Re: [PATCH v5 1/4] pci: APM X-Gene PCIe controller driver

From: Liviu Dudau
Date: Wed Mar 26 2014 - 06:14:11 EST

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In reply to: Tanmay Inamdar: "Re: [PATCH v5 1/4] pci: APM X-Gene PCIe controller driver"
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On Tue, Mar 25, 2014 at 10:12:14PM +0000, Tanmay Inamdar wrote:
> Hello Liviu,
>
> Thanks for taking a look. Please see inline.
>
> On Tue, Mar 25, 2014 at 7:02 AM, Liviu Dudau <Liviu.Dudau@xxxxxxx> wrote:
> > On Wed, Mar 19, 2014 at 11:12:39PM +0000, Tanmay Inamdar wrote:
> >> This patch adds the AppliedMicro X-Gene SOC PCIe controller driver.
> >> X-Gene PCIe controller supports maximum up to 8 lanes and GEN3 speed.
> >> X-Gene SOC supports maximum 5 PCIe ports.
> >>
> >> Signed-off-by: Tanmay Inamdar <tinamdar@xxxxxxx>
> >
> > Hi Tanmay,
> >
> > Some comments below.
> >
> >> ---
> >> drivers/pci/host/Kconfig | 10 +
> >> drivers/pci/host/Makefile | 1 +
> >> drivers/pci/host/pci-xgene.c | 725 ++++++++++++++++++++++++++++++++++++++++++
> >> 3 files changed, 736 insertions(+)
> >> create mode 100644 drivers/pci/host/pci-xgene.c
> >>
> >> diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
> >> index 47d46c6..19ce97d 100644
> >> --- a/drivers/pci/host/Kconfig
> >> +++ b/drivers/pci/host/Kconfig
> >> @@ -33,4 +33,14 @@ config PCI_RCAR_GEN2
> >> There are 3 internal PCI controllers available with a single
> >> built-in EHCI/OHCI host controller present on each one.
> >>
> >> +config PCI_XGENE
> >> + bool "X-Gene PCIe controller"
> >> + depends on ARCH_XGENE
> >> + depends on OF
> >> + select PCIEPORTBUS
> >> + help
> >> + Say Y here if you want internal PCI support on APM X-Gene SoC.
> >> + There are 5 internal PCIe ports available. Each port is GEN3 capable
> >> + and have varied lanes from x1 to x8.
> >> +
> >> endmenu
> >> diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
> >> index 13fb333..34c7c36 100644
> >> --- a/drivers/pci/host/Makefile
> >> +++ b/drivers/pci/host/Makefile
> >> @@ -4,3 +4,4 @@ obj-$(CONFIG_PCI_IMX6) += pci-imx6.o
> >> obj-$(CONFIG_PCI_MVEBU) += pci-mvebu.o
> >> obj-$(CONFIG_PCI_TEGRA) += pci-tegra.o
> >> obj-$(CONFIG_PCI_RCAR_GEN2) += pci-rcar-gen2.o
> >> +obj-$(CONFIG_PCI_XGENE) += pci-xgene.o
> >> diff --git a/drivers/pci/host/pci-xgene.c b/drivers/pci/host/pci-xgene.c
> >> new file mode 100644
> >> index 0000000..9e312f6
> >> --- /dev/null
> >> +++ b/drivers/pci/host/pci-xgene.c
> >> @@ -0,0 +1,725 @@
> >> +/**
> >> + * APM X-Gene PCIe Driver
> >> + *
> >> + * Copyright (c) 2013 Applied Micro Circuits Corporation.
> >> + *
> >> + * Author: Tanmay Inamdar <tinamdar@xxxxxxx>.
> >> + *
> >> + * This program is free software; you can redistribute it and/or modify it
> >> + * under the terms of the GNU General Public License as published by the
> >> + * Free Software Foundation; either version 2 of the License, or (at your
> >> + * option) any later version.
> >> + *
> >> + * This program is distributed in the hope that it will be useful,
> >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> >> + * GNU General Public License for more details.
> >> + *
> >> + */
> >> +#include <linux/clk-private.h>
> >> +#include <linux/delay.h>
> >> +#include <linux/io.h>
> >> +#include <linux/jiffies.h>
> >> +#include <linux/memblock.h>
> >> +#include <linux/module.h>
> >> +#include <linux/of.h>
> >> +#include <linux/of_address.h>
> >> +#include <linux/of_irq.h>
> >> +#include <linux/of_pci.h>
> >> +#include <linux/pci.h>
> >> +#include <linux/platform_device.h>
> >> +#include <linux/slab.h>
> >> +
> >> +#define PCIECORE_LTSSM 0x4c
> >> +#define PCIECORE_CTLANDSTATUS 0x50
> >> +#define INTXSTATUSMASK 0x6c
> >> +#define PIM1_1L 0x80
> >> +#define IBAR2 0x98
> >> +#define IR2MSK 0x9c
> >> +#define PIM2_1L 0xa0
> >> +#define IBAR3L 0xb4
> >> +#define IR3MSKL 0xbc
> >> +#define PIM3_1L 0xc4
> >> +#define OMR1BARL 0x100
> >> +#define OMR2BARL 0x118
> >> +#define OMR3BARL 0x130
> >> +#define CFGBARL 0x154
> >> +#define CFGBARH 0x158
> >> +#define CFGCTL 0x15c
> >> +#define RTDID 0x160
> >> +#define BRIDGE_CFG_0 0x2000
> >> +#define BRIDGE_CFG_1 0x2004
> >> +#define BRIDGE_CFG_4 0x2010
> >> +#define BRIDGE_CFG_32 0x2030
> >> +#define BRIDGE_CFG_14 0x2038
> >> +#define BRIDGE_CTRL_1 0x2204
> >> +#define BRIDGE_CTRL_2 0x2208
> >> +#define BRIDGE_CTRL_5 0x2214
> >> +#define BRIDGE_STATUS_0 0x2600
> >> +#define MEM_RAM_SHUTDOWN 0xd070
> >> +#define BLOCK_MEM_RDY 0xd074
> >> +
> >> +#define DEVICE_PORT_TYPE_MASK 0x03c00000
> >> +#define PM_FORCE_RP_MODE_MASK 0x00000400
> >> +#define SWITCH_PORT_MODE_MASK 0x00000800
> >> +#define CLASS_CODE_MASK 0xffffff00
> >> +#define LINK_UP_MASK 0x00000100
> >> +#define AER_OPTIONAL_ERROR_EN 0xffc00000
> >> +#define XGENE_PCIE_DEV_CTRL 0x2f0f
> >> +#define AXI_EP_CFG_ACCESS 0x10000
> >> +#define ENABLE_ASPM 0x08000000
> >> +#define XGENE_PORT_TYPE_RC 0x05000000
> >> +#define BLOCK_MEM_RDY_VAL 0xFFFFFFFF
> >> +#define EN_COHERENCY 0xF0000000
> >> +#define EN_REG 0x00000001
> >> +#define OB_LO_IO 0x00000002
> >> +#define XGENE_PCIE_VENDORID 0xE008
> >> +#define XGENE_PCIE_DEVICEID 0xE004
> >> +#define XGENE_PCIE_ECC_TIMEOUT 10 /* ms */
> >> +#define XGENE_LTSSM_DETECT_WAIT 20 /* ms */
> >> +#define XGENE_LTSSM_L0_WAIT 4 /* ms */
> >> +#define SZ_1T (SZ_1G*1024ULL)
> >> +#define PIPE_PHY_RATE_RD(src) ((0xc000 & (u32)(src)) >> 0xe)
> >> +
> >> +struct xgene_pcie_port {
> >> + struct device_node *node;
> >> + struct device *dev;
> >> + struct clk *clk;
> >> + void __iomem *csr_base;
> >> + void __iomem *cfg_base;
> >> + u8 link_up;
> >> +};
> >> +
> >> +static inline u32 pcie_bar_low_val(u32 addr, u32 flags)
> >> +{
> >> + return (addr & PCI_BASE_ADDRESS_MEM_MASK) | flags;
> >> +}
> >> +
> >> +/* PCIE Configuration Out/In */
> >> +static inline void xgene_pcie_cfg_out32(void __iomem *addr, int offset, u32 val)
> >> +{
> >> + writel(val, addr + offset);
> >> +}
> >> +
> >> +static inline void xgene_pcie_cfg_out16(void __iomem *addr, int offset, u16 val)
> >> +{
> >> + u32 val32 = readl(addr + (offset & ~0x3));
> >> +
> >> + switch (offset & 0x3) {
> >> + case 2:
> >> + val32 &= ~0xFFFF0000;
> >> + val32 |= (u32)val << 16;
> >> + break;
> >> + case 0:
> >> + default:
> >> + val32 &= ~0xFFFF;
> >> + val32 |= val;
> >> + break;
> >> + }
> >> + writel(val32, addr + (offset & ~0x3));
> >> +}
> >> +
> >> +static inline void xgene_pcie_cfg_out8(void __iomem *addr, int offset, u8 val)
> >> +{
> >> + u32 val32 = readl(addr + (offset & ~0x3));
> >> +
> >> + switch (offset & 0x3) {
> >> + case 0:
> >> + val32 &= ~0xFF;
> >> + val32 |= val;
> >> + break;
> >> + case 1:
> >> + val32 &= ~0xFF00;
> >> + val32 |= (u32)val << 8;
> >> + break;
> >> + case 2:
> >> + val32 &= ~0xFF0000;
> >> + val32 |= (u32)val << 16;
> >> + break;
> >> + case 3:
> >> + default:
> >> + val32 &= ~0xFF000000;
> >> + val32 |= (u32)val << 24;
> >> + break;
> >> + }
> >> + writel(val32, addr + (offset & ~0x3));
> >> +}
> >> +
> >> +static inline void xgene_pcie_cfg_in32(void __iomem *addr, int offset, u32 *val)
> >> +{
> >> + *val = readl(addr + offset);
> >> +}
> >> +
> >> +static inline void
> >> +xgene_pcie_cfg_in16(void __iomem *addr, int offset, u32 *val)
> >> +{
> >> + *val = readl(addr + (offset & ~0x3));
> >> +
> >> + switch (offset & 0x3) {
> >> + case 2:
> >> + *val >>= 16;
> >> + break;
> >> + }
> >> +
> >> + *val &= 0xFFFF;
> >> +}
> >> +
> >> +static inline void
> >> +xgene_pcie_cfg_in8(void __iomem *addr, int offset, u32 *val)
> >> +{
> >> + *val = readl(addr + (offset & ~0x3));
> >> +
> >> + switch (offset & 0x3) {
> >> + case 3:
> >> + *val = *val >> 24;
> >> + break;
> >> + case 2:
> >> + *val = *val >> 16;
> >> + break;
> >> + case 1:
> >> + *val = *val >> 8;
> >> + break;
> >> + }
> >> + *val &= 0xFF;
> >> +}
> >> +
> >> +/* When the address bit [17:16] is 2'b01, the Configuration access will be
> >> + * treated as Type 1 and it will be forwarded to external PCIe device.
> >> + */
> >> +static void __iomem *xgene_pcie_get_cfg_base(struct pci_bus *bus)
> >> +{
> >> + struct xgene_pcie_port *port = bus->sysdata;
> >> +
> >> + if (bus->number >= (bus->primary + 1))
> >
> > I fail to see the link between what the comment says and what the code does. It
> > looks to me like any bus with a number from bus->primary +1 onwards will have
> > it's cfg_base altered. How does that translate into address bits?
>
> I think the problem is with my comment. It should be 'When the address
> bit [17:16] is 2'b01, the Configuration access will be treated as Type
> _0_' . Cfg region for type 0 gets mapped 64K offset from the cfg base.
> 'xgene_pcie_set_rtdid_reg' selects which b.d.f to be mapped. We don't
> have ECAM supported in this SOC.

Yes, that is much clearer and I now understand the offsetting of the cfg_base. Thanks!

>
> >
> >> + return port->cfg_base + AXI_EP_CFG_ACCESS;
> >> +
> >> + return port->cfg_base;
> >> +}
> >> +
> >> +/* For Configuration request, RTDID register is used as Bus Number,
> >> + * Device Number and Function number of the header fields.
> >> + */
> >> +static void xgene_pcie_set_rtdid_reg(struct pci_bus *bus, uint devfn)
> >> +{
> >> + struct xgene_pcie_port *port = bus->sysdata;
> >> + unsigned int b, d, f;
> >> + u32 rtdid_val = 0;
> >> +
> >> + b = bus->number;
> >> + d = PCI_SLOT(devfn);
> >> + f = PCI_FUNC(devfn);
> >> +
> >> + if (!pci_is_root_bus(bus))
> >> + rtdid_val = (b << 8) | (d << 3) | f;
> >> +
> >> + writel(rtdid_val, port->csr_base + RTDID);
> >> + /* read the register back to ensure flush */
> >> + readl(port->csr_base + RTDID);
> >> +}
> >> +
> >> +static int xgene_pcie_read_config(struct pci_bus *bus, unsigned int devfn,
> >> + int offset, int len, u32 *val)
> >> +{
> >> + struct xgene_pcie_port *port = bus->sysdata;
> >> + void __iomem *addr;
> >> +
> >> + if ((pci_is_root_bus(bus) && devfn != 0) || !port->link_up)
> >> + return PCIBIOS_DEVICE_NOT_FOUND;
> >> +
> >> + xgene_pcie_set_rtdid_reg(bus, devfn);
> >> + addr = xgene_pcie_get_cfg_base(bus);
> >> + switch (len) {
> >> + case 1:
> >> + xgene_pcie_cfg_in8(addr, offset, val);
> >> + break;
> >> + case 2:
> >> + xgene_pcie_cfg_in16(addr, offset, val);
> >> + break;
> >> + default:
> >> + xgene_pcie_cfg_in32(addr, offset, val);
> >> + break;
> >> + }
> >> + return PCIBIOS_SUCCESSFUL;
> >> +}
> >> +
> >> +static int xgene_pcie_write_config(struct pci_bus *bus, unsigned int devfn,
> >> + int offset, int len, u32 val)
> >> +{
> >> + struct xgene_pcie_port *port = bus->sysdata;
> >> + void __iomem *addr;
> >> +
> >> + if ((pci_is_root_bus(bus) && devfn != 0) || !port->link_up)
> >> + return PCIBIOS_DEVICE_NOT_FOUND;
> >> +
> >> + xgene_pcie_set_rtdid_reg(bus, devfn);
> >> + addr = xgene_pcie_get_cfg_base(bus);
> >> + switch (len) {
> >> + case 1:
> >> + xgene_pcie_cfg_out8(addr, offset, (u8)val);
> >> + break;
> >> + case 2:
> >> + xgene_pcie_cfg_out16(addr, offset, (u16)val);
> >> + break;
> >> + default:
> >> + xgene_pcie_cfg_out32(addr, offset, val);
> >> + break;
> >> + }
> >> + return PCIBIOS_SUCCESSFUL;
> >> +}
> >> +
> >> +static struct pci_ops xgene_pcie_ops = {
> >> + .read = xgene_pcie_read_config,
> >> + .write = xgene_pcie_write_config
> >> +};
> >> +
> >> +static void xgene_pcie_program_core(void __iomem *csr_base)
> >> +{
> >> + u32 val;
> >> +
> >> + val = readl(csr_base + BRIDGE_CFG_0);
> >> + val |= AER_OPTIONAL_ERROR_EN;
> >> + writel(val, csr_base + BRIDGE_CFG_0);
> >> + writel(0x0, csr_base + INTXSTATUSMASK);
> >> + val = readl(csr_base + BRIDGE_CTRL_1);
> >> + val = (val & ~0xffff) | XGENE_PCIE_DEV_CTRL;
> >> + writel(val, csr_base + BRIDGE_CTRL_1);
> >> +}
> >> +
> >> +static u64 xgene_pcie_set_ib_mask(void __iomem *csr_base, u32 addr,
> >> + u32 flags, u64 size)
> >> +{
> >> + u64 mask = (~(size - 1) & PCI_BASE_ADDRESS_MEM_MASK) | flags;
> >> + u32 val32 = 0;
> >> + u32 val;
> >> +
> >> + val32 = readl(csr_base + addr);
> >> + val = (val32 & 0x0000ffff) | (lower_32_bits(mask) << 16);
> >> + writel(val, csr_base + addr);
> >> +
> >> + val32 = readl(csr_base + addr + 0x04);
> >> + val = (val32 & 0xffff0000) | (lower_32_bits(mask) >> 16);
> >> + writel(val, csr_base + addr + 0x04);
> >> +
> >> + val32 = readl(csr_base + addr + 0x04);
> >> + val = (val32 & 0x0000ffff) | (upper_32_bits(mask) << 16);
> >> + writel(val, csr_base + addr + 0x04);
> >> +
> >> + val32 = readl(csr_base + addr + 0x08);
> >> + val = (val32 & 0xffff0000) | (upper_32_bits(mask) >> 16);
> >> + writel(val, csr_base + addr + 0x08);
> >> +
> >> + return mask;
> >> +}
> >> +
> >> +static void xgene_pcie_poll_linkup(struct xgene_pcie_port *port,
> >> + u32 *lanes, u32 *speed)
> >> +{
> >> + void __iomem *csr_base = port->csr_base;
> >> + ulong timeout;
> >> + u32 val32;
> >> +
> >> + /*
> >> + * A component enters the LTSSM Detect state within
> >> + * 20ms of the end of fundamental core reset.
> >> + */
> >> + msleep(XGENE_LTSSM_DETECT_WAIT);
> >> + port->link_up = 0;
> >> + timeout = jiffies + msecs_to_jiffies(XGENE_LTSSM_L0_WAIT);
> >> + while (time_before(jiffies, timeout)) {
> >> + val32 = readl(csr_base + PCIECORE_CTLANDSTATUS);
> >> + if (val32 & LINK_UP_MASK) {
> >> + port->link_up = 1;
> >> + *speed = PIPE_PHY_RATE_RD(val32);
> >> + val32 = readl(csr_base + BRIDGE_STATUS_0);
> >> + *lanes = val32 >> 26;
> >> + break;
> >> + }
> >> + msleep(1);
> >> + }
> >> +}
> >> +
> >> +static void xgene_pcie_setup_root_complex(struct xgene_pcie_port *port)
> >> +{
> >> + void __iomem *csr_base = port->csr_base;
> >> + u32 val;
> >> +
> >> + val = (XGENE_PCIE_DEVICEID << 16) | XGENE_PCIE_VENDORID;
> >> + writel(val, csr_base + BRIDGE_CFG_0);
> >> +
> >> + val = readl(csr_base + BRIDGE_CFG_1);
> >> + val &= ~CLASS_CODE_MASK;
> >> + val |= PCI_CLASS_BRIDGE_PCI << 16;
> >> + writel(val, csr_base + BRIDGE_CFG_1);
> >> +
> >> + val = readl(csr_base + BRIDGE_CFG_14);
> >> + val |= SWITCH_PORT_MODE_MASK;
> >> + val &= ~PM_FORCE_RP_MODE_MASK;
> >> + writel(val, csr_base + BRIDGE_CFG_14);
> >> +
> >> + val = readl(csr_base + BRIDGE_CTRL_5);
> >> + val &= ~DEVICE_PORT_TYPE_MASK;
> >> + val |= XGENE_PORT_TYPE_RC;
> >> + writel(val, csr_base + BRIDGE_CTRL_5);
> >> +
> >> + val = readl(csr_base + BRIDGE_CTRL_2);
> >> + val |= ENABLE_ASPM;
> >> + writel(val, csr_base + BRIDGE_CTRL_2);
> >> +
> >> + val = readl(csr_base + BRIDGE_CFG_32);
> >> + writel(val | (1 << 19), csr_base + BRIDGE_CFG_32);
> >> +}
> >> +
> >> +/* Return 0 on success */
> >
> > Comment is not very helpful, this is supposed to be the default behaviour
> > in kernel code.
>
> Got it.
> >
> >> +static int xgene_pcie_init_ecc(struct xgene_pcie_port *port)
> >> +{
> >> + void __iomem *csr_base = port->csr_base;
> >> + ulong timeout;
> >> + u32 val;
> >> +
> >> + val = readl(csr_base + MEM_RAM_SHUTDOWN);
> >> + if (!val)
> >> + return 0;
> >> + writel(0x0, csr_base + MEM_RAM_SHUTDOWN);
> >> + timeout = jiffies + msecs_to_jiffies(XGENE_PCIE_ECC_TIMEOUT);
> >> + while (time_before(jiffies, timeout)) {
> >> + val = readl(csr_base + BLOCK_MEM_RDY);
> >> + if (val == BLOCK_MEM_RDY_VAL)
> >> + return 0;
> >> + msleep(1);
> >> + }
> >> +
> >
> > Maybe add a comment here suggesting this is the error return. Better yet,
> > use the kernel convention of returning negative numbers for errors and
> > use one of the errno-base.h values.
>
> Yes. How about '-EBUSY'?

Looks like a sensible return value.

>
> >
> >> + return 1;
> >> +}
> >> +
> >> +static int xgene_pcie_init_port(struct xgene_pcie_port *port)
> >> +{
> >> + int rc;
> >> +
> >> + port->clk = clk_get(port->dev, NULL);
> >> + if (IS_ERR(port->clk)) {
> >> + dev_err(port->dev, "clock not available\n");
> >> + return -ENODEV;
> >> + }
> >> +
> >> + rc = clk_prepare_enable(port->clk);
> >> + if (rc) {
> >> + dev_err(port->dev, "clock enable failed\n");
> >> + return rc;
> >> + }
> >> +
> >> + rc = xgene_pcie_init_ecc(port);
> >> + if (rc) {
> >> + dev_err(port->dev, "memory init failed\n");
> >> + return rc;
> >> + }
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static void xgene_pcie_fixup_bridge(struct pci_dev *dev)
> >> +{
> >> + int i;
> >> +
> >> + /* Hide the PCI host BARs from the kernel as their content doesn't
> >> + * fit well in the resource management
> >> + */
> >> + for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
> >> + dev->resource[i].start = dev->resource[i].end = 0;
> >> + dev->resource[i].flags = 0;
> >> + }
> >> + dev_info(&dev->dev, "Hiding X-Gene pci host bridge resources %s\n",
> >> + pci_name(dev));
> >> +}
> >> +DECLARE_PCI_FIXUP_HEADER(XGENE_PCIE_VENDORID, XGENE_PCIE_DEVICEID,
> >> + xgene_pcie_fixup_bridge);
> >> +
> >> +static int xgene_pcie_map_reg(struct xgene_pcie_port *port,
> >> + struct platform_device *pdev, u64 *cfg_addr)
> >> +{
> >> + struct resource *res;
> >> +
> >> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "csr");
> >> + port->csr_base = devm_ioremap_resource(port->dev, res);
> >> + if (IS_ERR(port->csr_base))
> >> + return PTR_ERR(port->csr_base);
> >> +
> >> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cfg");
> >> + port->cfg_base = devm_ioremap_resource(port->dev, res);
> >> + if (IS_ERR(port->cfg_base))
> >> + return PTR_ERR(port->cfg_base);
> >> + *cfg_addr = res->start;
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static void xgene_pcie_setup_ob_reg(struct xgene_pcie_port *port,
> >> + struct resource *res, u32 offset, u64 addr)
> >> +{
> >> + void __iomem *base = port->csr_base + offset;
> >> + resource_size_t size = resource_size(res);
> >> + u64 restype = resource_type(res);
> >> + u64 cpu_addr, pci_addr;
> >> + u64 mask = 0;
> >> + u32 min_size;
> >> + u32 flag = EN_REG;
> >> +
> >> + if (restype == IORESOURCE_MEM) {
> >> + cpu_addr = res->start;
> >> + pci_addr = addr;
> >> + min_size = SZ_128M;
> >> + } else {
> >> + cpu_addr = addr;
> >> + pci_addr = res->start;
> >> + min_size = 128;
> >> + flag |= OB_LO_IO;
> >> + }
> >> + if (size >= min_size)
> >> + mask = ~(size - 1) | flag;
> >> + else
> >> + dev_warn(port->dev, "res size 0x%llx less than minimum 0x%x\n",
> >> + (u64)size, min_size);
> >> + writel(lower_32_bits(cpu_addr), base);
> >> + writel(upper_32_bits(cpu_addr), base + 0x04);
> >> + writel(lower_32_bits(mask), base + 0x08);
> >> + writel(upper_32_bits(mask), base + 0x0c);
> >> + writel(lower_32_bits(pci_addr), base + 0x10);
> >> + writel(upper_32_bits(pci_addr), base + 0x14);
> >> +}
> >> +
> >> +static void xgene_pcie_setup_cfg_reg(void __iomem *csr_base, u64 addr)
> >> +{
> >> + writel(lower_32_bits(addr), csr_base + CFGBARL);
> >> + writel(upper_32_bits(addr), csr_base + CFGBARH);
> >> + writel(EN_REG, csr_base + CFGCTL);
> >> +}
> >> +
> >> +static int xgene_pcie_map_ranges(struct xgene_pcie_port *port,
> >> + struct pci_host_bridge *bridge,
> >> + u64 cfg_addr)
> >> +{
> >> + struct device *dev = port->dev;
> >> + struct pci_host_bridge_window *window;
> >> + int ret;
> >> +
> >> + list_for_each_entry(window, &bridge->windows, list) {
> >> + struct resource *res = window->res;
> >> + u64 restype = resource_type(res);
> >> + dev_dbg(port->dev, "0x%08lx 0x%016llx...0x%016llx\n",
> >> + res->flags, res->start, res->end);
> >> +
> >> + switch (restype) {
> >> + case IORESOURCE_IO:
> >> + xgene_pcie_setup_ob_reg(port, res, OMR2BARL,
> >> + bridge->io_base);
> >> + ret = pci_ioremap_io(res, bridge->io_base);
> >> + if (ret < 0)
> >> + return ret;
> >> + break;
> >> + case IORESOURCE_MEM:
> >> + xgene_pcie_setup_ob_reg(port, res, OMR3BARL,
> >> + res->start - window->offset);
> >> + break;
> >> + case IORESOURCE_BUS:
> >> + break;
> >> + default:
> >> + dev_err(dev, "invalid io resource!");
> >> + return -EINVAL;
> >> + }
> >> + }
> >> + xgene_pcie_setup_cfg_reg(port->csr_base, cfg_addr);
> >> + return 0;
> >> +}
> >> +
> >> +static void xgene_pcie_setup_pims(void *addr, u64 pim, u64 size)
> >> +{
> >> + writel(lower_32_bits(pim), addr);
> >> + writel(upper_32_bits(pim) | EN_COHERENCY, addr + 0x04);
> >> + writel(lower_32_bits(size), addr + 0x10);
> >> + writel(upper_32_bits(size), addr + 0x14);
> >> +}
> >> +
> >> +/*
> >> + * X-Gene PCIe support maximum 3 inbound memory regions
> >> + * This function helps to select a region based on size of region
> >> + */
> >> +static int xgene_pcie_select_ib_reg(u8 *ib_reg_mask, u64 size)
> >> +{
> >> + if ((size > 4) && (size < SZ_16M) && !(*ib_reg_mask & (1 << 1))) {
> >> + *ib_reg_mask |= (1 << 1);
> >> + return 1;
> >> + }
> >> +
> >> + if ((size > SZ_1K) && (size < SZ_1T) && !(*ib_reg_mask & (1 << 0))) {
> >> + *ib_reg_mask |= (1 << 0);
> >> + return 0;
> >> + }
> >> +
> >> + if ((size > SZ_1M) && (size < SZ_1T) && !(*ib_reg_mask & (1 << 2))) {
> >> + *ib_reg_mask |= (1 << 2);
> >> + return 2;
> >> + }
> >> + return -EINVAL;
> >> +}
> >> +
> >> +static void xgene_pcie_setup_ib_reg(struct xgene_pcie_port *port,
> >> + struct of_pci_range *range, u8 *ib_reg_mask)
> >> +{
> >> + void __iomem *csr_base = port->csr_base;
> >> + void __iomem *cfg_base = port->cfg_base;
> >> + void *bar_addr;
> >> + void *pim_addr;
> >> + u64 restype = range->flags & IORESOURCE_TYPE_BITS;
> >> + u64 cpu_addr = range->cpu_addr;
> >> + u64 pci_addr = range->pci_addr;
> >> + u64 size = range->size;
> >> + u64 mask = ~(size - 1) | EN_REG;
> >> + u32 flags = PCI_BASE_ADDRESS_MEM_TYPE_64;
> >> + u32 bar_low;
> >> + int region;
> >> +
> >> + region = xgene_pcie_select_ib_reg(ib_reg_mask, range->size);
> >> + if (region < 0) {
> >> + dev_warn(port->dev, "invalid pcie dma-range config\n");
> >> + return;
> >> + }
> >> +
> >> + if (restype == PCI_BASE_ADDRESS_MEM_PREFETCH)
> >> + flags |= PCI_BASE_ADDRESS_MEM_PREFETCH;
> >> +
> >> + bar_low = pcie_bar_low_val((u32)cpu_addr, flags);
> >> + switch (region) {
> >> + case 0:
> >> + xgene_pcie_set_ib_mask(csr_base, BRIDGE_CFG_4, flags, size);
> >> + bar_addr = cfg_base + PCI_BASE_ADDRESS_0;
> >> + writel(bar_low, bar_addr);
> >> + writel(upper_32_bits(cpu_addr), bar_addr + 0x4);
> >> + pim_addr = csr_base + PIM1_1L;
> >> + break;
> >> + case 1:
> >> + bar_addr = csr_base + IBAR2;
> >> + writel(bar_low, bar_addr);
> >> + writel(lower_32_bits(mask), csr_base + IR2MSK);
> >> + pim_addr = csr_base + PIM2_1L;
> >> + break;
> >> + case 2:
> >> + bar_addr = csr_base + IBAR3L;
> >> + writel(bar_low, bar_addr);
> >> + writel(upper_32_bits(cpu_addr), bar_addr + 0x4);
> >> + writel(lower_32_bits(mask), csr_base + IR3MSKL);
> >> + writel(upper_32_bits(mask), csr_base + IR3MSKL + 0x4);
> >> + pim_addr = csr_base + PIM3_1L;
> >> + break;
> >> + }
> >> +
> >> + xgene_pcie_setup_pims(pim_addr, pci_addr, size);
> >> +}
> >> +
> >> +static int pci_dma_range_parser_init(struct of_pci_range_parser *parser,
> >> + struct device_node *node)
> >> +{
> >> + const int na = 3, ns = 2;
> >> + int rlen;
> >> +
> >> + parser->node = node;
> >> + parser->pna = of_n_addr_cells(node);
> >> + parser->np = parser->pna + na + ns;
> >> +
> >> + parser->range = of_get_property(node, "dma-ranges", &rlen);
> >> + if (!parser->range)
> >> + return -ENOENT;
> >> +
> >> + parser->end = parser->range + rlen / sizeof(__be32);
> >> + return 0;
> >> +}
> >> +
> >> +static int xgene_pcie_parse_map_dma_ranges(struct xgene_pcie_port *port)
> >> +{
> >> + struct device_node *np = port->node;
> >> + struct of_pci_range range;
> >> + struct of_pci_range_parser parser;
> >> + struct device *dev = port->dev;
> >> + u8 ib_reg_mask = 0;
> >> +
> >> + if (pci_dma_range_parser_init(&parser, np)) {
> >> + dev_err(dev, "missing dma-ranges property\n");
> >> + return -EINVAL;
> >> + }
> >> +
> >> + /* Get the dma-ranges from DT */
> >> + for_each_of_pci_range(&parser, &range) {
> >> + u64 end = range.cpu_addr + range.size - 1;
> >> + dev_dbg(port->dev, "0x%08x 0x%016llx..0x%016llx -> 0x%016llx\n",
> >> + range.flags, range.cpu_addr, end, range.pci_addr);
> >> + xgene_pcie_setup_ib_reg(port, &range, &ib_reg_mask);
> >> + }
> >> + return 0;
> >> +}
> >> +
> >> +static int xgene_pcie_probe_bridge(struct platform_device *pdev)
> >> +{
> >> + struct device_node *np = of_node_get(pdev->dev.of_node);
> >> + struct xgene_pcie_port *port;
> >> + struct pci_host_bridge *bridge;
> >> + resource_size_t lastbus;
> >> + u32 lanes = 0, speed = 0;
> >> + u64 cfg_addr = 0;
> >> + int ret;
> >> +
> >> + port = devm_kzalloc(&pdev->dev, sizeof(*port), GFP_KERNEL);
> >> + if (!port)
> >> + return -ENOMEM;
> >> + port->node = np;
> >> + port->dev = &pdev->dev;
> >> +
> >> + ret = xgene_pcie_map_reg(port, pdev, &cfg_addr);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + ret = xgene_pcie_init_port(port);
> >> + if (ret)
> >> + return ret;
> >> + xgene_pcie_program_core(port->csr_base);
> >> + xgene_pcie_setup_root_complex(port);
> >> +
> >> + bridge = of_create_pci_host_bridge(&pdev->dev, &xgene_pcie_ops, port);
> >> + if (IS_ERR_OR_NULL(bridge))
> >
> > If bridge is NULL (can't see how in my code, but anyway)
> >
> >> + return PTR_ERR(bridge);
> >
> > Then this will return zero (i.e. success).
> >
> > s/IS_ERR_OR_NULL/IS_ERR/g
> >
>
> Thanks. I should have fixed it earlier after Arnd's comment.
>
> >> +
> >> + ret = xgene_pcie_map_ranges(port, bridge, cfg_addr);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + ret = xgene_pcie_parse_map_dma_ranges(port);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + xgene_pcie_poll_linkup(port, &lanes, &speed);
> >> + if (!port->link_up)
> >> + dev_info(port->dev, "(rc) link down\n");
> >> + else
> >> + dev_info(port->dev, "(rc) x%d gen-%d link up\n",
> >> + lanes, speed + 1);
> >> + platform_set_drvdata(pdev, port);
> >> + lastbus = pci_rescan_bus(bridge->bus);
> >
> > If you look in drivers/pci/probe.c *after* the definition of pci_rescan_bus()
> > there is a comment about the function needing to be guarded by
> > pci_lock_rescan_remove() and pci_unlock_rescan_remove(). The only one doing
> > it is drivers/pci/pci-sysfs.c, while s390 seems oblivious to it.
>
> The only purpose of using pci_rescan_bus here is that it combines all
> the APIs required to scan the bus in current implementation. This will
> be invoked during boot time. Do we need mutexes at that time? IMO
> mutexes will be helpful in hotplug kind of situation.

You might be right, but I think for future proofing your code it makes sense
to add the lock guard. Think about a future system where you have two host
controllers, a more recent one and this as a legacy fallback that only gets
instantiated if certain conditions are met. It is feasible to image that while
you are probing this host controller you might be removing busses from the
new fancy host controller to add them here as 'legacy', in which case the
framework is going to be really stroppy.

Best regards,
Liviu

> >
> >> + pci_bus_update_busn_res_end(bridge->bus, lastbus);
> >> + return 0;
> >> +}
> >> +
> >> +static const struct of_device_id xgene_pcie_match_table[] = {
> >> + {.compatible = "apm,xgene-pcie",},
> >> + {},
> >> +};
> >> +
> >> +static struct platform_driver xgene_pcie_driver = {
> >> + .driver = {
> >> + .name = "xgene-pcie",
> >> + .owner = THIS_MODULE,
> >> + .of_match_table = of_match_ptr(xgene_pcie_match_table),
> >> + },
> >> + .probe = xgene_pcie_probe_bridge,
> >> +};
> >> +module_platform_driver(xgene_pcie_driver);
> >> +
> >> +MODULE_AUTHOR("Tanmay Inamdar <tinamdar@xxxxxxx>");
> >> +MODULE_DESCRIPTION("APM X-Gene PCIe driver");
> >> +MODULE_LICENSE("GPL v2");
> >> --
> >> 1.7.9.5
> >>
> >>

--
====================
| I would like to |
| fix the world, |
| but they're not |
| giving me the |
\ source code! /
---------------
Â\_(ã)_/Â

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