LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Jeremy Linton <jeremy.linton@arm.com>
To: linux-pci@vger.kernel.org
Cc: lorenzo.pieralisi@arm.com, nsaenz@kernel.org,
	bhelgaas@google.com, rjw@rjwysocki.net, lenb@kernel.org,
	robh@kernel.org, kw@linux.com, f.fainelli@gmail.com,
	sdonthineni@nvidia.com, stefan.wahren@i2se.com,
	bcm-kernel-feedback-list@broadcom.com,
	linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-rpi-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Jeremy Linton <jeremy.linton@arm.com>
Subject: [PATCH v2 2/4] PCI: brcmstb: Add ACPI config space quirk
Date: Thu, 19 Aug 2021 16:56:53 -0500	[thread overview]
Message-ID: <20210819215655.84866-3-jeremy.linton@arm.com> (raw)
In-Reply-To: <20210819215655.84866-1-jeremy.linton@arm.com>

The PFTF CM4 is an ACPI platform that isn't ECAM compliant. Its config
space is in two parts. One part is for the root port registers and a
second moveable window pointing at a device's 4K config space. Thus it
doesn't have an MCFG, and any MCFG provided would be nonsense
anyway. Instead, a Linux specific host bridge _DSD selects a custom
ECAM ops and cfgres. The cfg op picks between those two regions while
disallowing problematic accesses.

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
---
 drivers/pci/controller/Makefile            |  1 +
 drivers/pci/controller/pcie-brcmstb-acpi.c | 74 ++++++++++++++++++++++
 include/linux/pci-ecam.h                   |  1 +
 3 files changed, 76 insertions(+)
 create mode 100644 drivers/pci/controller/pcie-brcmstb-acpi.c

diff --git a/drivers/pci/controller/Makefile b/drivers/pci/controller/Makefile
index aaf30b3dcc14..65aa6fd3ed89 100644
--- a/drivers/pci/controller/Makefile
+++ b/drivers/pci/controller/Makefile
@@ -57,5 +57,6 @@ ifdef CONFIG_PCI_QUIRKS
 obj-$(CONFIG_ARM64) += pci-thunder-ecam.o
 obj-$(CONFIG_ARM64) += pci-thunder-pem.o
 obj-$(CONFIG_ARM64) += pci-xgene.o
+obj-$(CONFIG_ARM64) += pcie-brcmstb-acpi.o
 endif
 endif
diff --git a/drivers/pci/controller/pcie-brcmstb-acpi.c b/drivers/pci/controller/pcie-brcmstb-acpi.c
new file mode 100644
index 000000000000..71f6def3074c
--- /dev/null
+++ b/drivers/pci/controller/pcie-brcmstb-acpi.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * ACPI quirks for Brcm2711 PCIe host controller
+ * As used on the Raspberry Pi Compute Module 4
+ *
+ * Copyright (C) 2021 Arm Ltd.
+ */
+
+#include <linux/io.h>
+#include <linux/pci.h>
+#include <linux/pci-ecam.h>
+#include "../pci.h"
+#include "pcie-brcmstb.h"
+
+static int brcm_acpi_init(struct pci_config_window *cfg)
+{
+	/*
+	 * This platform doesn't technically have anything that could be called
+	 * ECAM. Its config region has root port specific registers between
+	 * standard PCIe defined config registers. Thus the region setup by the
+	 * generic ECAM code needs to be adjusted. The HW can access bus 0-ff
+	 * but the footprint isn't a nice power of 2 (40k). For purposes of
+	 * mapping the config region we are just going to squash the standard
+	 * and nonstandard registers together rather than mapping them separately.
+	 */
+	iounmap(cfg->win);
+	cfg->win = pci_remap_cfgspace(cfg->res.start, resource_size(&cfg->res));
+	if (!cfg->win)
+		goto err_exit;
+
+	/* MSI is nonstandard as well */
+	pci_no_msi();
+
+	return 0;
+err_exit:
+	dev_err(cfg->parent, "PCI: Failed to remap config\n");
+	return -ENOMEM;
+}
+
+static void __iomem *brcm_pcie_map_conf2(struct pci_bus *bus,
+					unsigned int devfn, int where)
+{
+	struct pci_config_window *cfg = bus->sysdata;
+	void __iomem *base = cfg->win;
+	int idx;
+	u32 up;
+
+	/* Accesses to the RC go right to the RC registers if slot==0 */
+	if (pci_is_root_bus(bus))
+		return PCI_SLOT(devfn) ? NULL : base + where;
+
+	/* Assure link up before sending request */
+	up = readl(base + PCIE_MISC_PCIE_STATUS);
+	if (!(up & PCIE_MISC_PCIE_STATUS_PCIE_DL_ACTIVE_MASK))
+		return NULL;
+
+	if (!(up & PCIE_MISC_PCIE_STATUS_PCIE_PHYLINKUP_MASK))
+		return NULL;
+
+	/* For devices, write to the config space index register */
+	idx = PCIE_ECAM_OFFSET(bus->number, devfn, 0);
+	writel(idx, base + PCIE_EXT_CFG_INDEX);
+	return base + PCIE_EXT_CFG_DATA + where;
+}
+
+const struct pci_ecam_ops bcm2711_pcie_ops = {
+	.init		= brcm_acpi_init,
+	.bus_shift	= 1,
+	.pci_ops	= {
+		.map_bus	= brcm_pcie_map_conf2,
+		.read		= pci_generic_config_read,
+		.write		= pci_generic_config_write,
+	}
+};
diff --git a/include/linux/pci-ecam.h b/include/linux/pci-ecam.h
index adea5a4771cf..a5de0285bb7f 100644
--- a/include/linux/pci-ecam.h
+++ b/include/linux/pci-ecam.h
@@ -87,6 +87,7 @@ extern const struct pci_ecam_ops xgene_v1_pcie_ecam_ops; /* APM X-Gene PCIe v1 *
 extern const struct pci_ecam_ops xgene_v2_pcie_ecam_ops; /* APM X-Gene PCIe v2.x */
 extern const struct pci_ecam_ops al_pcie_ops;	/* Amazon Annapurna Labs PCIe */
 extern const struct pci_ecam_ops tegra194_pcie_ops; /* Tegra194 PCIe */
+extern const struct pci_ecam_ops bcm2711_pcie_ops; /* Bcm2711 PCIe */
 #endif
 
 #if IS_ENABLED(CONFIG_PCI_HOST_COMMON)
-- 
2.31.1


  parent reply	other threads:[~2021-08-19 21:57 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-19 21:56 [PATCH v2 0/4] CM4 ACPI PCIe quirk Jeremy Linton
2021-08-19 21:56 ` [PATCH v2 1/4] PCI: brcmstb: Break register definitions into separate header Jeremy Linton
2021-08-22  8:49   ` Florian Fainelli
2021-08-19 21:56 ` Jeremy Linton [this message]
2021-08-20 19:06   ` [PATCH v2 2/4] PCI: brcmstb: Add ACPI config space quirk Bjorn Helgaas
2021-08-20 20:31     ` Jeremy Linton
2021-08-22  8:52   ` Florian Fainelli
2021-08-29 11:13   ` Pali Rohár
2021-08-30 16:10     ` Jeremy Linton
2021-08-30 16:54       ` Pali Rohár
2021-08-19 21:56 ` [PATCH v2 3/4] PCI/ACPI: Add Broadcom bcm2711 MCFG quirk Jeremy Linton
2021-08-22  8:53   ` Florian Fainelli
2021-08-24 21:39     ` Jeremy Linton
2021-08-25 16:23       ` Florian Fainelli
2021-08-19 21:56 ` [PATCH v2 4/4] MAINTAINERS: Widen brcmstb PCIe file scope Jeremy Linton
2021-08-20 19:09   ` Bjorn Helgaas
2021-08-22  8:55     ` Florian Fainelli
2021-08-20 19:11 ` [PATCH v2 0/4] CM4 ACPI PCIe quirk Bjorn Helgaas

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210819215655.84866-3-jeremy.linton@arm.com \
    --to=jeremy.linton@arm.com \
    --cc=bcm-kernel-feedback-list@broadcom.com \
    --cc=bhelgaas@google.com \
    --cc=f.fainelli@gmail.com \
    --cc=kw@linux.com \
    --cc=lenb@kernel.org \
    --cc=linux-acpi@vger.kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=linux-rpi-kernel@lists.infradead.org \
    --cc=lorenzo.pieralisi@arm.com \
    --cc=nsaenz@kernel.org \
    --cc=rjw@rjwysocki.net \
    --cc=robh@kernel.org \
    --cc=sdonthineni@nvidia.com \
    --cc=stefan.wahren@i2se.com \
    --subject='Re: [PATCH v2 2/4] PCI: brcmstb: Add ACPI config space quirk' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).