Linux-PCI Archive on lore.kernel.org
 help / color / Atom feed
* [PATCH 1/3] pci: designware: add driver for DWC controller in ECAM shift mode
  2017-08-21 19:29 [PATCH 0/3] pci: add support for firmware initialized designware RCs Ard Biesheuvel
@ 2017-08-21 19:29 ` Ard Biesheuvel
  2017-08-24 16:24   ` kbuild test robot
  2017-08-24 16:25   ` kbuild test robot
  0 siblings, 2 replies; 3+ messages in thread
From: Ard Biesheuvel @ 2017-08-21 19:29 UTC (permalink / raw)
  To: linux-pci
  Cc: Joao Pinto, Graeme Gregory, Ard Biesheuvel, Marc Zyngier,
	Jingoo Han, Leif Lindholm, Bjorn Helgaas, linux-arm-kernel

Some implementations of the Synopsys Designware PCIe controller implement
a so-called ECAM shift mode, which allows a static memory window to be
configured that covers the configuration space of the entire bus range.

If the firmware performs all the low level configuration that is required
to expose this controller in a fully ECAM compatible manner, we can
simply describe it as "pci-host-ecam-generic" and be done with it.
However, it appears that in some cases (one of which is the Armada 80x0),
the IP is synthesized with an ATU window size that does not allow the
first bus to be mapped in a way that prevents the device on the
downstream port from appearing more than once.

So implement a driver that relies on the firmware to perform all low
level initialization, and drives the controller in ECAM mode, but
overrides the config space accessors to take the above quirk into
account.

Note that, unlike most drivers for this IP, this driver does not expose
a fake bridge device at B/D/F 00:00.0. There is no point in doing so,
given that this is not a true bridge, and does not require any windows
to be configured in order for the downstream device to operate correctly.
Omitting it also prevents the PCI resource allocation routines from
handing out BAR space to it unnecessarily.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Joao Pinto <Joao.Pinto@synopsys.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 drivers/pci/dwc/Kconfig                | 11 +++
 drivers/pci/dwc/Makefile               |  1 +
 drivers/pci/dwc/pcie-designware-ecam.c | 75 ++++++++++++++++++++
 3 files changed, 87 insertions(+)

diff --git a/drivers/pci/dwc/Kconfig b/drivers/pci/dwc/Kconfig
index d275aadc47ee..f2afa2c519c1 100644
--- a/drivers/pci/dwc/Kconfig
+++ b/drivers/pci/dwc/Kconfig
@@ -169,4 +169,15 @@ config PCIE_KIRIN
 	  Say Y here if you want PCIe controller support
 	  on HiSilicon Kirin series SoCs.
 
+config PCIE_DW_HOST_ECAM
+	bool "Synopsys DesignWare PCIe controller in ECAM mode"
+	depends on OF
+	select PCI_HOST_COMMON
+	select IRQ_DOMAIN
+	help
+	  Add support for Synopsys DesignWare PCIe controllers configured
+	  by the firmware into ECAM shift mode. In some cases, these are
+	  fully ECAM compliant, in which case the pci-host-generic driver
+	  may be used instead.
+
 endmenu
diff --git a/drivers/pci/dwc/Makefile b/drivers/pci/dwc/Makefile
index c61be9738cce..7d5a23e5b767 100644
--- a/drivers/pci/dwc/Makefile
+++ b/drivers/pci/dwc/Makefile
@@ -1,5 +1,6 @@
 obj-$(CONFIG_PCIE_DW) += pcie-designware.o
 obj-$(CONFIG_PCIE_DW_HOST) += pcie-designware-host.o
+obj-$(CONFIG_PCIE_DW_HOST_ECAM) += pcie-designware-ecam.o
 obj-$(CONFIG_PCIE_DW_EP) += pcie-designware-ep.o
 obj-$(CONFIG_PCIE_DW_PLAT) += pcie-designware-plat.o
 ifneq ($(filter y,$(CONFIG_PCI_DRA7XX_HOST) $(CONFIG_PCI_DRA7XX_EP)),)
diff --git a/drivers/pci/dwc/pcie-designware-ecam.c b/drivers/pci/dwc/pcie-designware-ecam.c
new file mode 100644
index 000000000000..0f495bd2e33e
--- /dev/null
+++ b/drivers/pci/dwc/pcie-designware-ecam.c
@@ -0,0 +1,75 @@
+/*
+ * Driver for mostly ECAM compatible Synopsys dw PCIe controllers
+ * configured by the firmware into RC mode
+ *
+ * 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.
+ *
+ * Copyright (C) 2014 ARM Limited
+ * Copyright (C) 2017 Linaro Limited
+ *
+ * Authors: Will Deacon <will.deacon@arm.com>
+ *          Ard Biesheuvel <ard.biesheuvel@linaro.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/of_address.h>
+#include <linux/of_pci.h>
+#include <linux/pci-ecam.h>
+#include <linux/platform_device.h>
+
+static int pci_dw_ecam_config_read(struct pci_bus *bus, u32 devfn, int where,
+				   int size, u32 *val)
+{
+	struct pci_config_window *cfg = bus->sysdata;
+
+	/*
+	 * The Synopsys dw PCIe controller in RC mode will not filter type 0
+	 * config TLPs sent to devices 1 and up on its downstream port,
+	 * resulting in devices appearing multiple times on bus 0 unless we
+	 * filter them here.
+	 */
+	if (bus->number == cfg->busr.start && PCI_SLOT(devfn) > 0) {
+		*val = 0xffffffff;
+		return PCIBIOS_DEVICE_NOT_FOUND;
+	}
+	return pci_generic_config_read(bus, devfn, where, size, val);
+}
+
+static int pci_dw_ecam_config_write(struct pci_bus *bus, u32 devfn, int where,
+				    int size, u32 val)
+{
+	struct pci_config_window *cfg = bus->sysdata;
+
+	if (bus->number == cfg->busr.start && PCI_SLOT(devfn) > 0)
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
+	return pci_generic_config_write(bus, devfn, where, size, val);
+}
+
+static struct pci_ecam_ops pci_dw_ecam_bus_ops = {
+	.pci_ops.map_bus		= pci_ecam_map_bus,
+	.pci_ops.read			= pci_dw_ecam_config_read,
+	.pci_ops.write			= pci_dw_ecam_config_write,
+	.bus_shift			= 20,
+};
+
+static const struct of_device_id pci_dw_ecam_of_match[] = {
+	{ .compatible = "snps,dw-pcie-ecam" },
+	{ },
+};
+
+static int pci_dw_ecam_probe(struct platform_device *pdev)
+{
+	return pci_host_common_probe(pdev, &pci_dw_ecam_bus_ops);
+}
+
+static struct platform_driver pci_dw_ecam_driver = {
+	.driver.name			= "pcie-designware-ecam",
+	.driver.of_match_table		= pci_dw_ecam_of_match,
+	.driver.suppress_bind_attrs	= true,
+	.probe				= pci_dw_ecam_probe,
+};
+builtin_platform_driver(pci_dw_ecam_driver);
-- 
2.11.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH 1/3] pci: designware: add driver for DWC controller in ECAM shift mode
  2017-08-21 19:29 ` [PATCH 1/3] pci: designware: add driver for DWC controller in ECAM shift mode Ard Biesheuvel
  2017-08-24 16:24   ` kbuild test robot
@ 2017-08-24 16:25   ` kbuild test robot
  1 sibling, 0 replies; 3+ messages in thread
From: kbuild test robot @ 2017-08-24 16:25 UTC (permalink / raw)
  To: Ard Biesheuvel
  Cc: Joao Pinto, Graeme Gregory, Ard Biesheuvel, Marc Zyngier,
	linux-pci, Leif Lindholm, kbuild-all, Jingoo Han, Bjorn Helgaas,
	linux-arm-kernel


[-- Attachment #1: Type: text/plain, Size: 1057 bytes --]

Hi Ard,

[auto build test WARNING on pci/next]
[also build test WARNING on v4.13-rc6 next-20170824]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Ard-Biesheuvel/pci-add-support-for-firmware-initialized-designware-RCs/20170824-232638
base:   https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git next
config: mips-allmodconfig (attached as .config)
compiler: mips-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=mips 

All warnings (new ones prefixed by >>):

warning: (PCIE_DW_HOST_ECAM) selects PCI_HOST_COMMON which has unmet direct dependencies (PCI)

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 47113 bytes --]

[-- Attachment #3: Type: text/plain, Size: 176 bytes --]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH 1/3] pci: designware: add driver for DWC controller in ECAM shift mode
  2017-08-21 19:29 ` [PATCH 1/3] pci: designware: add driver for DWC controller in ECAM shift mode Ard Biesheuvel
@ 2017-08-24 16:24   ` kbuild test robot
  2017-08-24 16:25   ` kbuild test robot
  1 sibling, 0 replies; 3+ messages in thread
From: kbuild test robot @ 2017-08-24 16:24 UTC (permalink / raw)
  To: Ard Biesheuvel
  Cc: Joao Pinto, Graeme Gregory, Ard Biesheuvel, Marc Zyngier,
	linux-pci, Leif Lindholm, kbuild-all, Jingoo Han, Bjorn Helgaas,
	linux-arm-kernel


[-- Attachment #1: Type: text/plain, Size: 1040 bytes --]

Hi Ard,

[auto build test WARNING on pci/next]
[also build test WARNING on v4.13-rc6 next-20170824]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Ard-Biesheuvel/pci-add-support-for-firmware-initialized-designware-RCs/20170824-232638
base:   https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git next
config: m68k-allmodconfig (attached as .config)
compiler: m68k-linux-gcc (GCC) 4.9.0
reproduce:
        wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=m68k 

All warnings (new ones prefixed by >>):

warning: (PCIE_DW_HOST_ECAM) selects PCI_HOST_COMMON which has unmet direct dependencies (MMU && PCI)

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 43721 bytes --]

[-- Attachment #3: Type: text/plain, Size: 176 bytes --]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, back to index

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-08-21 19:29 [PATCH 0/3] pci: add support for firmware initialized designware RCs Ard Biesheuvel
2017-08-21 19:29 ` [PATCH 1/3] pci: designware: add driver for DWC controller in ECAM shift mode Ard Biesheuvel
2017-08-24 16:24   ` kbuild test robot
2017-08-24 16:25   ` kbuild test robot

Linux-PCI Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-pci/0 linux-pci/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-pci linux-pci/ https://lore.kernel.org/linux-pci \
		linux-pci@vger.kernel.org
	public-inbox-index linux-pci

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-pci


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git