RE: [RFC PATCH v3 3/3] PCI/ACPI: hisi: Add ACPI support for HiSilicon SoCs Host Controllers

[Gabriele Paoloni]

Hi Mark

> -----Original Message-----
> From: Mark Rutland [mailto:mark.rutland@xxxxxxx]
> Sent: 09 February 2016 18:24
> To: Gabriele Paoloni
> Cc: Guohanjun (Hanjun Guo); Wangzhou (B); liudongdong (C); Linuxarm;
> qiujiang; bhelgaas@xxxxxxxxxx; arnd@xxxxxxxx;
> Lorenzo.Pieralisi@xxxxxxx; tn@xxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; xuwei (O); linux-acpi@xxxxxxxxxxxxxxx;
> jcm@xxxxxxxxxx; zhangjukuo; Liguozhu (Kenneth); linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [RFC PATCH v3 3/3] PCI/ACPI: hisi: Add ACPI support for
> HiSilicon SoCs Host Controllers
> 
> On Tue, Feb 09, 2016 at 05:34:20PM +0000, Gabriele Paoloni wrote:
> > From: gabriele paoloni <gabriele.paoloni@xxxxxxxxxx>
> >
> > This patch adds specific quirks for PCI config space accessors,
> > it uses _HID to decide whether to hook pci_ops or not.
> 
> If I understand correctly, this would mean that it's not actually ECAM
> compliant, then?

Correct we need out own methods to read/write the RC config space...see
for example:

+	if (bus->number == root->secondary.start)
+		return hisi_pcie_common_cfg_read(reg_base, where, size, val);
+
+	return pci_generic_config_read(bus, devfn, where, size, val);

> 
> > Signed-off-by: Dongdong Liu <liudongdong3@xxxxxxxxxx>
> > Signed-off-by: Gabriele Paoloni <gabriele.paoloni@xxxxxxxxxx>
> > ---
> >  MAINTAINERS                       |   1 +
> >  drivers/pci/host/Kconfig          |   8 ++
> >  drivers/pci/host/Makefile         |   1 +
> >  drivers/pci/host/pcie-hisi-acpi.c | 188
> ++++++++++++++++++++++++++++++++++++++
> >  drivers/pci/host/pcie-hisi.c      |   2 -
> >  drivers/pci/host/pcie-hisi.h      |   2 +
> >  6 files changed, 200 insertions(+), 2 deletions(-)
> >  create mode 100644 drivers/pci/host/pcie-hisi-acpi.c
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index d69f436..f184c3e 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -8412,6 +8412,7 @@ F:
> 	Documentation/devicetree/bindings/pci/hisilicon-pcie.txt
> >  F:	drivers/pci/host/pcie-hisi.h
> >  F:	drivers/pci/host/pcie-hisi.c
> >  F:	drivers/pci/host/pcie-hisi-common.c
> > +F:	drivers/pci/host/pcie-hisi-acpi.c
> >
> >  PCIE DRIVER FOR QUALCOMM MSM
> >  M:     Stanimir Varbanov <svarbanov@xxxxxxxxxx>
> > diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
> > index 75a6054..65b1add 100644
> > --- a/drivers/pci/host/Kconfig
> > +++ b/drivers/pci/host/Kconfig
> > @@ -181,6 +181,14 @@ config PCI_HISI
> >  	  Say Y here if you want PCIe controller support on HiSilicon
> >  	  Hip05 and Hip06 SoCs
> >
> > +config PCI_HISI_ACPI
> > +	depends on ACPI
> > +	bool "HiSilicon Hip05 and Hip06 SoCs ACPI PCIe controllers"
> > +	select ACPI_PCI_HOST_GENERIC
> > +	help
> > +	  Say Y here if you want ACPI PCIe controller support on
> HiSilicon
> > +	  Hip05 and Hip06 SoCs
> > +
> >  config PCIE_QCOM
> >  	bool "Qualcomm PCIe controller"
> >  	depends on ARCH_QCOM && OF
> > diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
> > index 8c93c0f..57e4379 100644
> > --- a/drivers/pci/host/Makefile
> > +++ b/drivers/pci/host/Makefile
> > @@ -21,4 +21,5 @@ obj-$(CONFIG_PCIE_IPROC_BCMA) += pcie-iproc-bcma.o
> >  obj-$(CONFIG_PCIE_ALTERA) += pcie-altera.o
> >  obj-$(CONFIG_PCIE_ALTERA_MSI) += pcie-altera-msi.o
> >  obj-$(CONFIG_PCI_HISI) += pcie-hisi.o pcie-hisi-common.o
> > +obj-$(CONFIG_PCI_HISI_ACPI) += pcie-hisi-acpi.o pcie-hisi-common.o
> >  obj-$(CONFIG_PCIE_QCOM) += pcie-qcom.o
> > diff --git a/drivers/pci/host/pcie-hisi-acpi.c
> b/drivers/pci/host/pcie-hisi-acpi.c
> > new file mode 100644
> > index 0000000..3605260
> > --- /dev/null
> > +++ b/drivers/pci/host/pcie-hisi-acpi.c
> > @@ -0,0 +1,188 @@
> > +/*
> > + * PCIe host controller driver for HiSilicon HipXX SoCs
> > + *
> > + * Copyright (C) 2016 HiSilicon Co., Ltd. http://www.hisilicon.com
> > + *
> > + * Author: Dongdong Liu <liudongdong3@xxxxxxxxxx>
> > + *         Gabriele Paoloni <gabriele.paoloni@xxxxxxxxxx>
> > + *
> > + * This program is free software; you can redistribute it and/or
> modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +#include <linux/interrupt.h>
> > +#include <linux/acpi.h>
> > +#include <linux/ecam.h>
> > +#include <linux/pci.h>
> > +#include <linux/pci-acpi.h>
> > +#include "pcie-hisi.h"
> > +
> > +#define GET_PCIE_LINK_STATUS  0x0
> > +
> > +/* uuid 6d30f553-836c-408e-b6ad-45bccc957949 */
> > +const u8 hisi_pcie_acpi_dsm_uuid[] = {
> > +	0x53, 0xf5, 0x30, 0x6d, 0x6c, 0x83, 0x8e, 0x40,
> > +	0xb6, 0xad, 0x45, 0xbc, 0xcc, 0x95, 0x79, 0x49
> > +};
> > +
> > +static const struct acpi_device_id hisi_pcie_ids[] = {
> > +	{"HISI0080", 0},
> > +	{"", 0},
> > +};
> > +
> > +static int hisi_pcie_get_addr(struct acpi_pci_root *root, const char
> *name,
> > +				void __iomem **addr)
> > +{
> > +	struct acpi_device *device;
> > +	u64 base;
> > +	u64 size;
> > +	u32 buf[4];
> > +	int ret;
> > +
> > +	device =  root->device;
> > +	ret = fwnode_property_read_u32_array(&device->fwnode, name,
> > +					buf, ARRAY_SIZE(buf));
> > +	if (ret) {
> > +		dev_err(&device->dev, "can't get %s\n", name);
> > +		return ret;
> > +	}
> > +
> > +	base = ((u64)buf[0] << 32) | buf[1];
> > +	size =  ((u64)buf[2] << 32) | buf[3];
> > +	*addr = devm_ioremap(&device->dev, base, size);
> > +	if (!(*addr)) {
> > +		dev_err(&device->dev, "error with ioremap\n");
> > +		return -ENOMEM;
> > +	}
> 
> This does not seem like the correct way of describing an addres in
> ACPI.

Ok I guess this is related to the comment below...

> 
> > +
> > +	return 0;
> > +}
> > +
> > +
> > +static int hisi_pcie_link_up_acpi(struct acpi_pci_root *root)
> > +{
> > +	u32 val;
> > +	struct acpi_device *device;
> > +	union acpi_object *obj;
> > +
> > +	device = root->device;
> > +	obj = acpi_evaluate_dsm(device->handle,
> > +		hisi_pcie_acpi_dsm_uuid, 0,
> > +		GET_PCIE_LINK_STATUS, NULL);
> > +
> > +	if (!obj  ||  obj->type != ACPI_TYPE_INTEGER)  {
> > +		dev_err(&device->dev, "can't get link status from _DSM\n");
> > +		return 0;
> > +	}
> > +	val = obj->integer.value;
> > +
> > +	return ((val & PCIE_LTSSM_STATE_MASK) ==
> PCIE_LTSSM_LINKUP_STATE);
> > +
> > +}
> > +
> > +/*
> > + * Retrieve rc_dbi base and size from _DSD
> > + * Name (_DSD, Package () {
> > + *	ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
> > + *	Package () {
> > + *	Package () {"rc-dbi", Package () { 0x0, 0xb0080000, 0x0, 0x10000
> }},
> > + *	}
> > + *	})
> > + */
> 
> As above, this does not look right. ACPI has standard mechanisms for
> describing addresses. Making something up like this is not a good idea.
 
I am quite new to ACPI, may I ask you to explain a bit? 
In our case we need to put somewhere in the ACPI table the value of 
the base register address used to read/write the RC config space... 

Do you have any suggestion about the correct place to put it?

Many Thanks

Gab

> 
> Mark.