RE: [PATCHv4 24/28] PCI: mobiveil: add PCIe Gen4 RC driver for NXP Layerscape SoCs

From: Z.q. Hou
Date: Tue Mar 12 2019 - 00:41:06 EST

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In reply to: Bjorn Helgaas: "Re: [PATCHv4 24/28] PCI: mobiveil: add PCIe Gen4 RC driver for NXP Layerscape SoCs"
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Hi Bjorn,

Thanks a lot for your comments!

> -----Original Message-----
> From: Bjorn Helgaas [mailto:helgaas@xxxxxxxxxx]
> Sent: 2019å3æ11æ 22:02
> To: Z.q. Hou <zhiqiang.hou@xxxxxxx>
> Cc: linux-pci@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> robh+dt@xxxxxxxxxx; mark.rutland@xxxxxxx; l.subrahmanya@xxxxxxxxxxxxxx;
> shawnguo@xxxxxxxxxx; Leo Li <leoyang.li@xxxxxxx>;
> lorenzo.pieralisi@xxxxxxx; catalin.marinas@xxxxxxx;
> will.deacon@xxxxxxx; Mingkai Hu <mingkai.hu@xxxxxxx>; M.h. Lian
> <minghuan.lian@xxxxxxx>; Xiaowei Bao <xiaowei.bao@xxxxxxx>
> Subject: Re: [PATCHv4 24/28] PCI: mobiveil: add PCIe Gen4 RC driver for NXP
> Layerscape SoCs
>
> On Mon, Mar 11, 2019 at 09:33:16AM +0000, Z.q. Hou wrote:
> > From: Hou Zhiqiang <Zhiqiang.Hou@xxxxxxx>
> >
> > This PCIe controller is based on the Mobiveil GPEX IP, which is
> > compatible with the PCI Expressâ Base Specification, Revision 4.0.
> >
> > Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@xxxxxxx>
> > Reviewed-by: Minghuan Lian <Minghuan.Lian@xxxxxxx>
> > ---
> > V4:
> > - no change
> >
> > drivers/pci/controller/mobiveil/Kconfig | 10 +
> > drivers/pci/controller/mobiveil/Makefile | 1 +
> > .../controller/mobiveil/pci-layerscape-gen4.c | 254 ++++++++++++++++++
> > .../pci/controller/mobiveil/pcie-mobiveil.h | 16 +-
> > 4 files changed, 279 insertions(+), 2 deletions(-) create mode
> > 100644 drivers/pci/controller/mobiveil/pci-layerscape-gen4.c
> >
> > diff --git a/drivers/pci/controller/mobiveil/Kconfig
> > b/drivers/pci/controller/mobiveil/Kconfig
> > index 64343c07bfed..3ddb7d6163a9 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 PCI_LAYERSCAPE_GEN4
> > + bool "Freescale Layerscpe PCIe Gen4 controller"
>
> "Layerscape"

Will fix in v5.

>
> > + 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.
> > endmenu
> > diff --git a/drivers/pci/controller/mobiveil/Makefile
> > b/drivers/pci/controller/mobiveil/Makefile
> > index 9fb6d1c6504d..ff66774ccac4 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_PCI_LAYERSCAPE_GEN4) += pci-layerscape-gen4.o
> > diff --git a/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c
> > b/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c
> > new file mode 100644
> > index 000000000000..174cbcac4059
> > --- /dev/null
> > +++ b/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c
> > @@ -0,0 +1,254 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * PCIe host controller driver for NXP Layerscape SoCs
>
> It would be nice to make "NXP Layerscape SoCs" a little more specific so we
> can tell how it's different from the existing pci-layerscape.c that says
> "Freescale Layerscape SoCs". I assume this driver only works with gen4
> parts.

Yes, it is only for NXP SoCs with Mobiveil PCIe Gen4 controller, and will add specific in v5.

>
> > + * Copyright 2018 NXP
>
> s/2018/2019/
>

Will fix in v5.

> > + *
> > + * Author: Zhiqiang Hou <Zhiqiang.Hou@xxxxxxx> */
> > +
> > +#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 (31)
>
> You mix constants that are
>
> - the bit position (like this), and
> - the actual bit mask, like PAB_INTP_RESET
>
> Pick one and use a single style. My personal preference is a plain hex bit
> mask, e.g.,
>
> #define PF_INT_STAT_PABRST 0x80000000
> #define PAB_INTP_RESET 0x00000002
>
> But some people like BIT() or the style you used for PAB_INTP_RESET:
>
> #define PAB_INTP_RESET BIT(1)
> #define PAB_INTP_RESET (0x1 << 1)
>
> I definitely don't like the simple bit position like this:
>
> #define PF_INT_STAT_PABRST 31
>
> because that means you have to repeat things like
> "1 << PF_INT_STAT_PABRST" everywhere you use it.
>

Will unify them in v5.

> > +#define PCIE_PF_DBG (0x7fc)
> > +#define PF_DBG_LTSSM_MASK (0x3f)
> > +#define PF_DBG_WE (31)
> > +#define PF_DBG_PABR (27)
>
> Parens are not needed around single constants like these.

Yes, thanks for your advice.

>
> > +#define LS_PCIE_G4_LTSSM_L0 0x2d /* L0 state */
> > +
> > +#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 = 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 == LS_PCIE_G4_LTSSM_L0)
> > + return 1;
> > +
> > + return 0;
> > +}
> > +
> > +static void ls_pcie_g4_reinit_hw(struct ls_pcie_g4 *pcie) {
> > + struct mobiveil_pcie *mv_pci = pcie->pci;
> > + 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 = csr_readl(mv_pci, PAB_ACTIVITY_STAT);
> > + } while (((val & 1 << PF_INT_STAT_PABRST) == 0 || act_stat) && to--);
> > + if (to < 0) {
> > + dev_err(&mv_pci->pdev->dev, "poll PABRST&PABACT timeout\n");
> > + return;
> > + }
> > +
> > + /* clear PEX_RESET bit in PEX_PF0_DBG register */
> > + val = ls_pcie_g4_pf_readl(pcie, PCIE_PF_DBG);
> > + val |= 1 << PF_DBG_WE;
> > + ls_pcie_g4_pf_writel(pcie, PCIE_PF_DBG, val);
> > +
> > + val = ls_pcie_g4_pf_readl(pcie, PCIE_PF_DBG);
> > + val |= 1 << PF_DBG_PABR;
> > + ls_pcie_g4_pf_writel(pcie, PCIE_PF_DBG, val);
> > +
> > + val = ls_pcie_g4_pf_readl(pcie, PCIE_PF_DBG);
> > + val &= ~(1 << PF_DBG_WE);
> > + ls_pcie_g4_pf_writel(pcie, PCIE_PF_DBG, val);
> > +
> > + mobiveil_host_init(mv_pci, true);
> > +
> > + to = 100;
> > + while (!ls_pcie_g4_link_up(mv_pci) && to--)
> > + usleep_range(200, 250);
> > + if (to < 0)
> > + dev_err(&mv_pci->pdev->dev, "PCIe link trainning timeout\n");
>
> s/trainning/training/
>

My typo, will fix in v5.

> > +}
> > +
> > +static irqreturn_t ls_pcie_g4_handler(int irq, void *dev_id)
>
> Function name should include "irq_handler" or "isr". Run
>
> git grep request_irq drivers/pci/controller/
>
> and follow the existing conventions.
>

Yes, will fix in v5.

> > +{
> > + struct ls_pcie_g4 *pcie = (struct ls_pcie_g4 *)dev_id;
> > + struct mobiveil_pcie *mv_pci = pcie->pci;
> > + u32 val;
> > +
> > + val = csr_readl(mv_pci, PAB_INTP_AMBA_MISC_STAT);
> > + if (!val)
> > + return IRQ_NONE;
> > +
> > + if (val & PAB_INTP_RESET)
> > + schedule_delayed_work(&pcie->dwork, msecs_to_jiffies(1));
> > +
> > + 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);
> > + u32 val;
> > + int ret;
> > +
> > + pcie->irq = platform_get_irq_byname(mv_pci->pdev, "intr");
> > + if (pcie->irq < 0) {
> > + dev_err(&mv_pci->pdev->dev, "Can't get 'intr' irq.\n");
>
> When you use &mv_pci->pdev->dev more than once, as you do here, please
> add
>
> struct device *dev = &mv_pci->pdev->dev;
>
> and use "dev" instead of repeating the whole "&mv_pci->pdev->dev"
> expression.
>
> s/irq./IRQ/ (Capitalize IRQ and omit period)
>

Will fix in v5.

> > + return pcie->irq;
> > + }
> > + ret = devm_request_irq(&mv_pci->pdev->dev, pcie->irq,
> > + ls_pcie_g4_handler, IRQF_SHARED,
> > + mv_pci->pdev->name, pcie);
> > + if (ret) {
> > + dev_err(&mv_pci->pdev->dev, "Can't register PCIe IRQ.\n");
>
> Omit period from message and maybe include the IRQ number.
>

Will add in v5.

> All your messages should start with lower-case or all should start with
> upper-case (the two in this function are capitalized, but the others are not).
>

Will unify them in v5.

> > + return ret;
> > + }
> > +
> > + /* Enable interrupts */
> > + val = PAB_INTP_INTX_MASK | PAB_INTP_MSI | PAB_INTP_RESET |
> > + PAB_INTP_PCIE_UE | PAB_INTP_IE_PMREDI | PAB_INTP_IE_EC;
> > + csr_writel(mv_pci, val, PAB_INTP_AMBA_MISC_ENB);
> > +
> > + 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 = csr_readw(mv_pci, PCI_BRIDGE_CONTROL);
> > + ctrl &= ~PCI_BRIDGE_CTL_BUS_RESET;
> > + csr_writew(mv_pci, ctrl, PCI_BRIDGE_CONTROL);
> > + ls_pcie_g4_reinit_hw(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 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;
> > + }
> > +
> > + pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> > + if (!pcie)
> > + return -ENOMEM;
> > +
> > + mv_pci = devm_kzalloc(dev, sizeof(*mv_pci), GFP_KERNEL);
> > + if (!mv_pci)
> > + return -ENOMEM;
> > +
> > + mv_pci->pdev = pdev;
> > + mv_pci->ops = &ls_pcie_g4_pab_ops;
> > + mv_pci->rp.ops = &ls_pcie_g4_rp_ops;
> > + pcie->pci = mv_pci;
> > +
> > + 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))
> > + return -ENODEV;
> > +
> > + 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 0f5303962e88..0ccd6cee5f8f 100644
> > --- a/drivers/pci/controller/mobiveil/pcie-mobiveil.h
> > +++ b/drivers/pci/controller/mobiveil/pcie-mobiveil.h
> > @@ -41,6 +41,8 @@
> > #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
> >
> > @@ -49,8 +51,18 @@
> >
> > #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 (0x1 << 1)
> > +#define PAB_INTP_MSI (0x1 << 3)
> > +#define PAB_INTP_INTA (0x1 << 5)
> > +#define PAB_INTP_INTB (0x1 << 6)
> > +#define PAB_INTP_INTC (0x1 << 7)
> > +#define PAB_INTP_INTD (0x1 << 8)
> > +#define PAB_INTP_PCIE_UE (0x1 << 9)
> > +#define PAB_INTP_IE_PMREDI (0x1 << 29)
> > +#define PAB_INTP_IE_EC (0x1 << 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
> >

Thanks,
Zhiqiang

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