Message-ID: <20161109113955.GD10219@e106497-lin.cambridge.arm.com>
Date:   Wed, 9 Nov 2016 11:39:55 +0000
From:   liviu.dudau@....com
To:     "zhichang.yuan" <yuanzhichang@...ilicon.com>
Cc:     catalin.marinas@....com, will.deacon@....com, robh+dt@...nel.org,
        bhelgaas@...gle.com, mark.rutland@....com, olof@...om.net,
        arnd@...db.de, linux-arm-kernel@...ts.infradead.org,
        lorenzo.pieralisi@....com, linux-kernel@...r.kernel.org,
        linuxarm@...wei.com, devicetree@...r.kernel.org,
        linux-pci@...r.kernel.org, linux-serial@...r.kernel.org,
        minyard@....org, benh@...nel.crashing.org, zourongrong@...il.com,
        john.garry@...wei.com, gabriele.paoloni@...wei.com,
        zhichang.yuan02@...il.com, kantyzc@....com, xuwei5@...ilicon.com
Subject: Re: [PATCH V5 2/3] ARM64 LPC: Add missing range exception for
 special ISA

On Tue, Nov 08, 2016 at 11:47:08AM +0800, zhichang.yuan wrote:
> This patch solves two issues:
> 1) parse and get the right I/O range from DTS node whose parent does not
> define the corresponding ranges property;
> 
> There are some special ISA/LPC devices that work on a specific I/O range where
> it is not correct to specify a ranges property in DTS parent node as cpu
> addresses translated from DTS node are only for memory space on some
> architectures, such as Arm64. Without the parent 'ranges' property, current
> of_translate_address() return an error.
> Here we add a fixup function, of_get_isa_indirect_io(). During the OF address
> translation, this fixup will be called to check the 'reg' address to be
> translating is for those sepcial ISA/LPC devices and get the I/O range
> directly from the 'reg' property.
> 
> 2) eliminate the I/O range conflict risk with PCI/PCIE leagecy I/O device;
> 
> The current __of_address_to_resource() always translates the I/O range to PIO.
> But this processing is not suitable for our ISA/LPC devices whose I/O range is
> not cpu address(Arnd had stressed this in his comments on V2,V3 patch-set).
> Here, we bypass the mapping between cpu address and PIO for the special
> ISA/LPC devices. But to drive these ISA/LPC devices, a I/O port address below
> PCIBIOS_MIN_IO is needed by in*/out*(). Which means there is conflict risk
> between I/O range of [0, PCIBIOS_MIN_IO) and PCI/PCIE legacy I/O range of [0,
> IO_SPACE_LIMIT).
> To avoid the I/O conflict, this patch reserve the I/O range below
> PCIBIOS_MIN_IO.
> 
> Signed-off-by: zhichang.yuan <yuanzhichang@...ilicon.com>
> Signed-off-by: Gabriele Paoloni <gabriele.paoloni@...wei.com>
> ---
>  .../arm/hisilicon/hisilicon-low-pin-count.txt      | 31 ++++++++++++
>  arch/arm64/include/asm/io.h                        |  6 +++
>  arch/arm64/kernel/extio.c                          | 25 ++++++++++
>  drivers/of/address.c                               | 56 +++++++++++++++++++++-
>  drivers/pci/pci.c                                  |  6 +--
>  include/linux/of_address.h                         | 17 +++++++
>  include/linux/pci.h                                |  8 ++++
>  7 files changed, 145 insertions(+), 4 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt
> 
> diff --git a/Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt b/Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt
> new file mode 100644
> index 0000000..13c8ddd
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/hisilicon/hisilicon-low-pin-count.txt
> @@ -0,0 +1,31 @@
> +Hisilicon Hip06 low-pin-count device
> +  Usually LPC controller is part of PCI host bridge, so the legacy ISA ports
> +  locate on LPC bus can be accessed direclty. But some SoCs have independent
> +  LPC controller, and access the legacy ports by triggering LPC I/O cycles.
> +  Hisilicon Hip06 implements this LPC device.
> +
> +Required properties:
> +- compatible: should be "hisilicon,low-pin-count"
> +- #address-cells: must be 2 which stick to the ISA/EISA binding doc.
> +- #size-cells: must be 1 which stick to the ISA/EISA binding doc.
> +- reg: base memory range where the register set of this device is mapped.
> +
> +Note:
> +  The node name before '@' must be "isa" to represent the binding stick to the
> +  ISA/EISA binding specification.
> +
> +Example:
> +
> +isa@...b0000 {
> +	compatible = "hisilicom,low-pin-count";
> +	#address-cells = <2>;
> +	#size-cells = <1>;
> +	reg = <0x0 0xa01b0000 0x0 0x1000>;
> +
> +	ipmi0: bt@e4 {
> +		compatible = "ipmi-bt";
> +		device_type = "ipmi";
> +		reg = <0x01 0xe4 0x04>;
> +		status = "disabled";
> +	};
> +};


This documentation file needs to be part of the next patch. It has nothing to do with
what you are trying to fix here.


> diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
> index 136735d..c26b7cc 100644
> --- a/arch/arm64/include/asm/io.h
> +++ b/arch/arm64/include/asm/io.h
> @@ -175,6 +175,12 @@ static inline u64 __raw_readq(const volatile void __iomem *addr)
>  #define outsl outsl
>  
>  DECLARE_EXTIO(l, u32)
> +
> +#define indirect_io_enabled indirect_io_enabled
> +extern bool indirect_io_enabled(void);
> +
> +#define addr_is_indirect_io addr_is_indirect_io
> +extern int addr_is_indirect_io(u64 taddr);
>  #endif
>  
>  
> diff --git a/arch/arm64/kernel/extio.c b/arch/arm64/kernel/extio.c
> index 647b3fa..3d45fa8 100644
> --- a/arch/arm64/kernel/extio.c
> +++ b/arch/arm64/kernel/extio.c
> @@ -19,6 +19,31 @@
>  
>  struct extio_ops *arm64_extio_ops;
>  
> +/**
> + * indirect_io_enabled - check whether indirectIO is enabled.
> + *	arm64_extio_ops will be set only when indirectIO mechanism had been
> + *	initialized.
> + *
> + * Returns true when indirectIO is enabled.
> + */
> +bool indirect_io_enabled(void)
> +{
> +	return arm64_extio_ops ? true : false;
> +}
> +
> +/**
> + * addr_is_indirect_io - check whether the input taddr is for indirectIO.
> + * @taddr: the io address to be checked.
> + *
> + * Returns 1 when taddr is in the range; otherwise return 0.
> + */
> +int addr_is_indirect_io(u64 taddr)
> +{
> +	if (arm64_extio_ops->start > taddr || arm64_extio_ops->end < taddr)

start >= taddr ?

> +		return 0;
> +
> +	return 1;
> +}
>  
>  BUILD_EXTIO(b, u8)
>  
> diff --git a/drivers/of/address.c b/drivers/of/address.c
> index 02b2903..cc2a05d 100644
> --- a/drivers/of/address.c
> +++ b/drivers/of/address.c
> @@ -479,6 +479,50 @@ static int of_empty_ranges_quirk(struct device_node *np)
>  	return false;
>  }
>  
> +
> +/*
> + * of_isa_indirect_io - get the IO address from some isa reg property value.
> + *	For some isa/lpc devices, no ranges property in ancestor node.
> + *	The device addresses are described directly in their regs property.
> + *	This fixup function will be called to get the IO address of isa/lpc
> + *	devices when the normal of_translation failed.
> + *
> + * @parent:	points to the parent dts node;
> + * @bus:		points to the of_bus which can be used to parse address;
> + * @addr:	the address from reg property;
> + * @na:		the address cell counter of @addr;
> + * @presult:	store the address paresed from @addr;
> + *
> + * return 1 when successfully get the I/O address;
> + * 0 will return for some failures.

Bah, you are returning a signed int, why 0 for failure? Return a negative value with
error codes. Otherwise change the return value into a bool.

> + */
> +static int of_get_isa_indirect_io(struct device_node *parent,
> +				struct of_bus *bus, __be32 *addr,
> +				int na, u64 *presult)
> +{
> +	unsigned int flags;
> +	unsigned int rlen;
> +
> +	/* whether support indirectIO */
> +	if (!indirect_io_enabled())
> +		return 0;
> +
> +	if (!of_bus_isa_match(parent))
> +		return 0;
> +
> +	flags = bus->get_flags(addr);
> +	if (!(flags & IORESOURCE_IO))
> +		return 0;
> +
> +	/* there is ranges property, apply the normal translation directly. */

s/there is ranges/if we have a 'ranges'/

> +	if (of_get_property(parent, "ranges", &rlen))
> +		return 0;
> +
> +	*presult = of_read_number(addr + 1, na - 1);
> +	/* this fixup is only valid for specific I/O range. */
> +	return addr_is_indirect_io(*presult);
> +}
> +
>  static int of_translate_one(struct device_node *parent, struct of_bus *bus,
>  			    struct of_bus *pbus, __be32 *addr,
>  			    int na, int ns, int pna, const char *rprop)
> @@ -595,6 +639,15 @@ static u64 __of_translate_address(struct device_node *dev,
>  			result = of_read_number(addr, na);
>  			break;
>  		}
> +		/*
> +		 * For indirectIO device which has no ranges property, get
> +		 * the address from reg directly.
> +		 */
> +		if (of_get_isa_indirect_io(dev, bus, addr, na, &result)) {
> +			pr_debug("isa indirectIO matched(%s)..addr = 0x%llx\n",
> +				of_node_full_name(dev), result);
> +			break;
> +		}
>  
>  		/* Get new parent bus and counts */
>  		pbus = of_match_bus(parent);
> @@ -688,8 +741,9 @@ static int __of_address_to_resource(struct device_node *dev,
>  	if (taddr == OF_BAD_ADDR)
>  		return -EINVAL;
>  	memset(r, 0, sizeof(struct resource));
> -	if (flags & IORESOURCE_IO) {
> +	if (flags & IORESOURCE_IO && taddr >= PCIBIOS_MIN_IO) {
>  		unsigned long port;
> +
>  		port = pci_address_to_pio(taddr);
>  		if (port == (unsigned long)-1)
>  			return -EINVAL;
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index ba34907..1a08511 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -3263,7 +3263,7 @@ int __weak pci_register_io_range(phys_addr_t addr, resource_size_t size)
>  
>  #ifdef PCI_IOBASE
>  	struct io_range *range;
> -	resource_size_t allocated_size = 0;
> +	resource_size_t allocated_size = PCIBIOS_MIN_IO;
>  
>  	/* check if the range hasn't been previously recorded */
>  	spin_lock(&io_range_lock);
> @@ -3312,7 +3312,7 @@ phys_addr_t pci_pio_to_address(unsigned long pio)
>  
>  #ifdef PCI_IOBASE
>  	struct io_range *range;
> -	resource_size_t allocated_size = 0;
> +	resource_size_t allocated_size = PCIBIOS_MIN_IO;

Have you checked that pci_pio_to_address still returns valid values after this? I know that
you are trying to take into account PCIBIOS_MIN_IO limit when allocating reserving the IO ranges,
but the values added in the io_range_list are still starting from zero, no from PCIBIOS_MIN_IO,
so the calculation of the address in this function could return negative values casted to pci_addr_t.

Maybe you want to adjust the range->start value in pci_register_io_range() as well to have it
offset by PCIBIOS_MIN_IO as well.

Best regards,
Liviu

>  
>  	if (pio > IO_SPACE_LIMIT)
>  		return address;
> @@ -3335,7 +3335,7 @@ unsigned long __weak pci_address_to_pio(phys_addr_t address)
>  {
>  #ifdef PCI_IOBASE
>  	struct io_range *res;
> -	resource_size_t offset = 0;
> +	resource_size_t offset = PCIBIOS_MIN_IO;
>  	unsigned long addr = -1;
>  
>  	spin_lock(&io_range_lock);
> diff --git a/include/linux/of_address.h b/include/linux/of_address.h
> index 3786473..deec469 100644
> --- a/include/linux/of_address.h
> +++ b/include/linux/of_address.h
> @@ -24,6 +24,23 @@ struct of_pci_range {
>  #define for_each_of_pci_range(parser, range) \
>  	for (; of_pci_range_parser_one(parser, range);)
>  
> +
> +#ifndef indirect_io_enabled
> +#define indirect_io_enabled indirect_io_enabled
> +static inline bool indirect_io_enabled(void)
> +{
> +	return false;
> +}
> +#endif
> +
> +#ifndef addr_is_indirect_io
> +#define addr_is_indirect_io addr_is_indirect_io
> +static inline int addr_is_indirect_io(u64 taddr)
> +{
> +	return 0;
> +}
> +#endif
> +
>  /* Translate a DMA address from device space to CPU space */
>  extern u64 of_translate_dma_address(struct device_node *dev,
>  				    const __be32 *in_addr);
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 0e49f70..7f6bbb6 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -2130,4 +2130,12 @@ static inline bool pci_ari_enabled(struct pci_bus *bus)
>  /* provide the legacy pci_dma_* API */
>  #include <linux/pci-dma-compat.h>
>  
> +/*
> + * define this macro here to refrain from compilation error for some
> + * platforms. Please keep this macro at the end of this header file.
> + */
> +#ifndef PCIBIOS_MIN_IO
> +#define PCIBIOS_MIN_IO		0
> +#endif
> +
>  #endif /* LINUX_PCI_H */
> -- 
> 1.9.1
> 
> --
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-- 
====================
| I would like to |
| fix the world,  |
| but they're not |
| giving me the   |
 \ source code!  /
  ---------------
    ¯\_(ツ)_/¯

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