Re: [PATCH V4 2/2] PCI/ACPI: hisi: Add ACPI support for HiSilicon SoCs Host Controllers

[Bjorn Helgaas]

On Wed, Nov 16, 2016 at 07:59:38PM +0800, Dongdong Liu wrote:
> Hi Bjorn
> 
> Many Thanks for your review
> 
> å 2016/11/15 7:33, Bjorn Helgaas åé:
> >On Wed, Nov 09, 2016 at 05:14:57PM +0800, Dongdong Liu wrote:
> >>PCIe controller in Hip05/HIP06/HIP07 SoCs is not ECAM compliant.
> >>It is non ECAM only for the RC bus config space;for any other bus
> >>underneath the root bus we support ECAM access.
> >>Add specific quirks for PCI config space accessors.This involves:
> >>1. New initialization call hisi_pcie_init() to obtain rc base
> >>addresses from PNP0C02 as subdevice of PNP0A03.
> >>2. New entry in common quirk array.
> >>
> >>Signed-off-by: Dongdong Liu <liudongdong3@xxxxxxxxxx>
> >>Signed-off-by: Gabriele Paoloni <gabriele.paoloni@xxxxxxxxxx>
> >>---
> >> MAINTAINERS                       |   1 +
> >> drivers/acpi/pci_mcfg.c           |  13 ++++
> >> drivers/pci/host/Kconfig          |   8 ++
> >> drivers/pci/host/Makefile         |   1 +
> >> drivers/pci/host/pcie-hisi-acpi.c | 157 ++++++++++++++++++++++++++++++++++++++
> >> include/linux/pci-ecam.h          |   5 ++
> >> 6 files changed, 185 insertions(+)
> >> create mode 100644 drivers/pci/host/pcie-hisi-acpi.c
> >>
> >>diff --git a/MAINTAINERS b/MAINTAINERS
> >>index 1cd38a7..b224caa 100644
> >>--- a/MAINTAINERS
> >>+++ b/MAINTAINERS
> >>@@ -9358,6 +9358,7 @@ L:	linux-pci@xxxxxxxxxxxxxxx
> >> S:	Maintained
> >> F:	Documentation/devicetree/bindings/pci/hisilicon-pcie.txt
> >> F:	drivers/pci/host/pcie-hisi.c
> >>+F:	drivers/pci/host/pcie-hisi-acpi.c
> >>
> >> PCIE DRIVER FOR ROCKCHIP
> >> M:	Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
> >>diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
> >>index ac21db3..b1b6fc7 100644
> >>--- a/drivers/acpi/pci_mcfg.c
> >>+++ b/drivers/acpi/pci_mcfg.c
> >>@@ -57,6 +57,19 @@ struct mcfg_fixup {
> >> 	{ "QCOM  ", "QDF2432 ", 1, 5, MCFG_BUS_ANY, &pci_32b_ops },
> >> 	{ "QCOM  ", "QDF2432 ", 1, 6, MCFG_BUS_ANY, &pci_32b_ops },
> >> 	{ "QCOM  ", "QDF2432 ", 1, 7, MCFG_BUS_ANY, &pci_32b_ops },
> >>+#ifdef CONFIG_PCI_HISI_ACPI
> >>+	#define PCI_ACPI_QUIRK_QUAD_DOM(table_id, seg, ops) \
> >>+	{ "HISI  ", table_id, 0, seg + 0, MCFG_BUS_ANY, ops }, \
> >>+	{ "HISI  ", table_id, 0, seg + 1, MCFG_BUS_ANY, ops }, \
> >>+	{ "HISI  ", table_id, 0, seg + 2, MCFG_BUS_ANY, ops }, \
> >>+	{ "HISI  ", table_id, 0, seg + 3, MCFG_BUS_ANY, ops }
> >>+	PCI_ACPI_QUIRK_QUAD_DOM("HIP05   ", 0, &hisi_pcie_ops),
> >>+	PCI_ACPI_QUIRK_QUAD_DOM("HIP06   ", 0, &hisi_pcie_ops),
> >>+	PCI_ACPI_QUIRK_QUAD_DOM("HIP07   ", 0, &hisi_pcie_ops),
> >>+	PCI_ACPI_QUIRK_QUAD_DOM("HIP07   ", 4, &hisi_pcie_ops),
> >>+	PCI_ACPI_QUIRK_QUAD_DOM("HIP07   ", 8, &hisi_pcie_ops),
> >>+	PCI_ACPI_QUIRK_QUAD_DOM("HIP07   ", 12, &hisi_pcie_ops),
> >>+#endif
> >> };
> >>
> >> static char mcfg_oem_id[ACPI_OEM_ID_SIZE];
> >>diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
> >>index ae98644..9ff2bcd 100644
> >>--- a/drivers/pci/host/Kconfig
> >>+++ b/drivers/pci/host/Kconfig
> >>@@ -227,6 +227,14 @@ config PCI_HISI
> >> 	  Say Y here if you want PCIe controller support on HiSilicon
> >> 	  Hip05 and Hip06 and Hip07 SoCs
> >>
> >>+config PCI_HISI_ACPI
> >>+	depends on ACPI && ARM64
> >>+	bool "HiSilicon Hip05 and Hip06 and Hip07 SoCs ACPI PCIe controllers"
> >>+	select PNP
> >>+	help
> >>+	  Say Y here if you want ACPI PCIe controller support on HiSilicon
> >>+	  Hip05 and Hip06 and Hip07 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 084cb49..9402858 100644
> >>--- a/drivers/pci/host/Makefile
> >>+++ b/drivers/pci/host/Makefile
> >>@@ -26,6 +26,7 @@ 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
> >>+obj-$(CONFIG_PCI_HISI_ACPI) += pcie-hisi-acpi.o
> >> obj-$(CONFIG_PCIE_QCOM) += pcie-qcom.o
> >> obj-$(CONFIG_PCI_HOST_THUNDER_ECAM) += pci-thunder-ecam.o
> >> obj-$(CONFIG_PCI_HOST_THUNDER_PEM) += pci-thunder-pem.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..aade4b5
> >>--- /dev/null
> >>+++ b/drivers/pci/host/pcie-hisi-acpi.c
> >>@@ -0,0 +1,157 @@
> >>+/*
> >>+ * 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/pci.h>
> >>+#include <linux/pci-acpi.h>
> >>+#include <linux/pci-ecam.h>
> >>+
> >>+#define DEBUG0				0x728
> >>+#define PCIE_LTSSM_LINKUP_STATE		0x11
> >>+#define PCIE_LTSSM_STATE_MASK		0x3F
> >
> >These are now unused.
> 
> Thanks for pointing that, will delete them.
> 
> >
> >>+static const struct acpi_device_id hisi_pcie_rc_res_ids[] = {
> >>+	{"HISI0081", 0},
> >>+	{"", 0},
> >>+};
> >>+
> >>+static int hisi_pcie_acpi_rd_conf(struct pci_bus *bus, u32 devfn, int where,
> >>+				  int size, u32 *val)
> >>+{
> >>+	struct pci_config_window *cfg = bus->sysdata;
> >>+	int dev = PCI_SLOT(devfn);
> >>+
> >>+	if (bus->number == cfg->busr.start) {
> >>+		/* access only one slot on each root port */
> >>+		if (dev > 0)
> >>+			return PCIBIOS_DEVICE_NOT_FOUND;
> >>+		else
> >>+			return pci_generic_config_read32(bus, devfn, where,
> >>+							 size, val);
> >>+	}
> >>+
> >>+	return pci_generic_config_read(bus, devfn, where, size, val);
> >>+}
> >>+
> >>+static int hisi_pcie_acpi_wr_conf(struct pci_bus *bus, u32 devfn,
> >>+				  int where, int size, u32 val)
> >>+{
> >>+	struct pci_config_window *cfg = bus->sysdata;
> >>+	int dev = PCI_SLOT(devfn);
> >>+
> >>+	if (bus->number == cfg->busr.start) {
> >>+		/* access only one slot on each root port */
> >>+		if (dev > 0)
> >>+			return PCIBIOS_DEVICE_NOT_FOUND;
> >>+		else
> >>+			return pci_generic_config_write32(bus, devfn, where,
> >>+							  size, val);
> >>+	}
> >>+
> >>+	return pci_generic_config_write(bus, devfn, where, size, val);
> >>+}
> >>+
> >>+static void __iomem *hisi_pcie_map_bus(struct pci_bus *bus, unsigned int devfn,
> >>+				       int where)
> >>+{
> >>+	struct pci_config_window *cfg = bus->sysdata;
> >>+	void __iomem *reg_base = cfg->priv;
> >>+
> >>+	if (bus->number == cfg->busr.start)
> >>+		return reg_base + where;
> >>+	else
> >>+		return pci_ecam_map_bus(bus, devfn, where);
> >>+}
> >>+
> >>+/*
> >>+ * Retrieve RC base and size from sub-device under the RC
> >>+ * Device (RES1)
> >>+ * {
> >>+ *	Name (_HID, "HISI0081")
> >>+ *	Name (_CID, "PNP0C02")
> >>+ *	Name (_CRS, ResourceTemplate (){
> >>+ *		Memory32Fixed (ReadWrite, 0xb0080000, 0x10000)
> >>+ *	})
> >>+ * }
> >>+ */
> >>+static int hisi_pcie_rc_addr_get(struct acpi_device *adev,
> >>+				 void __iomem **addr)
> >>+{
> >>+	struct acpi_device *child_adev;
> >>+	struct list_head list;
> >>+	struct resource *res;
> >>+	struct resource_entry *entry;
> >>+	unsigned long flags;
> >>+	int ret;
> >>+
> >>+	list_for_each_entry(child_adev, &adev->children, node) {
> >>+		ret = acpi_match_device_ids(child_adev, hisi_pcie_rc_res_ids);
> >>+		if (ret)
> >>+			continue;
> >>+
> >>+		INIT_LIST_HEAD(&list);
> >>+		flags = IORESOURCE_MEM;
> >>+		ret = acpi_dev_get_resources(child_adev, &list,
> >>+					     acpi_dev_filter_resource_type_cb,
> >>+					     (void *)flags);
> >>+		if (ret < 0) {
> >>+			dev_err(&child_adev->dev,
> >>+				"failed to parse _CRS method, error code %d\n",
> >>+				ret);
> >>+			return ret;
> >>+		} else if (ret == 0) {
> >>+			dev_err(&child_adev->dev,
> >>+				"no IO and memory resources present in _CRS\n");
> >>+			return -EINVAL;
> >>+		}
> >>+
> >>+		entry = list_first_entry(&list, struct resource_entry, node);
> >>+		res = entry->res;
> >>+		*addr = devm_ioremap(&child_adev->dev,
> >>+				     res->start, resource_size(res));
> >>+		acpi_dev_free_resource_list(&list);
> >>+		if (IS_ERR(*addr)) {
> >>+			dev_err(&child_adev->dev, "error with ioremap\n");
> >>+			return -ENOMEM;
> >>+		}
> >>+
> >>+		return 0;
> >>+	}
> >>+
> >>+	return -EINVAL;
> >>+}
> >
> >OK, so MCFG (with the possible help of quirks) tells us where *most*
> >of this RC's ECAM space is, but it doesn't tell us where the root bus
> >ECAM space is, which is why we need this block of ugly code.  Right?
> Yes, correct.
> >
> >Is there any way we can compute the root bus reg_base from the address
> >we got from MCFG?
> 
> No, we can not,because RC base addresses are sequntial and MCFG impose a 4k boundaries.

I understand the "no" part, but not the "because ..." part :)

I think the regions described by MCFG are aligned on 1MB boundaries,
not 4K, because MCFG tells you about ECAM space for a given bus number
range.  Each bus can have 256 devices (5 bit device number + 3 bit
function number), and each device has 4K of config space.  256 * 4KB =
1MB.

In any case, it wouldn't have to be a simple function like this:

  reg_base = pci_mcfg_lookup(seg, [bus 01]) - 1MB

It could be *anything*, e.g.,

  reg_base = 0x00100000 + (bus_num * 4096);

> >Is it a constant that realistically is not going to be modified?
> 
> Yes, this is a hardware limitation

If there's only one RC and the address is a constant, maybe you can
just hard-code the address in the .map_bus() function?

Bjorn