Date:   Tue, 20 Nov 2018 21:15:31 +0900
From:   Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
To:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>
Cc:     Bjorn Helgaas <bhelgaas@...gle.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        <linux-pci@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        Masami Hiramatsu <masami.hiramatsu@...aro.org>,
        Jassi Brar <jaswinder.singh@...aro.org>,
        Gustavo Pimentel <gustavo.pimentel@...opsys.com>
Subject: Re: [RESEND PATCH v3 2/2] PCI: uniphier: Add UniPhier PCIe host controller support

Hi Lorenzo,

Thank you for reviewing it.

On Mon, 19 Nov 2018 16:17:20 +0000 <lorenzo.pieralisi@....com> wrote:

> On Tue, Oct 16, 2018 at 02:27:21PM +0900, Kunihiko Hayashi wrote:
> > This introduces specific glue layer for UniPhier platform to support
> > PCIe host controller that is based on the DesignWare PCIe core, and
> > this driver supports Root Complex (host) mode.
> > 
> > Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
> > ---
> >  drivers/pci/controller/dwc/Kconfig         |   9 +
> >  drivers/pci/controller/dwc/Makefile        |   1 +
> >  drivers/pci/controller/dwc/pcie-uniphier.c | 433 +++++++++++++++++++++++++++++
> 
> The driver needs a MAINTAINERS entry too.

Okay. I'll add it in v4.


> >  3 files changed, 443 insertions(+)
> >  create mode 100644 drivers/pci/controller/dwc/pcie-uniphier.c
> > 
> > diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
> > index 91b0194..d8fdb02 100644
> > --- a/drivers/pci/controller/dwc/Kconfig
> > +++ b/drivers/pci/controller/dwc/Kconfig
> > @@ -193,4 +193,13 @@ config PCIE_HISI_STB
> >  	help
> >            Say Y here if you want PCIe controller support on HiSilicon STB SoCs
> >  
> > +config PCIE_UNIPHIER
> > +	bool "Socionext UniPhier PCIe controllers"
> > +	depends on OF && (ARCH_UNIPHIER || COMPILE_TEST)
> > +	depends on PCI_MSI_IRQ_DOMAIN
> > +	select PCIE_DW_HOST
> > +	help
> > +	  Say Y here if you want PCIe controller support on UniPhier SoCs.
> > +	  This driver supports LD20 and PXs3 SoCs.
> > +
> >  endmenu
> > diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
> > index 5d2ce72..cbde733 100644
> > --- a/drivers/pci/controller/dwc/Makefile
> > +++ b/drivers/pci/controller/dwc/Makefile
> > @@ -14,6 +14,7 @@ obj-$(CONFIG_PCIE_ARMADA_8K) += pcie-armada8k.o
> >  obj-$(CONFIG_PCIE_ARTPEC6) += pcie-artpec6.o
> >  obj-$(CONFIG_PCIE_KIRIN) += pcie-kirin.o
> >  obj-$(CONFIG_PCIE_HISI_STB) += pcie-histb.o
> > +obj-$(CONFIG_PCIE_UNIPHIER) += pcie-uniphier.o
> >  
> >  # The following drivers are for devices that use the generic ACPI
> >  # pci_root.c driver but don't support standard ECAM config access.
> > diff --git a/drivers/pci/controller/dwc/pcie-uniphier.c b/drivers/pci/controller/dwc/pcie-uniphier.c
> > new file mode 100644
> > index 0000000..2689449
> > --- /dev/null
> > +++ b/drivers/pci/controller/dwc/pcie-uniphier.c
> > @@ -0,0 +1,433 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * PCIe host controller driver for UniPhier SoCs
> > + * Copyright 2018 Socionext Inc.
> > + * Author: Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
> > + */
> > +
> > +#include <linux/bitops.h>
> > +#include <linux/bitfield.h>
> > +#include <linux/clk.h>
> > +#include <linux/delay.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/iopoll.h>
> > +#include <linux/irqchip/chained_irq.h>
> > +#include <linux/irqdomain.h>
> > +#include <linux/module.h>
> > +#include <linux/of_irq.h>
> > +#include <linux/pci.h>
> > +#include <linux/phy/phy.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/reset.h>
> > +
> > +#include "pcie-designware.h"
> > +
> > +#define PCL_PINCTRL0			0x002c
> > +#define PCL_PERST_PLDN_REGEN		BIT(12)
> > +#define PCL_PERST_NOE_REGEN		BIT(11)
> > +#define PCL_PERST_OUT_REGEN		BIT(8)
> > +#define PCL_PERST_PLDN_REGVAL		BIT(4)
> > +#define PCL_PERST_NOE_REGVAL		BIT(3)
> > +#define PCL_PERST_OUT_REGVAL		BIT(0)
> > +
> > +#define PCL_PIPEMON			0x0044
> > +#define PCL_PCLK_ALIVE			BIT(15)
> > +
> > +#define PCL_APP_READY_CTRL		0x8008
> > +#define PCL_APP_LTSSM_ENABLE		BIT(0)
> > +
> > +#define PCL_APP_PM0			0x8078
> > +#define PCL_SYS_AUX_PWR_DET		BIT(8)
> > +
> > +#define PCL_RCV_INT			0x8108
> > +#define PCL_RCV_INT_ALL_ENABLE		GENMASK(20, 17)
> > +#define PCL_CFG_BW_MGT_STATUS		BIT(4)
> > +#define PCL_CFG_LINK_AUTO_BW_STATUS	BIT(3)
> > +#define PCL_CFG_AER_RC_ERR_MSI_STATUS	BIT(2)
> > +#define PCL_CFG_PME_MSI_STATUS		BIT(1)
> > +
> > +#define PCL_RCV_INTX			0x810c
> > +#define PCL_RCV_INTX_ALL_ENABLE		GENMASK(19, 16)
> > +#define PCL_RCV_INTX_ALL_STATUS		GENMASK(3, 0)
> > +
> > +#define PCL_STATUS_LINK			0x8140
> > +#define PCL_RDLH_LINK_UP		BIT(1)
> > +#define PCL_XMLH_LINK_UP		BIT(0)
> > +
> > +struct uniphier_pcie_priv {
> > +	void __iomem *base;
> > +	struct dw_pcie pci;
> > +	struct clk *clk;
> > +	struct reset_control *rst;
> > +	struct phy *phy;
> > +	struct irq_domain *legacy_irq_domain;
> > +};
> > +
> > +#define to_uniphier_pcie(x)	dev_get_drvdata((x)->dev)
> > +
> > +static void uniphier_pcie_ltssm_enable(struct uniphier_pcie_priv *priv)
> > +{
> > +	u32 val;
> > +
> > +	val = readl(priv->base + PCL_APP_READY_CTRL);
> > +	val |= PCL_APP_LTSSM_ENABLE;
> > +	writel(val, priv->base + PCL_APP_READY_CTRL);
> > +}
> > +
> > +static void uniphier_pcie_ltssm_disable(struct uniphier_pcie_priv *priv)
> > +{
> > +	u32 val;
> > +
> > +	val = readl(priv->base + PCL_APP_READY_CTRL);
> > +	val &= ~PCL_APP_LTSSM_ENABLE;
> > +	writel(val, priv->base + PCL_APP_READY_CTRL);
> > +}
> 
> A single function with an "enable" parameter would do.

I'll merge them into a single function.


> > +static void uniphier_pcie_init_rc(struct uniphier_pcie_priv *priv)
> > +{
> > +	u32 val;
> > +
> > +	/* use auxiliary power detection */
> > +	val = readl(priv->base + PCL_APP_PM0);
> > +	val |= PCL_SYS_AUX_PWR_DET;
> > +	writel(val, priv->base + PCL_APP_PM0);
> > +
> > +	/* assert PERST# */
> > +	val = readl(priv->base + PCL_PINCTRL0);
> > +	val &= ~(PCL_PERST_NOE_REGVAL | PCL_PERST_OUT_REGVAL
> > +		 | PCL_PERST_PLDN_REGVAL);
> > +	val |= PCL_PERST_NOE_REGEN | PCL_PERST_OUT_REGEN
> > +		| PCL_PERST_PLDN_REGEN;
> > +	writel(val, priv->base + PCL_PINCTRL0);
> > +
> > +	uniphier_pcie_ltssm_disable(priv);
> > +
> > +	usleep_range(100000, 200000);
> > +
> > +	/* deassert PERST# */
> > +	val = readl(priv->base + PCL_PINCTRL0);
> > +	val |= PCL_PERST_OUT_REGVAL | PCL_PERST_OUT_REGEN;
> > +	writel(val, priv->base + PCL_PINCTRL0);
> > +}
> > +
> > +static int uniphier_pcie_wait_rc(struct uniphier_pcie_priv *priv)
> > +{
> > +	u32 status;
> > +	int ret;
> > +
> > +	/* wait PIPE clock */
> > +	ret = readl_poll_timeout(priv->base + PCL_PIPEMON, status,
> > +				 status & PCL_PCLK_ALIVE, 100000, 1000000);
> > +	if (ret) {
> > +		dev_err(priv->pci.dev,
> > +			"Failed to initialize controller in RC mode\n");
> > +		return ret;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static int uniphier_pcie_link_up(struct dw_pcie *pci)
> 
> This function returns a bool value, make it return a bool.

This function is registered in struct dw_pcie_ops.link_up, that is defined
in pcie-designware.h as follows:

       int     (*link_up)(struct dw_pcie *pcie);

Changing the return type of this function makes type mismatch,
so I think it's difficult to change it.


> > +{
> > +	struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci);
> > +	u32 val, mask;
> > +
> > +	val = readl(priv->base + PCL_STATUS_LINK);
> > +	mask = PCL_RDLH_LINK_UP | PCL_XMLH_LINK_UP;
> > +
> > +	return (val & mask) == mask;
> > +}
> > +
> > +static int uniphier_pcie_establish_link(struct dw_pcie *pci)
> > +{
> > +	struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci);
> > +	int ret;
> > +
> > +	if (dw_pcie_link_up(pci))
> > +		return 0;
> > +
> > +	uniphier_pcie_ltssm_enable(priv);
> > +
> > +	ret = dw_pcie_wait_for_link(pci);
> 
> dw_pcie_wait_for_link() already prints an error, I do not see
> what this additional warning is adding.

Surely it's redundant, enough for previous error message.

> > +	if (ret == -ETIMEDOUT)
> > +		dev_warn(pci->dev, "Link not up\n");
> 
> 
> > +
> > +	return ret;
> > +}
> > +
> > +static void uniphier_pcie_stop_link(struct dw_pcie *pci)
> > +{
> > +	struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci);
> > +
> > +	uniphier_pcie_ltssm_disable(priv);
> > +}
> > +
> > +static int uniphier_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
> > +				  irq_hw_number_t hwirq)
> > +{
> > +	irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
> > +	irq_set_chip_data(irq, domain->host_data);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct irq_domain_ops uniphier_intx_domain_ops = {
> > +	.map = uniphier_pcie_intx_map,
> > +	.xlate = pci_irqd_intx_xlate,
> > +};
> 
> - You should define a proper IRQ chip implementation
> - INTX are level interrupts, so handle_level_irq() is the flow handler
> - Using pci_irqd_intx_xlate() is wrong, please update the DT bindings
>   as I explained
> 
> Take a look at pci-ftpci100.c and use that approach to implement INTX
> handling.

I understand. With referenct to pci-ftpci100.c,
I'll change to level interrupts, remove xlate, replace dummy_irq_chip with
own irqchip including mask/unmask/ack functions.


> > +static void uniphier_pcie_irq_enable(struct uniphier_pcie_priv *priv)
> > +{
> > +	writel(PCL_RCV_INT_ALL_ENABLE, priv->base + PCL_RCV_INT);
> > +	writel(PCL_RCV_INTX_ALL_ENABLE, priv->base + PCL_RCV_INTX);
> > +}
> > +
> > +static void uniphier_pcie_irq_disable(struct uniphier_pcie_priv *priv)
> > +{
> > +	writel(0, priv->base + PCL_RCV_INT);
> > +	writel(0, priv->base + PCL_RCV_INTX);
> > +}
> > +
> > +static void uniphier_pcie_irq_handler(struct irq_desc *desc)
> > +{
> > +	struct pcie_port *pp = irq_desc_get_handler_data(desc);
> > +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> > +	struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci);
> > +	struct irq_chip *chip = irq_desc_get_chip(desc);
> > +	unsigned long reg;
> > +	u32 val, bit, virq;
> > +
> > +	/* INT for debug */
> > +	val = readl(priv->base + PCL_RCV_INT);
> > +
> > +	if (val & PCL_CFG_BW_MGT_STATUS)
> > +		dev_dbg(pci->dev, "Link Bandwidth Management Event\n");
> > +	if (val & PCL_CFG_LINK_AUTO_BW_STATUS)
> > +		dev_dbg(pci->dev, "Link Autonomous Bandwidth Event\n");
> > +	if (val & PCL_CFG_AER_RC_ERR_MSI_STATUS)
> > +		dev_dbg(pci->dev, "Root Error\n");
> > +	if (val & PCL_CFG_PME_MSI_STATUS)
> > +		dev_dbg(pci->dev, "PME Interrupt\n");
> > +
> > +	writel(val, priv->base + PCL_RCV_INT);
> 
> What's writing to PCL_RCV_INT needed for ?

Each status bit is cleared by writing 1 to the bit.
This writel() can clear asserted bit.


> > +	/* INTx */
> > +	chained_irq_enter(chip, desc);
> > +
> > +	val = readl(priv->base + PCL_RCV_INTX);
> > +	reg = FIELD_GET(PCL_RCV_INTX_ALL_STATUS, val);
> > +
> > +	for_each_set_bit(bit, &reg, PCI_NUM_INTX) {
> > +		virq = irq_linear_revmap(priv->legacy_irq_domain, bit);
> > +		generic_handle_irq(virq);
> > +	}
> > +
> > +	writel(val, priv->base + PCL_RCV_INTX);
> > +
> > +	chained_irq_exit(chip, desc);
> > +}
> > +
> > +static int uniphier_pcie_config_legacy_irq(struct pcie_port *pp)
> > +{
> > +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> > +	struct uniphier_pcie_priv *priv = to_uniphier_pcie(pci);
> > +	struct device_node *np = pci->dev->of_node;
> > +	struct device_node *np_intc;
> > +
> > +	np_intc = of_get_child_by_name(np, "legacy-interrupt-controller");
> > +	if (!np_intc) {
> > +		dev_err(pci->dev, "Failed to get legacy-interrupt-controller node\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	pp->irq = irq_of_parse_and_map(np_intc, 0);
> > +	if (!pp->irq) {
> > +		dev_err(pci->dev, "Failed to get an IRQ entry in legacy-interrupt-controller\n");
> > +		return -EINVAL;
> > +	}
> > +	irq_set_chained_handler_and_data(pp->irq, uniphier_pcie_irq_handler,
> > +					 pp);
> > +
> > +	priv->legacy_irq_domain = irq_domain_add_linear(np_intc, PCI_NUM_INTX,
> > +						&uniphier_intx_domain_ops, pp);
> > +	if (!priv->legacy_irq_domain) {
> > +		dev_err(pci->dev, "Failed to get INTx domain\n");
> > +		return -ENODEV;
> > +	}
> 
> 	priv->legacy_irq_domain = irq_domain_add_linear(np_intc, PCI_NUM_INTX,
> 						&uniphier_intx_domain_ops, pp);
> 	if (!priv->legacy_irq_domain) {
> 		dev_err(pci->dev, "Failed to get INTx domain\n");
> 		return -ENODEV;
> 	}
> 
> First add IRQs to the domain, then
> 
> 	irq_set_chained_handler_and_data(pp->irq, uniphier_pcie_irq_handler,
> 					 pp);
> 
> set up the cascaded handler.

I see. I'll change the order.

Thank you,

---
Best Regards,
Kunihiko Hayashi

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