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    SubjectRe: [PATCHv9 10/12] PCI: mobiveil: Add PCIe Gen4 RC driver for NXP Layerscape SoCs
    On Wed, Nov 20, 2019 at 03:46:23AM +0000, Z.q. Hou wrote:
    > From: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
    >
    > This PCIe controller is based on the Mobiveil GPEX IP, which is
    > compatible with the PCI Express™ Base Specification, Revision 4.0.
    >
    > Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
    > Reviewed-by: Minghuan Lian <Minghuan.Lian@nxp.com>
    > ---
    > drivers/pci/controller/mobiveil/Kconfig | 10 +
    > drivers/pci/controller/mobiveil/Makefile | 1 +
    > .../mobiveil/pcie-layerscape-gen4.c | 274 ++++++++++++++++++
    > .../pci/controller/mobiveil/pcie-mobiveil.h | 16 +-
    > 4 files changed, 299 insertions(+), 2 deletions(-)
    > create mode 100644 drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c
    >
    > diff --git a/drivers/pci/controller/mobiveil/Kconfig b/drivers/pci/controller/mobiveil/Kconfig
    > index 64343c07bfed..c823be8dab1c 100644
    > --- a/drivers/pci/controller/mobiveil/Kconfig
    > +++ b/drivers/pci/controller/mobiveil/Kconfig
    > @@ -21,4 +21,14 @@ config PCIE_MOBIVEIL_PLAT
    > Soft IP. It has up to 8 outbound and inbound windows
    > for address translation and it is a PCIe Gen4 IP.
    >
    > +config PCIE_LAYERSCAPE_GEN4
    > + bool "Freescale Layerscape PCIe Gen4 controller"
    > + depends on PCI
    > + depends on OF && (ARM64 || ARCH_LAYERSCAPE)
    > + depends on PCI_MSI_IRQ_DOMAIN
    > + select PCIE_MOBIVEIL_HOST
    > + help
    > + Say Y here if you want PCIe Gen4 controller support on
    > + Layerscape SoCs. The PCIe controller can work in RC or
    > + EP mode according to RCW[HOST_AGT_PEX] setting.

    I think you can remove the last sentence - it doesn't give any value
    to users of KConfig.


    > endmenu
    > diff --git a/drivers/pci/controller/mobiveil/Makefile b/drivers/pci/controller/mobiveil/Makefile
    > index 9fb6d1c6504d..99d879de32d6 100644
    > --- a/drivers/pci/controller/mobiveil/Makefile
    > +++ b/drivers/pci/controller/mobiveil/Makefile
    > @@ -2,3 +2,4 @@
    > obj-$(CONFIG_PCIE_MOBIVEIL) += pcie-mobiveil.o
    > obj-$(CONFIG_PCIE_MOBIVEIL_HOST) += pcie-mobiveil-host.o
    > obj-$(CONFIG_PCIE_MOBIVEIL_PLAT) += pcie-mobiveil-plat.o
    > +obj-$(CONFIG_PCIE_LAYERSCAPE_GEN4) += pcie-layerscape-gen4.o
    > diff --git a/drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c b/drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c
    > new file mode 100644
    > index 000000000000..6c0d3e2532db
    > --- /dev/null
    > +++ b/drivers/pci/controller/mobiveil/pcie-layerscape-gen4.c
    > @@ -0,0 +1,274 @@
    > +// SPDX-License-Identifier: GPL-2.0
    > +/*
    > + * PCIe Gen4 host controller driver for NXP Layerscape SoCs
    > + *
    > + * Copyright 2019 NXP
    > + *
    > + * Author: Zhiqiang Hou <Zhiqiang.Hou@nxp.com>
    > + */
    > +
    > +#include <linux/kernel.h>
    > +#include <linux/interrupt.h>
    > +#include <linux/init.h>
    > +#include <linux/of_pci.h>
    > +#include <linux/of_platform.h>
    > +#include <linux/of_irq.h>
    > +#include <linux/of_address.h>
    > +#include <linux/pci.h>
    > +#include <linux/platform_device.h>
    > +#include <linux/resource.h>
    > +#include <linux/mfd/syscon.h>
    > +#include <linux/regmap.h>
    > +
    > +#include "pcie-mobiveil.h"
    > +
    > +/* LUT and PF control registers */
    > +#define PCIE_LUT_OFF 0x80000
    > +#define PCIE_PF_OFF 0xc0000
    > +#define PCIE_PF_INT_STAT 0x18
    > +#define PF_INT_STAT_PABRST BIT(31)
    > +
    > +#define PCIE_PF_DBG 0x7fc
    > +#define PF_DBG_LTSSM_MASK 0x3f
    > +#define PF_DBG_LTSSM_L0 0x2d /* L0 state */
    > +#define PF_DBG_WE BIT(31)
    > +#define PF_DBG_PABR BIT(27)
    > +
    > +#define to_ls_pcie_g4(x) platform_get_drvdata((x)->pdev)
    > +
    > +struct ls_pcie_g4 {
    > + struct mobiveil_pcie pci;
    > + struct delayed_work dwork;
    > + int irq;
    > +};
    > +
    > +static inline u32 ls_pcie_g4_lut_readl(struct ls_pcie_g4 *pcie, u32 off)
    > +{
    > + return ioread32(pcie->pci.csr_axi_slave_base + PCIE_LUT_OFF + off);
    > +}
    > +
    > +static inline void ls_pcie_g4_lut_writel(struct ls_pcie_g4 *pcie,
    > + u32 off, u32 val)
    > +{
    > + iowrite32(val, pcie->pci.csr_axi_slave_base + PCIE_LUT_OFF + off);
    > +}
    > +
    > +static inline u32 ls_pcie_g4_pf_readl(struct ls_pcie_g4 *pcie, u32 off)
    > +{
    > + return ioread32(pcie->pci.csr_axi_slave_base + PCIE_PF_OFF + off);
    > +}
    > +
    > +static inline void ls_pcie_g4_pf_writel(struct ls_pcie_g4 *pcie,
    > + u32 off, u32 val)
    > +{
    > + iowrite32(val, pcie->pci.csr_axi_slave_base + PCIE_PF_OFF + off);
    > +}
    > +
    > +static bool ls_pcie_g4_is_bridge(struct ls_pcie_g4 *pcie)
    > +{
    > + struct mobiveil_pcie *mv_pci = &pcie->pci;
    > + u32 header_type;
    > +
    > + header_type = mobiveil_csr_readb(mv_pci, PCI_HEADER_TYPE);
    > + header_type &= 0x7f;
    > +
    > + return header_type == PCI_HEADER_TYPE_BRIDGE;
    > +}
    > +
    > +static int ls_pcie_g4_link_up(struct mobiveil_pcie *pci)
    > +{
    > + struct ls_pcie_g4 *pcie = to_ls_pcie_g4(pci);
    > + u32 state;
    > +
    > + state = ls_pcie_g4_pf_readl(pcie, PCIE_PF_DBG);
    > + state = state & PF_DBG_LTSSM_MASK;
    > +
    > + if (state == PF_DBG_LTSSM_L0)
    > + return 1;
    > +
    > + return 0;
    > +}
    > +
    > +static void ls_pcie_g4_disable_interrupt(struct ls_pcie_g4 *pcie)
    > +{
    > + struct mobiveil_pcie *mv_pci = &pcie->pci;
    > +
    > + mobiveil_csr_writel(mv_pci, 0, PAB_INTP_AMBA_MISC_ENB);
    > +}
    > +
    > +static void ls_pcie_g4_enable_interrupt(struct ls_pcie_g4 *pcie)
    > +{
    > + struct mobiveil_pcie *mv_pci = &pcie->pci;
    > + u32 val;
    > +
    > + /* Clear the interrupt status */
    > + mobiveil_csr_writel(mv_pci, 0xffffffff, PAB_INTP_AMBA_MISC_STAT);
    > +
    > + val = PAB_INTP_INTX_MASK | PAB_INTP_MSI | PAB_INTP_RESET |
    > + PAB_INTP_PCIE_UE | PAB_INTP_IE_PMREDI | PAB_INTP_IE_EC;
    > + mobiveil_csr_writel(mv_pci, val, PAB_INTP_AMBA_MISC_ENB);
    > +}
    > +
    > +static void ls_pcie_g4_reinit_hw(struct ls_pcie_g4 *pcie)
    > +{
    > + struct mobiveil_pcie *mv_pci = &pcie->pci;
    > + struct device *dev = &mv_pci->pdev->dev;
    > + u32 val, act_stat;
    > + int to = 100;
    > +
    > + /* Poll for pab_csb_reset to set and PAB activity to clear */
    > + do {
    > + usleep_range(10, 15);
    > + val = ls_pcie_g4_pf_readl(pcie, PCIE_PF_INT_STAT);
    > + act_stat = mobiveil_csr_readl(mv_pci, PAB_ACTIVITY_STAT);
    > + } while (((val & PF_INT_STAT_PABRST) == 0 || act_stat) && to--);
    > + if (to < 0) {
    > + dev_err(dev, "Poll PABRST&PABACT timeout\n");
    > + return;
    If a timeout happens here - the caller has no idea this has happened
    and yet the following work doesn't get done. Isn't this a problem?

    > + }
    > +
    > + /* clear PEX_RESET bit in PEX_PF0_DBG register */
    > + val = ls_pcie_g4_pf_readl(pcie, PCIE_PF_DBG);
    > + val |= PF_DBG_WE;
    > + ls_pcie_g4_pf_writel(pcie, PCIE_PF_DBG, val);
    > +
    > + val = ls_pcie_g4_pf_readl(pcie, PCIE_PF_DBG);
    > + val |= PF_DBG_PABR;
    > + ls_pcie_g4_pf_writel(pcie, PCIE_PF_DBG, val);
    > +
    > + val = ls_pcie_g4_pf_readl(pcie, PCIE_PF_DBG);
    > + val &= ~PF_DBG_WE;
    > + ls_pcie_g4_pf_writel(pcie, PCIE_PF_DBG, val);
    > +
    > + mobiveil_host_init(mv_pci, true);

    Can mobiveil_host_init fail?

    > +
    > + to = 100;
    > + while (!ls_pcie_g4_link_up(mv_pci) && to--)
    > + usleep_range(200, 250);
    > + if (to < 0)
    > + dev_err(dev, "PCIe link training timeout\n");
    > +}
    > +
    > +static irqreturn_t ls_pcie_g4_isr(int irq, void *dev_id)
    > +{
    > + struct ls_pcie_g4 *pcie = (struct ls_pcie_g4 *)dev_id;
    > + struct mobiveil_pcie *mv_pci = &pcie->pci;
    > + u32 val;
    > +
    > + val = mobiveil_csr_readl(mv_pci, PAB_INTP_AMBA_MISC_STAT);
    > + if (!val)
    > + return IRQ_NONE;
    > +
    > + if (val & PAB_INTP_RESET) {

    Can you explain why this is needed (perhaps also in the cover letter)?

    > + ls_pcie_g4_disable_interrupt(pcie);
    > + schedule_delayed_work(&pcie->dwork, msecs_to_jiffies(1));
    > + }
    > +
    > + mobiveil_csr_writel(mv_pci, val, PAB_INTP_AMBA_MISC_STAT);
    > +
    > + return IRQ_HANDLED;
    > +}
    > +
    > +static int ls_pcie_g4_interrupt_init(struct mobiveil_pcie *mv_pci)
    > +{
    > + struct ls_pcie_g4 *pcie = to_ls_pcie_g4(mv_pci);
    > + struct platform_device *pdev = mv_pci->pdev;
    > + struct device *dev = &pdev->dev;
    > + int ret;
    > +
    > + pcie->irq = platform_get_irq_byname(pdev, "intr");
    > + if (pcie->irq < 0) {
    > + dev_err(dev, "Can't get 'intr' IRQ, errno = %d\n", pcie->irq);
    > + return pcie->irq;
    > + }
    > + ret = devm_request_irq(dev, pcie->irq, ls_pcie_g4_isr,
    > + IRQF_SHARED, pdev->name, pcie);
    > + if (ret) {
    > + dev_err(dev, "Can't register PCIe IRQ, errno = %d\n", ret);
    > + return ret;
    > + }
    > +
    > + return 0;
    > +}
    > +
    > +static void ls_pcie_g4_reset(struct work_struct *work)
    > +{
    > + struct delayed_work *dwork = container_of(work, struct delayed_work,
    > + work);
    > + struct ls_pcie_g4 *pcie = container_of(dwork, struct ls_pcie_g4, dwork);
    > + struct mobiveil_pcie *mv_pci = &pcie->pci;
    > + u16 ctrl;
    > +
    > + ctrl = mobiveil_csr_readw(mv_pci, PCI_BRIDGE_CONTROL);
    > + ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;
    > + mobiveil_csr_writew(mv_pci, ctrl, PCI_BRIDGE_CONTROL);
    > + ls_pcie_g4_reinit_hw(pcie);
    > + ls_pcie_g4_enable_interrupt(pcie);
    > +}
    > +
    > +static struct mobiveil_rp_ops ls_pcie_g4_rp_ops = {
    > + .interrupt_init = ls_pcie_g4_interrupt_init,
    > +};
    > +
    > +static const struct mobiveil_pab_ops ls_pcie_g4_pab_ops = {
    > + .link_up = ls_pcie_g4_link_up,
    > +};
    > +
    > +static int __init ls_pcie_g4_probe(struct platform_device *pdev)
    > +{
    > + struct device *dev = &pdev->dev;
    > + struct pci_host_bridge *bridge;
    > + struct mobiveil_pcie *mv_pci;
    > + struct ls_pcie_g4 *pcie;
    > + struct device_node *np = dev->of_node;
    > + int ret;
    > +
    > + if (!of_parse_phandle(np, "msi-parent", 0)) {
    > + dev_err(dev, "Failed to find msi-parent\n");
    > + return -EINVAL;
    > + }
    > +
    > + bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
    > + if (!bridge)
    > + return -ENOMEM;
    > +
    > + pcie = pci_host_bridge_priv(bridge);
    > + mv_pci = &pcie->pci;
    > +
    > + mv_pci->pdev = pdev;
    > + mv_pci->ops = &ls_pcie_g4_pab_ops;
    > + mv_pci->rp.ops = &ls_pcie_g4_rp_ops;
    > + mv_pci->rp.bridge = bridge;
    > +
    > + platform_set_drvdata(pdev, pcie);
    > +
    > + INIT_DELAYED_WORK(&pcie->dwork, ls_pcie_g4_reset);
    > +
    > + ret = mobiveil_pcie_host_probe(mv_pci);
    > + if (ret) {
    > + dev_err(dev, "Fail to probe\n");
    > + return ret;
    > + }
    > +
    > + if (!ls_pcie_g4_is_bridge(pcie))

    Is this a check that could apply to all host bridge drivers and thus live
    in mobiveil_pcie_host_probe?

    > + return -ENODEV;
    > +
    > + ls_pcie_g4_enable_interrupt(pcie);

    Is there an issue here in that we enable interrupts *after* telling the kernel
    about our controller? (Same applies for bailing if the IP isn't a bridge).

    Thanks,

    Andrew Murray

    > +
    > + return 0;
    > +}
    > +
    > +static const struct of_device_id ls_pcie_g4_of_match[] = {
    > + { .compatible = "fsl,lx2160a-pcie", },
    > + { },
    > +};
    > +
    > +static struct platform_driver ls_pcie_g4_driver = {
    > + .driver = {
    > + .name = "layerscape-pcie-gen4",
    > + .of_match_table = ls_pcie_g4_of_match,
    > + .suppress_bind_attrs = true,
    > + },
    > +};
    > +
    > +builtin_platform_driver_probe(ls_pcie_g4_driver, ls_pcie_g4_probe);
    > diff --git a/drivers/pci/controller/mobiveil/pcie-mobiveil.h b/drivers/pci/controller/mobiveil/pcie-mobiveil.h
    > index 750a7fd95bc1..c57a68d2bac4 100644
    > --- a/drivers/pci/controller/mobiveil/pcie-mobiveil.h
    > +++ b/drivers/pci/controller/mobiveil/pcie-mobiveil.h
    > @@ -43,6 +43,8 @@
    > #define PAGE_LO_MASK 0x3ff
    > #define PAGE_SEL_OFFSET_SHIFT 10
    >
    > +#define PAB_ACTIVITY_STAT 0x81c
    > +
    > #define PAB_AXI_PIO_CTRL 0x0840
    > #define APIO_EN_MASK 0xf
    >
    > @@ -51,8 +53,18 @@
    >
    > #define PAB_INTP_AMBA_MISC_ENB 0x0b0c
    > #define PAB_INTP_AMBA_MISC_STAT 0x0b1c
    > -#define PAB_INTP_INTX_MASK 0x01e0
    > -#define PAB_INTP_MSI_MASK 0x8
    > +#define PAB_INTP_RESET BIT(1)
    > +#define PAB_INTP_MSI BIT(3)
    > +#define PAB_INTP_INTA BIT(5)
    > +#define PAB_INTP_INTB BIT(6)
    > +#define PAB_INTP_INTC BIT(7)
    > +#define PAB_INTP_INTD BIT(8)
    > +#define PAB_INTP_PCIE_UE BIT(9)
    > +#define PAB_INTP_IE_PMREDI BIT(29)
    > +#define PAB_INTP_IE_EC BIT(30)
    > +#define PAB_INTP_MSI_MASK PAB_INTP_MSI
    > +#define PAB_INTP_INTX_MASK (PAB_INTP_INTA | PAB_INTP_INTB |\
    > + PAB_INTP_INTC | PAB_INTP_INTD)
    >
    > #define PAB_AXI_AMAP_CTRL(win) PAB_REG_ADDR(0x0ba0, win)
    > #define WIN_ENABLE_SHIFT 0
    > --
    > 2.17.1
    >

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