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Date: Thu, 14 Jul 2016 20:00:59 -0400
From: Paul Gortmaker <paul.gortmaker@...driver.com>
To: Tan Jui Nee <jui.nee.tan@...el.com>
Cc: mika.westerberg@...ux.intel.com, heikki.krogerus@...ux.intel.com,
andriy.shevchenko@...ux.intel.com,
"tglx@...utronix.de" <tglx@...utronix.de>, mingo@...hat.com,
"H. Peter Anvin" <hpa@...or.com>, X86 ML <x86@...nel.org>,
ptyser@...-inc.com, Lee Jones <lee.jones@...aro.org>,
Linus Walleij <linus.walleij@...aro.org>,
linux-gpio@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
jonathan.yong@...el.com, ong.hock.yu@...el.com,
weifeng.voon@...el.com, wan.ahmad.zainie.wan.mohamad@...el.com
Subject: Re: [PATCH v6 1/3] x86/platform/p2sb: New Primary to Sideband bridge
support driver for Intel SOC's
On Thu, Jul 14, 2016 at 4:11 AM, Tan Jui Nee <jui.nee.tan@...el.com> wrote:
> From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
>
> There is already one and at least one more user coming which
> require an access to Primary to Sideband bridge (P2SB) in order
> to get IO or MMIO bar hidden by BIOS.
> Create a driver to access P2SB for x86 devices.
>
> Signed-off-by: Yong, Jonathan <jonathan.yong@...el.com>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> ---
> Changes in V6:
> - No change
>
> Changes in V5:
> - No change
>
> Changes in V4:
> - Move Kconfig option CONFIG_X86_INTEL_NON_ACPI from
> [PATCH 2/3] x86/platform/p2sb: New Primary to Sideband bridge support driver for Intel SOC's
> to
> [PATCH 3/3] mfd: lpc_ich: Add support for Intel Apollo Lake GPIO pinctrl in non-ACPI system
> since the config is used in latter patch.
>
> Changes in V3:
> - No change
>
> Changes in V2:
> - Add new config option CONFIG_X86_INTEL_NON_ACPI and "select PINCTRL"
> to fix kbuildbot error
>
> arch/x86/Kconfig | 4 ++
> arch/x86/include/asm/p2sb.h | 27 +++++++++++
> arch/x86/platform/intel/Makefile | 1 +
> arch/x86/platform/intel/p2sb.c | 99 ++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 131 insertions(+)
> create mode 100644 arch/x86/include/asm/p2sb.h
> create mode 100644 arch/x86/platform/intel/p2sb.c
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index d9a94da..d305d81 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -604,6 +604,10 @@ config IOSF_MBI_DEBUG
>
> If you don't require the option or are in doubt, say N.
>
> +config P2SB
> + tristate
OK, this is tristate, but then....
> + depends on PCI
> +
> config X86_RDC321X
> bool "RDC R-321x SoC"
> depends on X86_32
> diff --git a/arch/x86/include/asm/p2sb.h b/arch/x86/include/asm/p2sb.h
> new file mode 100644
> index 0000000..686e07b
> --- /dev/null
> +++ b/arch/x86/include/asm/p2sb.h
> @@ -0,0 +1,27 @@
> +/*
> + * Primary to Sideband bridge (P2SB) access support
> + */
> +
> +#ifndef P2SB_SYMS_H
> +#define P2SB_SYMS_H
> +
> +#include <linux/ioport.h>
> +#include <linux/pci.h>
> +
> +#if IS_ENABLED(CONFIG_P2SB)
> +
> +int p2sb_bar(struct pci_dev *pdev, unsigned int devfn,
> + struct resource *res);
> +
> +#else /* CONFIG_P2SB is not set */
> +
> +static inline
> +int p2sb_bar(struct pci_dev *pdev, unsigned int devfn,
> + struct resource *res)
> +{
> + return -ENODEV;
> +}
> +
> +#endif /* CONFIG_P2SB */
> +
> +#endif /* P2SB_SYMS_H */
> diff --git a/arch/x86/platform/intel/Makefile b/arch/x86/platform/intel/Makefile
> index b878032..dbf9f10 100644
> --- a/arch/x86/platform/intel/Makefile
> +++ b/arch/x86/platform/intel/Makefile
> @@ -1 +1,2 @@
> obj-$(CONFIG_IOSF_MBI) += iosf_mbi.o
> +obj-$(CONFIG_P2SB) += p2sb.o
> diff --git a/arch/x86/platform/intel/p2sb.c b/arch/x86/platform/intel/p2sb.c
> new file mode 100644
> index 0000000..8be47a4
> --- /dev/null
> +++ b/arch/x86/platform/intel/p2sb.c
> @@ -0,0 +1,99 @@
> +/*
> + * Primary to Sideband bridge (P2SB) driver
> + *
> + * Copyright (c) 2016, Intel Corporation.
> + *
> + * Authors: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> + * Jonathan Yong <jonathan.yong@...el.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope 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/ioport.h>
> +#include <linux/module.h>
...and module.h is included, but yet...
> +#include <linux/pci.h>
> +#include <linux/spinlock.h>
> +
> +#include <asm/p2sb.h>
> +
> +#define SBREG_BAR 0x10
> +#define SBREG_HIDE 0xe1
> +
> +static DEFINE_SPINLOCK(p2sb_spinlock);
> +
> +/*
> + * p2sb_bar - Get Primary to Sideband bridge (P2SB) BAR
> + * @pdev: PCI device to get PCI bus to communicate with
> + * @devfn: PCI device and function to communicate with
> + * @res: resources to be filled in
> + *
> + * The BIOS prevents the P2SB device from being enumerated by the PCI
> + * subsystem, so we need to unhide and hide it back to lookup the P2SB BAR.
> + *
> + * Locking is handled by spinlock - cannot sleep.
> + *
> + * Return:
> + * 0 on success or appropriate errno value on error.
> + */
> +int p2sb_bar(struct pci_dev *pdev, unsigned int devfn,
> + struct resource *res)
> +{
> + u32 base_addr;
> + u64 base64_addr;
> + unsigned long flags;
> +
> + if (!res)
> + return -EINVAL;
> +
> + spin_lock(&p2sb_spinlock);
> +
> + /* Unhide the P2SB device */
> + pci_bus_write_config_byte(pdev->bus, devfn, SBREG_HIDE, 0x00);
> +
> + /* Check if device present */
> + pci_bus_read_config_dword(pdev->bus, devfn, 0, &base_addr);
> + if (base_addr == 0xffffffff || base_addr == 0x00000000) {
> + spin_unlock(&p2sb_spinlock);
> + dev_warn(&pdev->dev, "P2SB device access disabled by BIOS?\n");
> + return -ENODEV;
> + }
> +
> + /* Get IO or MMIO BAR */
> + pci_bus_read_config_dword(pdev->bus, devfn, SBREG_BAR, &base_addr);
> + if ((base_addr & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_IO) {
> + flags = IORESOURCE_IO;
> + base64_addr = base_addr & PCI_BASE_ADDRESS_IO_MASK;
> + } else {
> + flags = IORESOURCE_MEM;
> + base64_addr = base_addr & PCI_BASE_ADDRESS_MEM_MASK;
> + if (base_addr & PCI_BASE_ADDRESS_MEM_TYPE_64) {
> + flags |= IORESOURCE_MEM_64;
> + pci_bus_read_config_dword(pdev->bus, devfn,
> + SBREG_BAR + 4, &base_addr);
> + base64_addr |= (u64)base_addr << 32;
> + }
> + }
> +
> + /* Hide the P2SB device */
> + pci_bus_write_config_byte(pdev->bus, devfn, SBREG_HIDE, 0x01);
> +
> + spin_unlock(&p2sb_spinlock);
> +
> + /* User provides prefilled resources */
> + res->start += (resource_size_t)base64_addr;
> + res->end += (resource_size_t)base64_addr;
> + res->flags = flags;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(p2sb_bar);
> +
> +MODULE_LICENSE("GPL");
...the above is the only modular "use" that I can find. So is the
tristate bogus? Without a module_init and a module_exit I am
confused....
I just finished an audit of arch/x86 for bogus uses of module.h
so I'd like to ensure we don't add more.
Thanks,
Paul.
--
> --
> 1.9.1
>
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