> > > +	depends on PCI_MSI_IRQ_DOMAIN
> > > +	select PCIE_DW_HOST
> > > +	select PHY_TEGRA194_PCIE_P2U
> > > +	help
> > > +	  Say Y here if you want support for DesignWare core based PCIe host
> > > +	  controller found in NVIDIA Tegra194 SoC.
> > > +
> > >   config PCIE_UNIPHIER
> > >   	bool "Socionext UniPhier PCIe controllers"
> > >   	depends on ARCH_UNIPHIER || COMPILE_TEST
> > > diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
> > > index b085dfd4fab7..b30336181d46 100644
> > > --- a/drivers/pci/controller/dwc/Makefile
> > > +++ b/drivers/pci/controller/dwc/Makefile
> > > @@ -15,6 +15,7 @@ obj-$(CONFIG_PCIE_ARTPEC6) += pcie-artpec6.o
> > >   obj-$(CONFIG_PCIE_KIRIN) += pcie-kirin.o
> > >   obj-$(CONFIG_PCIE_HISI_STB) += pcie-histb.o
> > >   obj-$(CONFIG_PCI_MESON) += pci-meson.o
> > > +obj-$(CONFIG_PCIE_TEGRA194) += pcie-tegra194.o
> > >   obj-$(CONFIG_PCIE_UNIPHIER) += pcie-uniphier.o
> > >   # The following drivers are for devices that use the generic ACPI
> > > diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
> > > new file mode 100644
> > > index 000000000000..4b3a1d4125b6
> > > --- /dev/null
> > > +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
> > > @@ -0,0 +1,1620 @@
> > > +// SPDX-License-Identifier: GPL-2.0+
> > > +/*
> > > + * PCIe host controller driver for Tegra194 SoC
> > > + *
> > > + * Copyright (C) 2019 NVIDIA Corporation.
> > > + *
> > > + * Author: Vidya Sagar <vidyas@nvidia.com>
> > > + */
> > > +
> > > +#include <linux/clk.h>
> > > +#include <linux/debugfs.h>
> > > +#include <linux/delay.h>
> > > +#include <linux/gpio.h>
> > > +#include <linux/interrupt.h>
> > > +#include <linux/iopoll.h>
> > > +#include <linux/kernel.h>
> > > +#include <linux/kfifo.h>
> > > +#include <linux/kthread.h>
> > > +#include <linux/module.h>
> > > +#include <linux/of.h>
> > > +#include <linux/of_device.h>
> > > +#include <linux/of_gpio.h>
> > > +#include <linux/of_irq.h>
> > > +#include <linux/of_pci.h>
> > > +#include <linux/pci.h>
> > > +#include <linux/pci-aspm.h>
> > > +#include <linux/phy/phy.h>
> > > +#include <linux/platform_device.h>
> > > +#include <linux/pm_runtime.h>
> > > +#include <linux/random.h>
> > > +#include <linux/reset.h>
> > > +#include <linux/resource.h>
> > > +#include <linux/types.h>
> > > +#include "pcie-designware.h"
> > > +#include <soc/tegra/bpmp.h>
> > > +#include <soc/tegra/bpmp-abi.h>
> > > +#include "../../pci.h"
> > > +
> > > +#define CTRL_5	5
> > 
> > There isn't really a need for this since you only use it once and the
> > CTRL_ prefix doesn't really add any contextual information in that case.
> > Might as well just hardcode that 5 in the one location.
> Ok.
> 
> > 
> > > +
> > > +#define APPL_PINMUX				0x0
> > > +#define APPL_PINMUX_PEX_RST			BIT(0)
> > > +#define APPL_PINMUX_CLKREQ_OVERRIDE_EN		BIT(2)
> > > +#define APPL_PINMUX_CLKREQ_OVERRIDE		BIT(3)
> > > +#define APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE_EN	BIT(4)
> > > +#define APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE	BIT(5)
> > > +#define APPL_PINMUX_CLKREQ_OUT_OVRD_EN		BIT(9)
> > > +#define APPL_PINMUX_CLKREQ_OUT_OVRD		BIT(10)
> > > +
> > > +#define APPL_CTRL				0x4
> > > +#define APPL_CTRL_SYS_PRE_DET_STATE		BIT(6)
> > > +#define APPL_CTRL_LTSSM_EN			BIT(7)
> > > +#define APPL_CTRL_HW_HOT_RST_EN			BIT(20)
> > > +#define APPL_CTRL_HW_HOT_RST_MODE_MASK		GENMASK(1, 0)
> > > +#define APPL_CTRL_HW_HOT_RST_MODE_SHIFT		22
> > > +#define APPL_CTRL_HW_HOT_RST_MODE_IMDT_RST	0x1
> > > +
> > > +#define APPL_INTR_EN_L0_0			0x8
> > > +#define APPL_INTR_EN_L0_0_LINK_STATE_INT_EN	BIT(0)
> > > +#define APPL_INTR_EN_L0_0_MSI_RCV_INT_EN	BIT(4)
> > > +#define APPL_INTR_EN_L0_0_INT_INT_EN		BIT(8)
> > > +#define APPL_INTR_EN_L0_0_CDM_REG_CHK_INT_EN	BIT(19)
> > > +#define APPL_INTR_EN_L0_0_SYS_INTR_EN		BIT(30)
> > > +#define APPL_INTR_EN_L0_0_SYS_MSI_INTR_EN	BIT(31)
> > > +
> > > +#define APPL_INTR_STATUS_L0			0xC
> > > +#define APPL_INTR_STATUS_L0_LINK_STATE_INT	BIT(0)
> > > +#define APPL_INTR_STATUS_L0_INT_INT		BIT(8)
> > > +#define APPL_INTR_STATUS_L0_CDM_REG_CHK_INT	BIT(18)
> > > +
> > > +#define APPL_INTR_EN_L1_0_0				0x1C
> > > +#define APPL_INTR_EN_L1_0_0_LINK_REQ_RST_NOT_INT_EN	BIT(1)
> > > +
> > > +#define APPL_INTR_STATUS_L1_0_0				0x20
> > > +#define APPL_INTR_STATUS_L1_0_0_LINK_REQ_RST_NOT_CHGED	BIT(1)
> > > +
> > > +#define APPL_INTR_STATUS_L1_1			0x2C
> > > +#define APPL_INTR_STATUS_L1_2			0x30
> > > +#define APPL_INTR_STATUS_L1_3			0x34
> > > +#define APPL_INTR_STATUS_L1_6			0x3C
> > > +#define APPL_INTR_STATUS_L1_7			0x40
> > > +
> > > +#define APPL_INTR_EN_L1_8_0			0x44
> > > +#define APPL_INTR_EN_L1_8_BW_MGT_INT_EN		BIT(2)
> > > +#define APPL_INTR_EN_L1_8_AUTO_BW_INT_EN	BIT(3)
> > > +#define APPL_INTR_EN_L1_8_INTX_EN		BIT(11)
> > > +#define APPL_INTR_EN_L1_8_AER_INT_EN		BIT(15)
> > > +
> > > +#define APPL_INTR_STATUS_L1_8_0			0x4C
> > > +#define APPL_INTR_STATUS_L1_8_0_EDMA_INT_MASK	GENMASK(11, 6)
> > > +#define APPL_INTR_STATUS_L1_8_0_BW_MGT_INT_STS	BIT(2)
> > > +#define APPL_INTR_STATUS_L1_8_0_AUTO_BW_INT_STS	BIT(3)
> > > +
> > > +#define APPL_INTR_STATUS_L1_9			0x54
> > > +#define APPL_INTR_STATUS_L1_10			0x58
> > > +#define APPL_INTR_STATUS_L1_11			0x64
> > > +#define APPL_INTR_STATUS_L1_13			0x74
> > > +#define APPL_INTR_STATUS_L1_14			0x78
> > > +#define APPL_INTR_STATUS_L1_15			0x7C
> > > +#define APPL_INTR_STATUS_L1_17			0x88
> > > +
> > > +#define APPL_INTR_EN_L1_18				0x90
> > > +#define APPL_INTR_EN_L1_18_CDM_REG_CHK_CMPLT		BIT(2)
> > > +#define APPL_INTR_EN_L1_18_CDM_REG_CHK_CMP_ERR		BIT(1)
> > > +#define APPL_INTR_EN_L1_18_CDM_REG_CHK_LOGIC_ERR	BIT(0)
> > > +
> > > +#define APPL_INTR_STATUS_L1_18				0x94
> > > +#define APPL_INTR_STATUS_L1_18_CDM_REG_CHK_CMPLT	BIT(2)
> > > +#define APPL_INTR_STATUS_L1_18_CDM_REG_CHK_CMP_ERR	BIT(1)
> > > +#define APPL_INTR_STATUS_L1_18_CDM_REG_CHK_LOGIC_ERR	BIT(0)
> > > +
> > > +#define APPL_MSI_CTRL_2				0xB0
> > > +
> > > +#define APPL_LTR_MSG_1				0xC4
> > > +#define LTR_MSG_REQ				BIT(15)
> > > +#define LTR_MST_NO_SNOOP_SHIFT			16
> > > +
> > > +#define APPL_LTR_MSG_2				0xC8
> > > +#define APPL_LTR_MSG_2_LTR_MSG_REQ_STATE	BIT(3)
> > > +
> > > +#define APPL_LINK_STATUS			0xCC
> > > +#define APPL_LINK_STATUS_RDLH_LINK_UP		BIT(0)
> > > +
> > > +#define APPL_DEBUG				0xD0
> > > +#define APPL_DEBUG_PM_LINKST_IN_L2_LAT		BIT(21)
> > > +#define APPL_DEBUG_PM_LINKST_IN_L0		0x11
> > > +#define APPL_DEBUG_LTSSM_STATE_MASK		GENMASK(8, 3)
> > > +#define APPL_DEBUG_LTSSM_STATE_SHIFT		3
> > > +#define LTSSM_STATE_PRE_DETECT			5
> > > +
> > > +#define APPL_RADM_STATUS			0xE4
> > > +#define APPL_PM_XMT_TURNOFF_STATE		BIT(0)
> > > +
> > > +#define APPL_DM_TYPE				0x100
> > > +#define APPL_DM_TYPE_MASK			GENMASK(3, 0)
> > > +#define APPL_DM_TYPE_RP				0x4
> > > +#define APPL_DM_TYPE_EP				0x0
> > > +
> > > +#define APPL_CFG_BASE_ADDR			0x104
> > > +#define APPL_CFG_BASE_ADDR_MASK			GENMASK(31, 12)
> > > +
> > > +#define APPL_CFG_IATU_DMA_BASE_ADDR		0x108
> > > +#define APPL_CFG_IATU_DMA_BASE_ADDR_MASK	GENMASK(31, 18)
> > > +
> > > +#define APPL_CFG_MISC				0x110
> > > +#define APPL_CFG_MISC_SLV_EP_MODE		BIT(14)
> > > +#define APPL_CFG_MISC_ARCACHE_MASK		GENMASK(13, 10)
> > > +#define APPL_CFG_MISC_ARCACHE_SHIFT		10
> > > +#define APPL_CFG_MISC_ARCACHE_VAL		3
> > > +
> > > +#define APPL_CFG_SLCG_OVERRIDE			0x114
> > > +#define APPL_CFG_SLCG_OVERRIDE_SLCG_EN_MASTER	BIT(0)
> > > +
> > > +#define APPL_CAR_RESET_OVRD				0x12C
> > > +#define APPL_CAR_RESET_OVRD_CYA_OVERRIDE_CORE_RST_N	BIT(0)
> > > +
> > > +#define IO_BASE_IO_DECODE				BIT(0)
> > > +#define IO_BASE_IO_DECODE_BIT8				BIT(8)
> > > +
> > > +#define CFG_PREF_MEM_LIMIT_BASE_MEM_DECODE		BIT(0)
> > > +#define CFG_PREF_MEM_LIMIT_BASE_MEM_LIMIT_DECODE	BIT(16)
> > > +
> > > +#define CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF	0x718
> > > +#define CFG_TIMER_CTRL_ACK_NAK_SHIFT	(19)
> > > +
> > > +#define EVENT_COUNTER_ALL_CLEAR		0x3
> > > +#define EVENT_COUNTER_ENABLE_ALL	0x7
> > > +#define EVENT_COUNTER_ENABLE_SHIFT	2
> > > +#define EVENT_COUNTER_EVENT_SEL_MASK	GENMASK(7, 0)
> > > +#define EVENT_COUNTER_EVENT_SEL_SHIFT	16
> > > +#define EVENT_COUNTER_EVENT_Tx_L0S	0x2
> > > +#define EVENT_COUNTER_EVENT_Rx_L0S	0x3
> > > +#define EVENT_COUNTER_EVENT_L1		0x5
> > > +#define EVENT_COUNTER_EVENT_L1_1	0x7
> > > +#define EVENT_COUNTER_EVENT_L1_2	0x8
> > > +#define EVENT_COUNTER_GROUP_SEL_SHIFT	24
> > > +#define EVENT_COUNTER_GROUP_5		0x5
> > > +
> > > +#define PORT_LOGIC_ACK_F_ASPM_CTRL			0x70C
> > > +#define ENTER_ASPM					BIT(30)
> > > +#define L0S_ENTRANCE_LAT_SHIFT				24
> > > +#define L0S_ENTRANCE_LAT_MASK				GENMASK(26, 24)
> > > +#define L1_ENTRANCE_LAT_SHIFT				27
> > > +#define L1_ENTRANCE_LAT_MASK				GENMASK(29, 27)
> > > +#define N_FTS_SHIFT					8
> > > +#define N_FTS_MASK					GENMASK(7, 0)
> > > +#define N_FTS_VAL					52
> > > +
> > > +#define PORT_LOGIC_GEN2_CTRL				0x80C
> > > +#define PORT_LOGIC_GEN2_CTRL_DIRECT_SPEED_CHANGE	BIT(17)
> > > +#define FTS_MASK					GENMASK(7, 0)
> > > +#define FTS_VAL						52
> > > +
> > > +#define PORT_LOGIC_MSI_CTRL_INT_0_EN		0x828
> > > +
> > > +#define GEN3_EQ_CONTROL_OFF			0x8a8
> > > +#define GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_SHIFT	8
> > > +#define GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK	GENMASK(23, 8)
> > > +#define GEN3_EQ_CONTROL_OFF_FB_MODE_MASK	GENMASK(3, 0)
> > > +
> > > +#define GEN3_RELATED_OFF			0x890
> > > +#define GEN3_RELATED_OFF_GEN3_ZRXDC_NONCOMPL	BIT(0)
> > > +#define GEN3_RELATED_OFF_GEN3_EQ_DISABLE	BIT(16)
> > > +#define GEN3_RELATED_OFF_RATE_SHADOW_SEL_SHIFT	24
> > > +#define GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK	GENMASK(25, 24)
> > > +
> > > +#define PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT	0x8D0
> > > +#define AMBA_ERROR_RESPONSE_CRS_SHIFT		3
> > > +#define AMBA_ERROR_RESPONSE_CRS_MASK		GENMASK(1, 0)
> > > +#define AMBA_ERROR_RESPONSE_CRS_OKAY		0
> > > +#define AMBA_ERROR_RESPONSE_CRS_OKAY_FFFFFFFF	1
> > > +#define AMBA_ERROR_RESPONSE_CRS_OKAY_FFFF0001	2
> > > +
> > > +#define PORT_LOGIC_MSIX_DOORBELL			0x948
> > > +
> > > +#define CAP_SPCIE_CAP_OFF			0x154
> > > +#define CAP_SPCIE_CAP_OFF_DSP_TX_PRESET0_MASK	GENMASK(3, 0)
> > > +#define CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_MASK	GENMASK(11, 8)
> > > +#define CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_SHIFT	8
> > > +
> > > +#define PL16G_CAP_OFF_DSP_16G_TX_PRESET_MASK	GENMASK(3, 0)
> > > +#define PL16G_CAP_OFF_USP_16G_TX_PRESET_MASK	GENMASK(7, 4)
> > > +#define PL16G_CAP_OFF_USP_16G_TX_PRESET_SHIFT	4
> > > +
> > > +#define PME_ACK_TIMEOUT 10000
> > > +
> > > +#define LTSSM_TIMEOUT 50000	/* 50ms */
> > > +
> > > +#define GEN3_GEN4_EQ_PRESET_INIT	5
> > > +
> > > +#define GEN1_CORE_CLK_FREQ	62500000
> > > +#define GEN2_CORE_CLK_FREQ	125000000
> > > +#define GEN3_CORE_CLK_FREQ	250000000
> > > +#define GEN4_CORE_CLK_FREQ	500000000
> > > +
> > > +static const unsigned int pcie_gen_freq[] = {
> > > +	GEN1_CORE_CLK_FREQ,
> > > +	GEN2_CORE_CLK_FREQ,
> > > +	GEN3_CORE_CLK_FREQ,
> > > +	GEN4_CORE_CLK_FREQ
> > > +};
> > > +
> > > +static const u32 event_cntr_ctrl_offset[] = {
> > > +	0x1d8,
> > > +	0x1a8,
> > > +	0x1a8,
> > > +	0x1a8,
> > > +	0x1c4,
> > > +	0x1d8
> > > +};
> > > +
> > > +static const u32 event_cntr_data_offset[] = {
> > > +	0x1dc,
> > > +	0x1ac,
> > > +	0x1ac,
> > > +	0x1ac,
> > > +	0x1c8,
> > > +	0x1dc
> > > +};
> > > +
> > > +struct tegra_pcie_dw {
> > > +	struct device *dev;
> > > +	struct resource *appl_res;
> > > +	struct resource *dbi_res;
> > > +	struct resource *atu_dma_res;
> > > +	void __iomem *appl_base;
> > > +	struct clk *core_clk;
> > > +	struct reset_control *core_apb_rst;
> > > +	struct reset_control *core_rst;
> > > +	struct dw_pcie pci;
> > > +	enum dw_pcie_device_mode mode;
> > > +	struct tegra_bpmp *bpmp;
> > > +
> > > +	bool supports_clkreq;
> > > +	u8 init_link_width;
> > > +	bool link_state;
> > > +	u32 msi_ctrl_int;
> > > +	u32 num_lanes;
> > > +	u32 max_speed;
> > > +	u32 cid;
> > > +	bool update_fc_fixup;
> > > +	u32 cfg_link_cap_l1sub;
> > > +	u32 pcie_cap_base;
> > > +	u32 aspm_cmrt;
> > > +	u32 aspm_pwr_on_t;
> > > +	u32 aspm_l0s_enter_lat;
> > > +
> > > +	struct regulator *pex_ctl_supply;
> > > +
> > > +	u32 phy_count;
> > 
> > This doesn't need to be a sized type. unsigned int would do just fine.
> Ok.
> 
> > 
> > > +	struct phy **phys;
> > > +
> > > +	struct dentry *debugfs;
> > > +};
> > > +
> > > +static inline struct tegra_pcie_dw *to_tegra_pcie(struct dw_pcie *pci)
> > > +{
> > > +	return container_of(pci, struct tegra_pcie_dw, pci);
> > > +}
> > > +
> > > +struct tegra_pcie_soc {
> > > +	enum dw_pcie_device_mode mode;
> > > +};
> > > +
> > > +static void apply_bad_link_workaround(struct pcie_port *pp)
> > > +{
> > > +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> > > +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> > > +	u32 current_link_width;
> > > +	u16 val;
> > > +
> > > +	/*
> > > +	 * NOTE:- Since this scenario is uncommon and link as such is not
> > > +	 * stable anyway, not waiting to confirm if link is really
> > > +	 * transitioning to Gen-2 speed
> > > +	 */
> > > +	val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
> > > +	if (val & PCI_EXP_LNKSTA_LBMS) {
> > > +		current_link_width = (val & PCI_EXP_LNKSTA_NLW) >>
> > > +				     PCI_EXP_LNKSTA_NLW_SHIFT;
> > > +		if (pcie->init_link_width > current_link_width) {
> > > +			dev_warn(pci->dev, "PCIe link is bad, width reduced\n");
> > > +			val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
> > > +						PCI_EXP_LNKCTL2);
> > > +			val &= ~PCI_EXP_LNKCTL2_TLS;
> > > +			val |= PCI_EXP_LNKCTL2_TLS_2_5GT;
> > > +			dw_pcie_writew_dbi(pci, pcie->pcie_cap_base +
> > > +					   PCI_EXP_LNKCTL2, val);
> > > +
> > > +			val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
> > > +						PCI_EXP_LNKCTL);
> > > +			val |= PCI_EXP_LNKCTL_RL;
> > > +			dw_pcie_writew_dbi(pci, pcie->pcie_cap_base +
> > > +					   PCI_EXP_LNKCTL, val);
> > > +		}
> > > +	}
> > > +}
> > > +
> > > +static irqreturn_t tegra_pcie_rp_irq_handler(struct tegra_pcie_dw *pcie)
> > > +{
> > > +	struct dw_pcie *pci = &pcie->pci;
> > > +	struct pcie_port *pp = &pci->pp;
> > > +	u32 val, tmp;
> > > +	u16 val_w;
> > > +
> > > +	val = readl(pcie->appl_base + APPL_INTR_STATUS_L0);
> > > +	if (val & APPL_INTR_STATUS_L0_LINK_STATE_INT) {
> > > +		val = readl(pcie->appl_base + APPL_INTR_STATUS_L1_0_0);
> > > +		if (val & APPL_INTR_STATUS_L1_0_0_LINK_REQ_RST_NOT_CHGED) {
> > > +			writel(val, pcie->appl_base + APPL_INTR_STATUS_L1_0_0);
> > > +
> > > +			/* SBR & Surprise Link Down WAR */
> > > +			val = readl(pcie->appl_base + APPL_CAR_RESET_OVRD);
> > > +			val &= ~APPL_CAR_RESET_OVRD_CYA_OVERRIDE_CORE_RST_N;
> > > +			writel(val, pcie->appl_base + APPL_CAR_RESET_OVRD);
> > > +			udelay(1);
> > > +			val = readl(pcie->appl_base + APPL_CAR_RESET_OVRD);
> > > +			val |= APPL_CAR_RESET_OVRD_CYA_OVERRIDE_CORE_RST_N;
> > > +			writel(val, pcie->appl_base + APPL_CAR_RESET_OVRD);
> > > +
> > > +			val = dw_pcie_readl_dbi(pci, PORT_LOGIC_GEN2_CTRL);
> > > +			val |= PORT_LOGIC_GEN2_CTRL_DIRECT_SPEED_CHANGE;
> > > +			dw_pcie_writel_dbi(pci, PORT_LOGIC_GEN2_CTRL, val);
> > > +		}
> > > +	}
> > > +	if (val & APPL_INTR_STATUS_L0_INT_INT) {
> > 
> > I think you could use a blank line here (and elsewhere) to separate
> > blocks of code for better readability.
> Done.
> 
> > 
> > > +		val = readl(pcie->appl_base + APPL_INTR_STATUS_L1_8_0);
> > > +		if (val & APPL_INTR_STATUS_L1_8_0_AUTO_BW_INT_STS) {
> > > +			writel(APPL_INTR_STATUS_L1_8_0_AUTO_BW_INT_STS,
> > > +			       pcie->appl_base + APPL_INTR_STATUS_L1_8_0);
> > > +			apply_bad_link_workaround(pp);
> > > +		}
> > > +		if (val & APPL_INTR_STATUS_L1_8_0_BW_MGT_INT_STS) {
> > > +			writel(APPL_INTR_STATUS_L1_8_0_BW_MGT_INT_STS,
> > > +			       pcie->appl_base + APPL_INTR_STATUS_L1_8_0);
> > > +
> > > +			val_w = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
> > > +						  PCI_EXP_LNKSTA);
> > > +			dev_dbg(pci->dev, "Link Speed : Gen-%u\n", val_w &
> > > +				PCI_EXP_LNKSTA_CLS);
> > > +		}
> > > +	}
> > > +	val = readl(pcie->appl_base + APPL_INTR_STATUS_L0);
> > > +	if (val & APPL_INTR_STATUS_L0_CDM_REG_CHK_INT) {
> > > +		val = readl(pcie->appl_base + APPL_INTR_STATUS_L1_18);
> > > +		tmp = dw_pcie_readl_dbi(pci, PCIE_PL_CHK_REG_CONTROL_STATUS);
> > > +		if (val & APPL_INTR_STATUS_L1_18_CDM_REG_CHK_CMPLT) {
> > > +			dev_info(pci->dev, "CDM check complete\n");
> > > +			tmp |= PCIE_PL_CHK_REG_CHK_REG_COMPLETE;
> > > +		}
> > > +		if (val & APPL_INTR_STATUS_L1_18_CDM_REG_CHK_CMP_ERR) {
> > > +			dev_err(pci->dev, "CDM comparison mismatch\n");
> > > +			tmp |= PCIE_PL_CHK_REG_CHK_REG_COMPARISON_ERROR;
> > > +		}
> > > +		if (val & APPL_INTR_STATUS_L1_18_CDM_REG_CHK_LOGIC_ERR) {
> > > +			dev_err(pci->dev, "CDM Logic error\n");
> > > +			tmp |= PCIE_PL_CHK_REG_CHK_REG_LOGIC_ERROR;
> > > +		}
> > > +		dw_pcie_writel_dbi(pci, PCIE_PL_CHK_REG_CONTROL_STATUS, tmp);
> > > +		tmp = dw_pcie_readl_dbi(pci, PCIE_PL_CHK_REG_ERR_ADDR);
> > > +		dev_err(pci->dev, "CDM Error Address Offset = 0x%08X\n", tmp);
> > > +	}
> > > +
> > > +	return IRQ_HANDLED;
> > > +}
> > > +
> > > +static irqreturn_t tegra_pcie_irq_handler(int irq, void *arg)
> > > +{
> > > +	struct tegra_pcie_dw *pcie = (struct tegra_pcie_dw *)arg;
> > 
> > No need for this explicit cast.
> Ok.
> 
> > 
> > > +
> > > +	if (pcie->mode == DW_PCIE_RC_TYPE)
> > > +		return tegra_pcie_rp_irq_handler(pcie);
> > > +
> > > +	return IRQ_NONE;
> > > +}
> > > +
> > > +static int tegra_pcie_dw_rd_own_conf(struct pcie_port *pp, int where, int size,
> > > +				     u32 *val)
> > > +{
> > > +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> > > +
> > > +	/*
> > > +	 * This is an endpoint mode specific register happen to appear even
> > > +	 * when controller is operating in root port mode and system hangs
> > > +	 * when it is accessed with link being in ASPM-L1 state.
> > > +	 * So skip accessing it altogether
> > > +	 */
> > > +	if (where == PORT_LOGIC_MSIX_DOORBELL) {
> > > +		*val = 0x00000000;
> > > +		return PCIBIOS_SUCCESSFUL;
> > > +	}
> > > +
> > > +	return dw_pcie_read(pci->dbi_base + where, size, val);
> > > +}
> > > +
> > > +static int tegra_pcie_dw_wr_own_conf(struct pcie_port *pp, int where, int size,
> > > +				     u32 val)
> > > +{
> > > +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> > > +
> > > +	/*
> > > +	 * This is an endpoint mode specific register happen to appear even
> > > +	 * when controller is operating in root port mode and system hangs
> > > +	 * when it is accessed with link being in ASPM-L1 state.
> > > +	 * So skip accessing it altogether
> > > +	 */
> > > +	if (where == PORT_LOGIC_MSIX_DOORBELL)
> > > +		return PCIBIOS_SUCCESSFUL;
> > > +
> > > +	return dw_pcie_write(pci->dbi_base + where, size, val);
> > > +}
> > > +
> > > +#if defined(CONFIG_PCIEASPM)
> > > +static void disable_aspm_l11(struct tegra_pcie_dw *pcie)
> > > +{
> > > +	u32 val;
> > > +
> > > +	val = dw_pcie_readl_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub);
> > > +	val &= ~PCI_L1SS_CAP_ASPM_L1_1;
> > > +	dw_pcie_writel_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub, val);
> > > +}
> > > +
> > > +static void disable_aspm_l12(struct tegra_pcie_dw *pcie)
> > > +{
> > > +	u32 val;
> > > +
> > > +	val = dw_pcie_readl_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub);
> > > +	val &= ~PCI_L1SS_CAP_ASPM_L1_2;
> > > +	dw_pcie_writel_dbi(&pcie->pci, pcie->cfg_link_cap_l1sub, val);
> > > +}
> > > +
> > > +static inline u32 event_counter_prog(struct tegra_pcie_dw *pcie, u32 event)
> > > +{
> > > +	u32 val;
> > > +
> > > +	val = dw_pcie_readl_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid]);
> > > +	val &= ~(EVENT_COUNTER_EVENT_SEL_MASK << EVENT_COUNTER_EVENT_SEL_SHIFT);
> > > +	val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
> > > +	val |= event << EVENT_COUNTER_EVENT_SEL_SHIFT;
> > > +	val |= EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
> > > +	dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid], val);
> > > +	val = dw_pcie_readl_dbi(&pcie->pci, event_cntr_data_offset[pcie->cid]);
> > > +	return val;
> > > +}
> > > +
> > > +static int aspm_state_cnt(struct seq_file *s, void *data)
> > > +{
> > > +	struct tegra_pcie_dw *pcie = (struct tegra_pcie_dw *)
> > > +				     dev_get_drvdata(s->private);
> > > +	u32 val;
> > > +
> > > +	seq_printf(s, "Tx L0s entry count : %u\n",
> > > +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_Tx_L0S));
> > > +
> > > +	seq_printf(s, "Rx L0s entry count : %u\n",
> > > +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_Rx_L0S));
> > > +
> > > +	seq_printf(s, "Link L1 entry count : %u\n",
> > > +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1));
> > > +
> > > +	seq_printf(s, "Link L1.1 entry count : %u\n",
> > > +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1_1));
> > > +
> > > +	seq_printf(s, "Link L1.2 entry count : %u\n",
> > > +		   event_counter_prog(pcie, EVENT_COUNTER_EVENT_L1_2));
> > > +
> > > +	/* Clear all counters */
> > > +	dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid],
> > > +			   EVENT_COUNTER_ALL_CLEAR);
> > > +
> > > +	/* Re-enable counting */
> > > +	val = EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
> > > +	val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
> > > +	dw_pcie_writel_dbi(&pcie->pci, event_cntr_ctrl_offset[pcie->cid], val);
> > > +
> > > +	return 0;
> > > +}
> > > +#endif
> > > +
> > > +static int init_debugfs(struct tegra_pcie_dw *pcie)
> > > +{
> > > +#if defined(CONFIG_PCIEASPM)
> > > +	struct dentry *d;
> > > +
> > > +	d = debugfs_create_devm_seqfile(pcie->dev, "aspm_state_cnt",
> > > +					pcie->debugfs, aspm_state_cnt);
> > > +	if (IS_ERR_OR_NULL(d))
> > > +		dev_err(pcie->dev,
> > > +			"Failed to create debugfs file \"aspm_state_cnt\"\n");
> > > +#endif
> > > +	return 0;
> > > +}
> > > +
> > > +static void tegra_pcie_enable_system_interrupts(struct pcie_port *pp)
> > > +{
> > > +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> > > +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> > > +	u32 val;
> > > +	u16 val_w;
> > > +
> > > +	val = readl(pcie->appl_base + APPL_INTR_EN_L0_0);
> > > +	val |= APPL_INTR_EN_L0_0_LINK_STATE_INT_EN;
> > > +	writel(val, pcie->appl_base + APPL_INTR_EN_L0_0);
> > > +
> > > +	val = readl(pcie->appl_base + APPL_INTR_EN_L1_0_0);
> > > +	val |= APPL_INTR_EN_L1_0_0_LINK_REQ_RST_NOT_INT_EN;
> > > +	writel(val, pcie->appl_base + APPL_INTR_EN_L1_0_0);
> > > +
> > > +	if (of_property_read_bool(pci->dev->of_node, "cdm-check")) {
> > 
> > This doesn't match the DT bindings if I remember correctly. It might
> > also be worth reading this at *_dt_parse() time and storing the result
> > in a field of struct tegra_pcie_dw.
> Since this is the only place where I'm checking it, I thought, I would parse
> DT directly. But, anyway, I'll have a field to store this info.

This isn't so much about caching the result to avoid scanning the DT.
I'm more concerned about having the code split up in such a way to do
logically related things in the same place. So if you parse the DT in
one place, might as well parse all DT in that place. That way the code
becomes easier to read because locations like this don't stand out so
much (i.e. there are no other OF calls anywhere near this, so it looks
out of place).

> 
> > 
> > > +		val = readl(pcie->appl_base + APPL_INTR_EN_L0_0);
> > > +		val |= APPL_INTR_EN_L0_0_CDM_REG_CHK_INT_EN;
> > > +		writel(val, pcie->appl_base + APPL_INTR_EN_L0_0);
> > > +
> > > +		val = readl(pcie->appl_base + APPL_INTR_EN_L1_18);
> > > +		val |= APPL_INTR_EN_L1_18_CDM_REG_CHK_CMP_ERR;
> > > +		val |= APPL_INTR_EN_L1_18_CDM_REG_CHK_LOGIC_ERR;
> > > +		writel(val, pcie->appl_base + APPL_INTR_EN_L1_18);
> > > +	}
> > > +
> > > +	val_w = dw_pcie_readw_dbi(&pcie->pci, pcie->pcie_cap_base +
> > > +				  PCI_EXP_LNKSTA);
> > > +	pcie->init_link_width = (val_w & PCI_EXP_LNKSTA_NLW) >>
> > > +				PCI_EXP_LNKSTA_NLW_SHIFT;
> > > +
> > > +	val_w = dw_pcie_readw_dbi(&pcie->pci, pcie->pcie_cap_base +
> > > +				  PCI_EXP_LNKCTL);
> > > +	val_w |= PCI_EXP_LNKCTL_LBMIE;
> > > +	dw_pcie_writew_dbi(&pcie->pci, pcie->pcie_cap_base + PCI_EXP_LNKCTL,
> > > +			   val_w);
> > > +}
> > > +
> > > +static void tegra_pcie_enable_legacy_interrupts(struct pcie_port *pp)
> > > +{
> > > +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> > > +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> > > +	u32 val;
> > > +
> > > +	/* Enable legacy interrupt generation */
> > > +	val = readl(pcie->appl_base + APPL_INTR_EN_L0_0);
> > > +	val |= APPL_INTR_EN_L0_0_SYS_INTR_EN;
> > > +	val |= APPL_INTR_EN_L0_0_INT_INT_EN;
> > > +	writel(val, pcie->appl_base + APPL_INTR_EN_L0_0);
> > > +
> > > +	val = readl(pcie->appl_base + APPL_INTR_EN_L1_8_0);
> > > +	val |= APPL_INTR_EN_L1_8_INTX_EN;
> > > +	val |= APPL_INTR_EN_L1_8_AUTO_BW_INT_EN;
> > > +	val |= APPL_INTR_EN_L1_8_BW_MGT_INT_EN;
> > > +	if (IS_ENABLED(CONFIG_PCIEAER))
> > > +		val |= APPL_INTR_EN_L1_8_AER_INT_EN;
> > > +	writel(val, pcie->appl_base + APPL_INTR_EN_L1_8_0);
> > > +}
> > > +
> > > +static void tegra_pcie_enable_msi_interrupts(struct pcie_port *pp)
> > > +{
> > > +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> > > +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> > > +	u32 val;
> > > +
> > > +	dw_pcie_msi_init(pp);
> > > +
> > > +	/* Enable MSI interrupt generation */
> > > +	val = readl(pcie->appl_base + APPL_INTR_EN_L0_0);
> > > +	val |= APPL_INTR_EN_L0_0_SYS_MSI_INTR_EN;
> > > +	val |= APPL_INTR_EN_L0_0_MSI_RCV_INT_EN;
> > > +	writel(val, pcie->appl_base + APPL_INTR_EN_L0_0);
> > > +}
> > > +
> > > +static void tegra_pcie_enable_interrupts(struct pcie_port *pp)
> > > +{
> > > +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> > > +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> > > +
> > > +	/* Clear interrupt statuses before enabling interrupts */
> > > +	writel(0xFFFFFFFF, pcie->appl_base + APPL_INTR_STATUS_L0);
> > > +	writel(0xFFFFFFFF, pcie->appl_base + APPL_INTR_STATUS_L1_0_0);
> > > +	writel(0xFFFFFFFF, pcie->appl_base + APPL_INTR_STATUS_L1_1);
> > > +	writel(0xFFFFFFFF, pcie->appl_base + APPL_INTR_STATUS_L1_2);
> > > +	writel(0xFFFFFFFF, pcie->appl_base + APPL_INTR_STATUS_L1_3);
> > > +	writel(0xFFFFFFFF, pcie->appl_base + APPL_INTR_STATUS_L1_6);
> > > +	writel(0xFFFFFFFF, pcie->appl_base + APPL_INTR_STATUS_L1_7);
> > > +	writel(0xFFFFFFFF, pcie->appl_base + APPL_INTR_STATUS_L1_8_0);
> > > +	writel(0xFFFFFFFF, pcie->appl_base + APPL_INTR_STATUS_L1_9);
> > > +	writel(0xFFFFFFFF, pcie->appl_base + APPL_INTR_STATUS_L1_10);
> > > +	writel(0xFFFFFFFF, pcie->appl_base + APPL_INTR_STATUS_L1_11);
> > > +	writel(0xFFFFFFFF, pcie->appl_base + APPL_INTR_STATUS_L1_13);
> > > +	writel(0xFFFFFFFF, pcie->appl_base + APPL_INTR_STATUS_L1_14);
> > > +	writel(0xFFFFFFFF, pcie->appl_base + APPL_INTR_STATUS_L1_15);
> > > +	writel(0xFFFFFFFF, pcie->appl_base + APPL_INTR_STATUS_L1_17);
> > > +
> > > +	tegra_pcie_enable_system_interrupts(pp);
> > > +	tegra_pcie_enable_legacy_interrupts(pp);
> > > +	if (IS_ENABLED(CONFIG_PCI_MSI))
> > > +		tegra_pcie_enable_msi_interrupts(pp);
> > > +}
> > > +
> > > +static void config_gen3_gen4_eq_presets(struct tegra_pcie_dw *pcie)
> > > +{
> > > +	struct dw_pcie *pci = &pcie->pci;
> > > +	u32 val, offset, i;
> > > +
> > > +	/* Program init preset */
> > > +	for (i = 0; i < pcie->num_lanes; i++) {
> > > +		dw_pcie_read(pci->dbi_base + CAP_SPCIE_CAP_OFF
> > > +				 + (i * 2), 2, &val);
> > > +		val &= ~CAP_SPCIE_CAP_OFF_DSP_TX_PRESET0_MASK;
> > > +		val |= GEN3_GEN4_EQ_PRESET_INIT;
> > > +		val &= ~CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_MASK;
> > > +		val |= (GEN3_GEN4_EQ_PRESET_INIT <<
> > > +			   CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_SHIFT);
> > > +		dw_pcie_write(pci->dbi_base + CAP_SPCIE_CAP_OFF
> > > +				 + (i * 2), 2, val);
> > > +
> > > +		offset = dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_PL) +
> > > +				PCI_PL_16GT_LE_CTRL;
> > > +		dw_pcie_read(pci->dbi_base + offset + i, 1, &val);
> > > +		val &= ~PL16G_CAP_OFF_DSP_16G_TX_PRESET_MASK;
> > > +		val |= GEN3_GEN4_EQ_PRESET_INIT;
> > > +		val &= ~PL16G_CAP_OFF_USP_16G_TX_PRESET_MASK;
> > > +		val |= (GEN3_GEN4_EQ_PRESET_INIT <<
> > > +			PL16G_CAP_OFF_USP_16G_TX_PRESET_SHIFT);
> > > +		dw_pcie_write(pci->dbi_base + offset + i, 1, val);
> > > +	}
> > > +
> > > +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
> > > +	val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
> > > +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
> > > +
> > > +	val = dw_pcie_readl_dbi(pci, GEN3_EQ_CONTROL_OFF);
> > > +	val &= ~GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK;
> > > +	val |= (0x3ff << GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_SHIFT);
> > > +	val &= ~GEN3_EQ_CONTROL_OFF_FB_MODE_MASK;
> > > +	dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, val);
> > > +
> > > +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
> > > +	val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
> > > +	val |= (0x1 << GEN3_RELATED_OFF_RATE_SHADOW_SEL_SHIFT);
> > > +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
> > > +
> > > +	val = dw_pcie_readl_dbi(pci, GEN3_EQ_CONTROL_OFF);
> > > +	val &= ~GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_MASK;
> > > +	val |= (0x360 << GEN3_EQ_CONTROL_OFF_PSET_REQ_VEC_SHIFT);
> > > +	val &= ~GEN3_EQ_CONTROL_OFF_FB_MODE_MASK;
> > > +	dw_pcie_writel_dbi(pci, GEN3_EQ_CONTROL_OFF, val);
> > > +
> > > +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
> > > +	val &= ~GEN3_RELATED_OFF_RATE_SHADOW_SEL_MASK;
> > > +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
> > > +}
> > > +
> > > +static int tegra_pcie_dw_host_init(struct pcie_port *pp)
> > > +{
> > > +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> > > +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> > > +	u32 val, tmp, offset, speed;
> > > +	int count;
> > 
> > Can be unsigned int.
> Done.
> 
> > 
> > > +	u16 val_w;
> > > +
> > > +core_init:
> > > +	count = 200;
> > > +#if defined(CONFIG_PCIEASPM)
> > > +	offset = dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_L1SS);
> > > +	pcie->cfg_link_cap_l1sub = offset + PCI_L1SS_CAP;
> > > +#endif
> > > +	val = dw_pcie_readl_dbi(pci, PCI_IO_BASE);
> > > +	val &= ~(IO_BASE_IO_DECODE | IO_BASE_IO_DECODE_BIT8);
> > > +	dw_pcie_writel_dbi(pci, PCI_IO_BASE, val);
> > > +
> > > +	val = dw_pcie_readl_dbi(pci, PCI_PREF_MEMORY_BASE);
> > > +	val |= CFG_PREF_MEM_LIMIT_BASE_MEM_DECODE;
> > > +	val |= CFG_PREF_MEM_LIMIT_BASE_MEM_LIMIT_DECODE;
> > > +	dw_pcie_writel_dbi(pci, PCI_PREF_MEMORY_BASE, val);
> > > +
> > > +	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 0);
> > > +
> > > +	/* Configure FTS */
> > > +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL);
> > > +	val &= ~(N_FTS_MASK << N_FTS_SHIFT);
> > > +	val |= N_FTS_VAL << N_FTS_SHIFT;
> > > +	dw_pcie_writel_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL, val);
> > > +
> > > +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_GEN2_CTRL);
> > > +	val &= ~FTS_MASK;
> > > +	val |= FTS_VAL;
> > > +	dw_pcie_writel_dbi(pci, PORT_LOGIC_GEN2_CTRL, val);
> > > +
> > > +	/* Enable as 0xFFFF0001 response for CRS */
> > > +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT);
> > > +	val &= ~(AMBA_ERROR_RESPONSE_CRS_MASK << AMBA_ERROR_RESPONSE_CRS_SHIFT);
> > > +	val |= (AMBA_ERROR_RESPONSE_CRS_OKAY_FFFF0001 <<
> > > +		AMBA_ERROR_RESPONSE_CRS_SHIFT);
> > > +	dw_pcie_writel_dbi(pci, PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT, val);
> > > +
> > > +	/* Configure Max Speed from DT */
> > > +	if (pcie->max_speed && pcie->max_speed != -EINVAL) {
> > > +		val = dw_pcie_readl_dbi(pci, pcie->pcie_cap_base +
> > > +					PCI_EXP_LNKCAP);
> > > +		val &= ~PCI_EXP_LNKCAP_SLS;
> > > +		val |= pcie->max_speed;
> > > +		dw_pcie_writel_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP,
> > > +				   val);
> > > +	}
> > > +
> > > +	/* Configure Max lane width from DT */
> > > +	val = dw_pcie_readl_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP);
> > > +	val &= ~PCI_EXP_LNKCAP_MLW;
> > > +	val |= (pcie->num_lanes << PCI_EXP_LNKSTA_NLW_SHIFT);
> > > +	dw_pcie_writel_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKCAP, val);
> > > +
> > > +	config_gen3_gen4_eq_presets(pcie);
> > > +
> > > +#if defined(CONFIG_PCIEASPM)
> > > +	/* Enable ASPM counters */
> > > +	val = EVENT_COUNTER_ENABLE_ALL << EVENT_COUNTER_ENABLE_SHIFT;
> > > +	val |= EVENT_COUNTER_GROUP_5 << EVENT_COUNTER_GROUP_SEL_SHIFT;
> > > +	dw_pcie_writel_dbi(pci, event_cntr_ctrl_offset[pcie->cid], val);
> > > +
> > > +	/* Program T_cmrt and T_pwr_on values */
> > > +	val = dw_pcie_readl_dbi(pci, pcie->cfg_link_cap_l1sub);
> > > +	val &= ~(PCI_L1SS_CAP_CM_RESTORE_TIME | PCI_L1SS_CAP_P_PWR_ON_VALUE);
> > > +	val |= (pcie->aspm_cmrt << 8);
> > > +	val |= (pcie->aspm_pwr_on_t << 19);
> > > +	dw_pcie_writel_dbi(pci, pcie->cfg_link_cap_l1sub, val);
> > > +
> > > +	/* Program L0s and L1 entrance latencies */
> > > +	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL);
> > > +	val &= ~L0S_ENTRANCE_LAT_MASK;
> > > +	val |= (pcie->aspm_l0s_enter_lat << L0S_ENTRANCE_LAT_SHIFT);
> > > +	val |= ENTER_ASPM;
> > > +	dw_pcie_writel_dbi(pci, PORT_LOGIC_ACK_F_ASPM_CTRL, val);
> > > +#endif
> > > +	val = dw_pcie_readl_dbi(pci, GEN3_RELATED_OFF);
> > > +	val &= ~GEN3_RELATED_OFF_GEN3_ZRXDC_NONCOMPL;
> > > +	dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
> > > +
> > > +	if (pcie->update_fc_fixup) {
> > > +		val = dw_pcie_readl_dbi(pci, CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF);
> > > +		val |= 0x1 << CFG_TIMER_CTRL_ACK_NAK_SHIFT;
> > > +		dw_pcie_writel_dbi(pci, CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF, val);
> > > +	}
> > > +
> > > +	dw_pcie_setup_rc(pp);
> > > +
> > > +	clk_set_rate(pcie->core_clk, GEN4_CORE_CLK_FREQ);
> > > +
> > > +	/* Assert RST */
> > > +	val = readl(pcie->appl_base + APPL_PINMUX);
> > > +	val &= ~APPL_PINMUX_PEX_RST;
> > > +	writel(val, pcie->appl_base + APPL_PINMUX);
> > > +
> > > +	usleep_range(100, 200);
> > > +
> > > +	/* Enable LTSSM */
> > > +	val = readl(pcie->appl_base + APPL_CTRL);
> > > +	val |= APPL_CTRL_LTSSM_EN;
> > > +	writel(val, pcie->appl_base + APPL_CTRL);
> > > +
> > > +	/* De-assert RST */
> > > +	val = readl(pcie->appl_base + APPL_PINMUX);
> > > +	val |= APPL_PINMUX_PEX_RST;
> > > +	writel(val, pcie->appl_base + APPL_PINMUX);
> > > +
> > > +	msleep(100);
> > > +
> > > +	val_w = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
> > > +	while (!(val_w & PCI_EXP_LNKSTA_DLLLA)) {
> > > +		if (count) {
> > > +			dev_dbg(pci->dev, "Waiting for link up\n");
> > > +			usleep_range(1000, 2000);
> > > +			val_w = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
> > > +						  PCI_EXP_LNKSTA);
> > > +			count--;
> > > +			continue;
> > > +		}
> > > +
> > > +		val = readl(pcie->appl_base + APPL_DEBUG);
> > > +		val &= APPL_DEBUG_LTSSM_STATE_MASK;
> > > +		val >>= APPL_DEBUG_LTSSM_STATE_SHIFT;
> > > +		tmp = readl(pcie->appl_base + APPL_LINK_STATUS);
> > > +		tmp &= APPL_LINK_STATUS_RDLH_LINK_UP;
> > > +		if (!(val == 0x11 && !tmp)) {
> > > +			dev_info(pci->dev, "Link is down\n");
> > > +			return 0;
> > > +		}
> > > +
> > > +		dev_info(pci->dev, "Link is down in DLL");
> > > +		dev_info(pci->dev, "Trying again with DLFE disabled\n");
> > > +		/* Disable LTSSM */
> > > +		val = readl(pcie->appl_base + APPL_CTRL);
> > > +		val &= ~APPL_CTRL_LTSSM_EN;
> > > +		writel(val, pcie->appl_base + APPL_CTRL);
> > > +
> > > +		reset_control_assert(pcie->core_rst);
> > > +		reset_control_deassert(pcie->core_rst);
> > > +
> > > +		offset = dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_DLF);
> > > +		val = dw_pcie_readl_dbi(pci, offset + PCI_DLF_CAP);
> > > +		val &= ~PCI_DLF_EXCHANGE_ENABLE;
> > > +		dw_pcie_writel_dbi(pci, offset, val);
> > > +
> > > +		/* Retry now with DLF Exchange disabled */
> > > +		goto core_init;
> > > +	}
> > > +	dev_dbg(pci->dev, "Link is up\n");
> > > +
> > > +	speed = (dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
> > > +		 PCI_EXP_LNKSTA_CLS);
> > 
> > No need for the outer parentheses.
> Done.
> 
> > 
> > > +	clk_set_rate(pcie->core_clk, pcie_gen_freq[speed - 1]);
> > > +
> > > +	tegra_pcie_enable_interrupts(pp);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int tegra_pcie_dw_link_up(struct dw_pcie *pci)
> > > +{
> > > +	struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
> > > +	u32 val = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA);
> > > +
> > > +	return !!(val & PCI_EXP_LNKSTA_DLLLA);
> > > +}
> > > +
> > > +static void tegra_pcie_set_msi_vec_num(struct pcie_port *pp)
> > > +{
> > > +	pp->num_vectors = MAX_MSI_IRQS;
> > > +}
> > > +
> > > +static const struct dw_pcie_ops tegra_dw_pcie_ops = {
> > > +	.link_up = tegra_pcie_dw_link_up,
> > > +};
> > > +
> > > +static struct dw_pcie_host_ops tegra_pcie_dw_host_ops = {
> > > +	.rd_own_conf = tegra_pcie_dw_rd_own_conf,
> > > +	.wr_own_conf = tegra_pcie_dw_wr_own_conf,
> > > +	.host_init = tegra_pcie_dw_host_init,
> > > +	.set_num_vectors = tegra_pcie_set_msi_vec_num,
> > > +};
> > > +
> > > +static void tegra_pcie_disable_phy(struct tegra_pcie_dw *pcie)
> > > +{
> > > +	u32 phy_count = pcie->phy_count;
> > > +
> > > +	while (phy_count--) {
> > > +		phy_power_off(pcie->phys[phy_count]);
> > > +		phy_exit(pcie->phys[phy_count]);
> > > +	}
> > > +}
> > > +
> > > +static int tegra_pcie_enable_phy(struct tegra_pcie_dw *pcie)
> > > +{
> > > +	u32 phy_count = pcie->phy_count;
> > 
> > This seems unnecessary in this function.
> > 
> > > +	int ret;
> > > +	u32 i;
> > 
> > Can be unsigned int to match pcie->phy_count.
> > 
> > > +
> > > +	for (i = 0; i < phy_count; i++) {
> > > +		ret = phy_init(pcie->phys[i]);
> > > +		if (ret < 0)
> > > +			goto err_phy_init;
> > > +
> > > +		ret = phy_power_on(pcie->phys[i]);
> > > +		if (ret < 0) {
> > > +			phy_exit(pcie->phys[i]);
> > > +			goto err_phy_power_on;
> > > +		}
> > > +	}
> > > +
> > > +	return 0;
> > > +
> > > +	while (i >= 0) {
> > 
> > Oh... looks like this can't be unsigned, otherwise you'll be infinitely
> > repeating this loop. Perhaps you can rewrite it like this to avoid that:
> > 
> > 	while (i--) {
> > 		...
> > 	}
> > 
> > That's the most idiomatic way to unwind in my opinion.
> It is written this way to handle situations where an intermediate may phy_init() fail
> or a phy_power_on() may fail after phy_init() succeeds. This while loops gracefully
> undoes whatever has been done already.

It should do that even if you move to a more idiomatic way of writing
the loop, right? The corner case here is if you fail on the first PHY
because then i is 0. However, since on failure you jump right into the
loop, your loop variable will be unmodified, right?

That would incidentally also get rid of the slightly odd nature of the
code. One other thing regarding jump labels: it's usually better to call
them after the action that they perform (see also section 7 in
Documentation/process/coding-style.rst).

The following should be identical to your code, but a lot more
idiomatic:

	static int tegra_pcie_enable_phy(struct tegra_pcie_dw *pcie)
	{
		unsigned int i;
		int ret;

		for (i = 0; i < pcie->phy_count; i++) {
			ret = phy_init(pcie->phys[i]);
			if (ret < 0)
				goto phy_power_off;

			ret = phy_power_on(pcie->phys[i]);
			if (ret < 0)
				goto phy_exit;
		}

		return 0;

	phy_power_off:
		while (i--) {
			phy_power_off(pcie->phys[i]);
	phy_exit:
			phy_exit(pcie->phys[i]);
		}

		return ret;
	}

For failures on the first iteration, the above will jump to
phy_power_off:, evaluate i--, see that it's 0 and do nothing, which is
good because nothing is needed. On phy_power_on() failure it will jump
to phy_exit: and call phy_exit(pcie->phys[0]), which undoes what it did
for that PHY, then evaluate i-- and see that it's 0 and abort.

For all subsequent iterations it will do essentially the same thing,
except that when evaluating i-- it will see the 1, 2, ... and step into
the loop, at which point the value in i will be decremented and undo the
setup for earlier PHYs.

> 
> > 
> > > +		phy_power_off(pcie->phys[i]);
> > > +err_phy_power_on:
> > > +		phy_exit(pcie->phys[i]);

One other thing I just noticed after looking at this more closely: there
doesn't seem to be a need to call phy_exit() in the case phy_power_on()
fails since you already jump to this label (err_phy_power_on:) in that
case, where you already have the phy_exit() call.

> > > +err_phy_init:
> > > +		i--;
> > > +	}
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static int tegra_pcie_dw_parse_dt(struct tegra_pcie_dw *pcie)
> > > +{
> > > +	struct device_node *np = pcie->dev->of_node;
> > > +	int ret;
> > > +
> > > +	ret = of_property_read_u32(np, "nvidia,aspm-cmrt-us", &pcie->aspm_cmrt);
> > > +	if (ret < 0) {
> > > +		dev_info(pcie->dev, "Failed to read ASPM T_cmrt: %d\n", ret);
> > > +		return ret;
> > > +	}
> > > +
> > > +	ret = of_property_read_u32(np, "nvidia,aspm-pwr-on-t-us",
> > > +				   &pcie->aspm_pwr_on_t);
> > > +	if (ret < 0)
> > > +		dev_info(pcie->dev, "Failed to read ASPM Power On time: %d\n",
> > > +			 ret);
> > > +
> > > +	ret = of_property_read_u32(np, "nvidia,aspm-l0s-entrance-latency-us",
> > > +				   &pcie->aspm_l0s_enter_lat);
> > > +	if (ret < 0)
> > > +		dev_info(pcie->dev,
> > > +			 "Failed to read ASPM L0s Entrance latency: %d\n", ret);
> > > +
> > > +	ret = of_property_read_u32(np, "num-lanes", &pcie->num_lanes);
> > > +	if (ret < 0) {
> > > +		dev_err(pcie->dev, "Failed to read num-lanes: %d\n", ret);
> > > +		return ret;
> > > +	}
> > > +
> > > +	pcie->max_speed = of_pci_get_max_link_speed(np);
> > > +
> > > +	ret = of_property_read_u32_index(np, "nvidia,bpmp", 1, &pcie->cid);
> > > +	if (ret) {
> > > +		dev_err(pcie->dev, "Failed to read Controller-ID: %d\n", ret);
> > > +		return ret;
> > > +	}
> > > +
> > > +	pcie->phy_count = of_property_count_strings(np, "phy-names");
> > > +	if (pcie->phy_count < 0) {
> > > +		dev_err(pcie->dev, "Failed to find phy entries\n");
> > > +		return pcie->phy_count;
> > > +	}
> > > +
> > > +	if (of_property_read_bool(np, "nvidia,update-fc-fixup"))
> > > +		pcie->update_fc_fixup = true;
> > > +
> > > +	pcie->supports_clkreq =
> > > +		of_property_read_bool(pcie->dev->of_node, "supports-clkreq");
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int tegra_pcie_bpmp_set_ctrl_state(struct tegra_pcie_dw *pcie,
> > > +					  int enable)
> > 
> > Perhaps make this a boolean? That's not an exact match for the
> > req.controller_state.enable field defined in the ABI, but it's a bit
> > closer than an int. Also, boolean is effectively what the ABI allows,
> > so might as well use that.
> I want to return the error code of tegra_bpmp_transfer_atomic()/
> tegra_bpmp_transfer() directly and they have int return type. I'm not sure
> how having boolean is better here? Can you please give more details?

Sorry for being unclear. I was referring to the enable parameter.

> 
> > 
> > > +{
> > > +	struct mrq_uphy_response resp;
> > > +	struct tegra_bpmp_message msg;
> > > +	struct mrq_uphy_request req;
> > > +	int err;
> > > +
> > > +	if (pcie->cid == CTRL_5)
> > > +		return 0;
> > > +
> > > +	memset(&req, 0, sizeof(req));
> > > +	memset(&resp, 0, sizeof(resp));
> > > +
> > > +	req.cmd = CMD_UPHY_PCIE_CONTROLLER_STATE;
> > > +	req.controller_state.pcie_controller = pcie->cid;
> > > +	req.controller_state.enable = enable;
> > > +
> > > +	memset(&msg, 0, sizeof(msg));
> > > +	msg.mrq = MRQ_UPHY;
> > > +	msg.tx.data = &req;
> > > +	msg.tx.size = sizeof(req);
> > > +	msg.rx.data = &resp;
> > > +	msg.rx.size = sizeof(resp);
> > > +
> > > +	if (irqs_disabled())
> > > +		err = tegra_bpmp_transfer_atomic(pcie->bpmp, &msg);
> > > +	else
> > > +		err = tegra_bpmp_transfer(pcie->bpmp, &msg);
> > > +
> > > +	return err;
> > > +}
> > > +
> > > +static void tegra_pcie_downstream_dev_to_D0(struct tegra_pcie_dw *pcie)
> > > +{
> > > +	struct pcie_port *pp = &pcie->pci.pp;
> > > +	struct pci_dev *pdev;
> > > +	struct pci_bus *child;
> > > +
> > > +	list_for_each_entry(child, &pp->root_bus->children, node) {
> > > +		/* Bring downstream devices to D0 if they are not already in */
> > > +		if (child->parent == pp->root_bus)
> > > +			break;
> > > +	}
> > > +	list_for_each_entry(pdev, &child->devices, bus_list) {
> > > +		if (PCI_FUNC(pdev->devfn) == 0) {
> > 
> > Why restrict this to function 0? What about other potential functions?
> Yes. This should be extended to other functions as well. I'll change it from
> PCI_FUNC() to PCI_SLOT() to look for device zero.

Why restrict this to slot 0?

> > Also, if child devices are not in D0 at this point, isn't that an error?
> No. In fact, they are not going to be in D0. They would be in D3_hot or whichever
> low power state they support. PCIe sub-system makes sure that.
> 
> > Perhaps we should check the power state of the device here and output a
> > warning if it's not in D0 so that we can track down which device drivers
> > are buggy?
> Since they are anyway not going to be in D0 and we are bringing all of them to D0
> here, I think it is not required.

Is it safe to take the devices to D0 if the driver has only set them to
D3_hot or some other state? Will the drivers know and unterstand how to
handle other states when resuming?

Thierry

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