Re: [PATCH 4/5] PCI: iproc: Add iProc PCIe MSI support

From: Ray Jui
Date: Thu Nov 19 2015 - 02:23:54 EST

Hi Marc,

On 11/18/2015 5:37 PM, Ray Jui wrote:
Hi Marc,

On 11/18/2015 12:48 AM, Marc Zyngier wrote:
On Tue, 17 Nov 2015 16:31:54 -0800
Ray Jui <rjui@xxxxxxxxxxxx> wrote:

Hi Ray,

A few comments below.

This patch adds PCIe MSI support for both PAXB and PAXC interfaces on
all iProc based platforms. The patch follows the latest trend in the
kernel to use MSI domain based implementation

This iProc event queue based MSI support should not be used with newer
platforms with integrated MSI support in the GIC (e.g., giv2m or
gicv3-its)

Signed-off-by: Ray Jui <rjui@xxxxxxxxxxxx>
Reviewed-by: Anup Patel <anup.patel@xxxxxxxxxxxx>
Reviewed-by: Vikram Prakash <vikramp@xxxxxxxxxxxx>
Reviewed-by: Scott Branden <sbranden@xxxxxxxxxxxx>
---
drivers/pci/host/Kconfig | 9 +
drivers/pci/host/Makefile | 1 +
drivers/pci/host/pcie-iproc-msi.c | 434
++++++++++++++++++++++++++++++++++++++
drivers/pci/host/pcie-iproc.c | 19 ++
drivers/pci/host/pcie-iproc.h | 12 ++
5 files changed, 475 insertions(+)
create mode 100644 drivers/pci/host/pcie-iproc-msi.c

diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index f131ba9..972e906 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -126,6 +126,15 @@ config PCIE_IPROC
iProc family of SoCs. An appropriate bus interface driver
also needs
to be enabled

+config PCIE_IPROC_MSI
+ bool "Broadcom iProc PCIe MSI support"
+ depends on ARCH_BCM_IPROC && PCI_MSI
+ select PCI_MSI_IRQ_DOMAIN
+ default ARCH_BCM_IPROC
+ help
+ Say Y here if you want to enable MSI support for Broadcom's iProc
+ PCIe controller
+
config PCIE_IPROC_PLATFORM
tristate "Broadcom iProc PCIe platform bus driver"
depends on ARCH_BCM_IPROC || (ARM && COMPILE_TEST)
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index 9d4d3c6..0e4e95e 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_PCI_XGENE_MSI) += pci-xgene-msi.o
obj-$(CONFIG_PCI_LAYERSCAPE) += pci-layerscape.o
obj-$(CONFIG_PCI_VERSATILE) += pci-versatile.o
obj-$(CONFIG_PCIE_IPROC) += pcie-iproc.o
+obj-$(CONFIG_PCIE_IPROC_MSI) += pcie-iproc-msi.o
obj-$(CONFIG_PCIE_IPROC_PLATFORM) += pcie-iproc-platform.o
obj-$(CONFIG_PCIE_IPROC_BCMA) += pcie-iproc-bcma.o
obj-$(CONFIG_PCIE_ALTERA) += pcie-altera.o
diff --git a/drivers/pci/host/pcie-iproc-msi.c
b/drivers/pci/host/pcie-iproc-msi.c
new file mode 100644
index 0000000..a55c707
--- /dev/null
+++ b/drivers/pci/host/pcie-iproc-msi.c
@@ -0,0 +1,434 @@
+/*
+ * Copyright (C) 2015 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/msi.h>
+#include <linux/of_irq.h>
+#include <linux/of_pci.h>
+#include <linux/pci.h>
+
+#include "pcie-iproc.h"
+
+#define IPROC_MSI_INTS_EN_OFFSET 0x208
+#define IPROC_MSI_INTR_EN_SHIFT 11
+#define IPROC_MSI_INTR_EN BIT(IPROC_MSI_INTR_EN_SHIFT)
+#define IPROC_MSI_INT_N_EVENT_SHIFT 1
+#define IPROC_MSI_INT_N_EVENT BIT(IPROC_MSI_INT_N_EVENT_SHIFT)
+#define IPROC_MSI_EQ_EN_SHIFT 0
+#define IPROC_MSI_EQ_EN BIT(IPROC_MSI_EQ_EN_SHIFT)
+
+#define IPROC_MSI_EQ_MASK 0x3f
+
+/* number of queues in each event queue */
+#define IPROC_MSI_EQ_LEN 64
+
+/* size of each event queue memory region */
+#define EQ_MEM_REGION_SIZE SZ_4K
+
+/* size of each MSI message memory region */
+#define MSI_MSG_MEM_REGION_SIZE SZ_4K
+
+enum iproc_msi_reg {
+ IPROC_MSI_EQ_PAGE = 0,
+ IPROC_MSI_EQ_PAGE_UPPER,
+ IPROC_MSI_PAGE,
+ IPROC_MSI_PAGE_UPPER,
+ IPROC_MSI_CTRL,
+ IPROC_MSI_EQ_HEAD,
+ IPROC_MSI_EQ_TAIL,
+ IPROC_MSI_REG_SIZE,
+};
+
+/**
+ * iProc event queue based MSI
+ *
+ * Only meant to be used on platforms without MSI support integrated
into the
+ * GIC
+ *
+ * @pcie: pointer to iProc PCIe data
+ * @reg_offsets: MSI register offsets
+ * @irqs: pointer to an array that contains the interrupt IDs
+ * @nirqs: number of total interrupts
+ * @has_inten_reg: indicates the MSI interrupt enable register needs
to be
+ * set explicitly (required for some legacy platforms)
+ * @used: bitmap to track usage of MSI
+ * @inner_domain: inner IRQ domain
+ * @msi_domain: MSI IRQ domain
+ * @bitmap_lock: lock to protect access to the IRQ bitmap
+ * @n_eq_region: required number of 4K aligned memory region for MSI
event
+ * queues
+ * @n_msi_msg_region: required number of 4K aligned memory region
for MSI
+ * posted writes
+ * @eq_base: pointer to allocated memory region for MSI event queues
+ * @msi_base: pointer to allocated memory region for MSI posted writes
+ */
+struct iproc_msi {
+ struct iproc_pcie *pcie;
+ const u16 (*reg_offsets)[IPROC_MSI_REG_SIZE];
+ int *irqs;
+ int nirqs;
+ bool has_inten_reg;
+ DECLARE_BITMAP(used, IPROC_PCIE_MAX_NUM_IRQS);
+ struct irq_domain *inner_domain;
+ struct irq_domain *msi_domain;
+ struct mutex bitmap_lock;
+ unsigned int n_eq_region;
+ unsigned int n_msi_msg_region;
+ void *eq_base;
+ void *msi_base;
+};
+
+static const u16
+iproc_msi_reg_paxb[IPROC_PCIE_MAX_NUM_IRQS][IPROC_MSI_REG_SIZE] = {
+ { 0x200, 0x2c0, 0x204, 0x2c4, 0x210, 0x250, 0x254 },
+ { 0x200, 0x2c0, 0x204, 0x2c4, 0x214, 0x258, 0x25c },
+ { 0x200, 0x2c0, 0x204, 0x2c4, 0x218, 0x260, 0x264 },
+ { 0x200, 0x2c0, 0x204, 0x2c4, 0x21c, 0x268, 0x26c },
+ { 0x200, 0x2c0, 0x204, 0x2c4, 0x220, 0x270, 0x274 },
+ { 0x200, 0x2c0, 0x204, 0x2c4, 0x224, 0x278, 0x27c },
+};
+
+static const u16
+iproc_msi_reg_paxc[IPROC_PCIE_MAX_NUM_IRQS][IPROC_MSI_REG_SIZE] = {
+ { 0xc00, 0xc04, 0xc08, 0xc0c, 0xc40, 0xc50, 0xc60 },
+ { 0xc10, 0xc14, 0xc18, 0xc1c, 0xc44, 0xc54, 0xc64 },
+ { 0xc20, 0xc24, 0xc28, 0xc2c, 0xc48, 0xc58, 0xc68 },
+ { 0xc30, 0xc34, 0xc38, 0xc3c, 0xc4c, 0xc5c, 0xc6c },
+};
+
+static inline u32 iproc_msi_read_reg(struct iproc_msi *msi,
+ enum iproc_msi_reg reg,
+ unsigned int eq)
+{
+ struct iproc_pcie *pcie = msi->pcie;
+
+ return readl(pcie->base + msi->reg_offsets[eq][reg]);

Do you need the extra barrier implied by readl? readl_relaxed should be
enough.

+}
+
+static inline void iproc_msi_write_reg(struct iproc_msi *msi,
+ enum iproc_msi_reg reg,
+ int eq, u32 val)
+{
+ struct iproc_pcie *pcie = msi->pcie;
+
+ writel(val, pcie->base + msi->reg_offsets[eq][reg]);

Same here for writel vs writel_relaxed.


I probably do not need the barrier in most cases. But as we are dealing
with MSI, I thought it's a lot safer to have the barrier in place so the
CPU does not re-order the device register accesses with respect to other
memory accesses?

+}
+
+static struct irq_chip iproc_msi_top_irq_chip = {
+ .name = "iProc MSI",
+ .irq_enable = pci_msi_unmask_irq,
+ .irq_disable = pci_msi_mask_irq,
+ .irq_mask = pci_msi_mask_irq,
+ .irq_unmask = pci_msi_unmask_irq,

There is no need to provide both enable/disable and mask/unmask. And
since pci_msi_{un}mask_irq is the default, you can get rid of these
function pointers anyway.


Got it. Like you said, the mask/unmask callback are defaulted to
pci_msi_{un}mask_irq in pci_msi_domain_update_chip_ops, called when the
MSI irq domain is created.

I'll get rid of all the callback assignments here.

+};
+
+static struct msi_domain_info iproc_msi_domain_info = {
+ .flags = MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+ MSI_FLAG_PCI_MSIX,
+ .chip = &iproc_msi_top_irq_chip,
+};
+
+static int iproc_msi_irq_set_affinity(struct irq_data *data,
+ const struct cpumask *mask, bool force)
+{
+ return -EINVAL;

I wish people would stop building stupid HW that prevents proper
affinity setting for MSI...


In fact, there's no reason why the HW should prevent us from setting the
MSI affinity. This is currently more of a SW issue that I have not spent
enough time figuring out.

Here's my understanding:

In our system, each MSI is linked to a dedicated interrupt line
connected to the GIC upstream (e.g., the GIC from Cortex A9 in Cygnus).

Okay I need to take my words back. I just had a long meeting with our ASIC engineer. In fact, we are supposed to be able to support up to 64 MSI vectors per GIC interrupt line.

Correct me if I'm wrong, to get the MSI affinity to work, all I need
should be propagating the affinity setting to the GIC (the 1-to-1
mapping helps simply things quite a bit here)?

Now MSI affinity gets much more complicated and I'm not sure how the HW can support it. I need more meetings with our ASIC engineers to figure this out. I'm not planning to support MSI IRQ affinity at this point.


I tried to hook this up with irq_chip_set_affinity_parent. But it looks
like the irq chip of the parent domain (i.e., the GIC) is pointing to
NULL, and therefore it would crash when dereferencing it to get the
irq_set_affinity callback.

I thought I did everything required by figuring out and linking to the
correct parent domain in the iproc_msi_init routine:

parent_node = of_parse_phandle(node, "interrupt-parent", 0);
if (!parent_node) {
dev_err(pcie->dev, "unable to parse MSI interrupt parent\n");
return -ENODEV;
}

parent_domain = irq_find_host(parent_node);
if (!parent_domain) {
dev_err(pcie->dev, "unable to get MSI parent domain\n");
return -ENODEV;
}

...
...

msi->inner_domain = irq_domain_add_hierarchy(parent_domain, 0,
msi->nirqs, NULL,
&msi_domain_ops,
msi);

I haven't spent too much time investigating, and am hoping to eventually
enable affinity support with an incremental patch in the future when I
have more time to investigate.

+}
+
+static void iproc_msi_irq_compose_msi_msg(struct irq_data *data,
+ struct msi_msg *msg)
+{
+ struct iproc_msi *msi = irq_data_get_irq_chip_data(data);
+ phys_addr_t addr;
+
+ addr = virt_to_phys(msi->msi_base) | (data->hwirq * 4);
+ msg->address_lo = lower_32_bits(addr);
+ msg->address_hi = upper_32_bits(addr);
+ msg->data = data->hwirq;
+}
+
+static struct irq_chip iproc_msi_bottom_irq_chip = {
+ .name = "MSI",
+ .irq_set_affinity = iproc_msi_irq_set_affinity,
+ .irq_compose_msi_msg = iproc_msi_irq_compose_msi_msg,
+};
+
+static int iproc_msi_irq_domain_alloc(struct irq_domain *domain,
+ unsigned int virq, unsigned int nr_irqs,
+ void *args)
+{
+ struct iproc_msi *msi = domain->host_data;
+ int i, msi_irq;
+
+ mutex_lock(&msi->bitmap_lock);
+
+ for (i = 0; i < nr_irqs; i++) {
+ msi_irq = find_first_zero_bit(msi->used, msi->nirqs);

This is slightly puzzling. Do you really have at most 6 MSIs? Usually,
we end up with a larger number of MSIs (32 or 64) multiplexed on top of
a small number of wired interrupts. Here, you seem to have a 1-1
mapping. Is that really the case?

Yes, based on the poorly written iProc PCIe arch doc, :), we seem to
have 1-1 mapping between each wired interrupt and MSI, with each MSI
handled by an event queue, that consists of 64x word entries allocated
from host memory (DDR). The MSI data is stored in the low 16-bit of each
entry, whereas the upper 16-bit of each entry is reserved for the iProc
PCIe controller for its own use.


So yeah, you are right. We should be able to support up to 64 MSI vectors per interrupt. This is just embarrassing.... :(

And thanks for pointing this out.


If so (and assuming the wired interrupts are always contiguous), you
shouldn't represent this as a chained interrupt (a multiplexer), but as
a stacked irqchip, similar to what GICv2m does.


Okay, I think I might be missing something here, but I thought I
currently have a stacked irqdomain (chip), i.e., GIC -> inner_domain ->
MSI domain?

And does this imply I should expect 'nr_irqs' in this routine to be
always zero and therefore I can get rid of the for loop here (same in
the domain free routine)?

And yeah, chained IRQ will be used for all MSI vectors in each interrupt line.


+ if (msi_irq < msi->nirqs) {
+ set_bit(msi_irq, msi->used);
+ } else {
+ mutex_unlock(&msi->bitmap_lock);
+ return -ENOSPC;
+ }
+
+ irq_domain_set_info(domain, virq + i, msi_irq,
+ &iproc_msi_bottom_irq_chip,
+ domain->host_data, handle_simple_irq,
+ NULL, NULL);
+ }
+
+ mutex_unlock(&msi->bitmap_lock);
+ return 0;
+}
+
+static void iproc_msi_irq_domain_free(struct irq_domain *domain,
+ unsigned int virq, unsigned int nr_irqs)
+{
+ struct irq_data *data = irq_domain_get_irq_data(domain, virq);
+ struct iproc_msi *msi = irq_data_get_irq_chip_data(data);
+ unsigned int i;
+
+ mutex_lock(&msi->bitmap_lock);
+
+ for (i = 0; i < nr_irqs; i++) {
+ struct irq_data *data = irq_domain_get_irq_data(domain,
+ virq + i);
+ if (!test_bit(data->hwirq, msi->used)) {
+ dev_warn(msi->pcie->dev, "freeing unused MSI %lu\n",
+ data->hwirq);
+ } else
+ clear_bit(data->hwirq, msi->used);
+ }
+
+ mutex_unlock(&msi->bitmap_lock);
+ irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+}
+
+static const struct irq_domain_ops msi_domain_ops = {
+ .alloc = iproc_msi_irq_domain_alloc,
+ .free = iproc_msi_irq_domain_free,
+};
+
+static void iproc_msi_enable(struct iproc_msi *msi)
+{
+ struct iproc_pcie *pcie = msi->pcie;
+ int i, eq;
+ u32 val;
+
+ /* program memory region for each event queue */
+ for (i = 0; i < msi->n_eq_region; i++) {
+ phys_addr_t addr =
+ virt_to_phys(msi->eq_base + (i * EQ_MEM_REGION_SIZE));
+
+ iproc_msi_write_reg(msi, IPROC_MSI_EQ_PAGE, i,
+ lower_32_bits(addr));
+ iproc_msi_write_reg(msi, IPROC_MSI_EQ_PAGE_UPPER, i,
+ upper_32_bits(addr));
+ }
+
+ /* program memory region for MSI posted writes */
+ for (i = 0; i < msi->n_msi_msg_region; i++) {
+ phys_addr_t addr =
+ virt_to_phys(msi->msi_base +
+ (i * MSI_MSG_MEM_REGION_SIZE));

You seem to be a victim of checkpatch. Please don't split statements
like this, it just make it harder to read. My terminal can wrap lines
very conveniently, and I don't care about the 80 character limit...


Okay will fix.

+
+ iproc_msi_write_reg(msi, IPROC_MSI_PAGE, i,
+ lower_32_bits(addr));
+ iproc_msi_write_reg(msi, IPROC_MSI_PAGE_UPPER, i,
+ upper_32_bits(addr));
+ }
+
+ for (eq = 0; eq < msi->nirqs; eq++) {
+ /* enable MSI event queue */
+ val = IPROC_MSI_INTR_EN | IPROC_MSI_INT_N_EVENT |
+ IPROC_MSI_EQ_EN;
+ iproc_msi_write_reg(msi, IPROC_MSI_CTRL, eq, val);
+
+ /*
+ * Some legacy platforms require the MSI interrupt enable
+ * register to be set explicitly
+ */
+ if (msi->has_inten_reg) {
+ val = readl(pcie->base + IPROC_MSI_INTS_EN_OFFSET);
+ val |= BIT(eq);
+ writel(val, pcie->base + IPROC_MSI_INTS_EN_OFFSET);
+ }
+ }
+}
+
+static void iproc_msi_handler(struct irq_desc *desc)
+{
+ unsigned int irq = irq_desc_get_irq(desc);
+ struct irq_chip *irq_chip = irq_desc_get_chip(desc);
+ struct iproc_msi *msi;
+ struct iproc_pcie *pcie;
+ u32 eq, head, tail, num_events;
+ int virq;
+
+ chained_irq_enter(irq_chip, desc);
+
+ msi = irq_get_handler_data(irq);
+ pcie = msi->pcie;
+
+ eq = irq - msi->irqs[0];
+ virq = irq_find_mapping(msi->inner_domain, eq);
+ head = iproc_msi_read_reg(msi, IPROC_MSI_EQ_HEAD, eq) &
+ IPROC_MSI_EQ_MASK;
+ do {
+ tail = iproc_msi_read_reg(msi, IPROC_MSI_EQ_TAIL, eq) &
+ IPROC_MSI_EQ_MASK;
+
+ num_events = (tail < head) ?
+ (IPROC_MSI_EQ_LEN - (head - tail)) : (tail - head);
+ if (!num_events)
+ break;
+
+ generic_handle_irq(virq);
+
+ head++;
+ head %= IPROC_MSI_EQ_LEN;
+ iproc_msi_write_reg(msi, IPROC_MSI_EQ_HEAD, eq, head);
+ } while (true);

That's unusual. You seem to get only one interrupt for a bunch of MSIs,
all representing the same IRQ? That feels very weird, as you can
usually collapse edge interrupts.


I think we get one GIC interrupt per MSI line (1:1 mapping), but then
the MSI data message can be more than one, stored in the event queue
reserved for that MSI/interrupt line.

When you mentioned chained IRQ above, do you really mean the logic here?
In fact, I don't think I really need to use the chained irq APIs here,
as the MSI and GIC interrupt line has a 1-to-1 mapping.


The above routine needs to be modified to:

go through the event queue and identify each MSI vector to be serviced, and service them by calling generic_handle_irq.

+
+ chained_irq_exit(irq_chip, desc);
+}
+

Can probably get rid of the chained_irq_enter and exit?

+int iproc_msi_init(struct iproc_pcie *pcie, struct device_node *node)
+{
+ struct iproc_msi *msi;
+ struct device_node *parent_node;
+ struct irq_domain *parent_domain;
+ int i, ret;
+
+ if (!of_device_is_compatible(node, "brcm,iproc-msi"))
+ return -ENODEV;
+
+ if (!of_find_property(node, "msi-controller", NULL))
+ return -ENODEV;
+
+ parent_node = of_parse_phandle(node, "interrupt-parent", 0);
+ if (!parent_node) {
+ dev_err(pcie->dev, "unable to parse MSI interrupt parent\n");
+ return -ENODEV;
+ }
+
+ parent_domain = irq_find_host(parent_node);
+ if (!parent_domain) {
+ dev_err(pcie->dev, "unable to get MSI parent domain\n");
+ return -ENODEV;
+ }
+
+ msi = devm_kzalloc(pcie->dev, sizeof(*msi), GFP_KERNEL);
+ if (!msi)
+ return -ENOMEM;
+
+ msi->pcie = pcie;
+ mutex_init(&msi->bitmap_lock);
+
+ switch (pcie->type) {
+ case IPROC_PCIE_PAXB:
+ msi->reg_offsets = iproc_msi_reg_paxb;
+ break;
+ case IPROC_PCIE_PAXC:
+ msi->reg_offsets = iproc_msi_reg_paxc;
+ break;
+ default:
+ dev_err(pcie->dev, "incompatible iProc PCIe interface\n");
+ return -EINVAL;
+ }
+
+ ret = of_property_read_u32(node, "brcm,num-eq-region",
+ &msi->n_eq_region);
+ if (ret || msi->n_eq_region == 0) {
+ dev_err(pcie->dev,
+ "invalid property 'brcm,num-eq-region' %u\n",
+ msi->n_eq_region);
+ return -ENODEV;
+ }
+
+ ret = of_property_read_u32(node, "brcm,num-msi-msg-region",
+ &msi->n_msi_msg_region);
+ if (ret || msi->n_msi_msg_region == 0) {
+ dev_err(pcie->dev,
+ "invalid property 'brcm,num-msi-msg-region' %u\n",
+ msi->n_msi_msg_region);
+ return -ENODEV;
+ }
+
+ /* reserve memory for MSI event queue */
+ msi->eq_base = devm_kcalloc(pcie->dev, msi->n_eq_region + 1,
+ EQ_MEM_REGION_SIZE, GFP_KERNEL);
+ if (!msi->eq_base)
+ return -ENOMEM;
+ msi->eq_base = PTR_ALIGN(msi->eq_base, EQ_MEM_REGION_SIZE);
+
+ /* reserve memory for MSI posted writes */
+ msi->msi_base = devm_kcalloc(pcie->dev, msi->n_msi_msg_region + 1,
+ MSI_MSG_MEM_REGION_SIZE, GFP_KERNEL);
+ if (!msi->msi_base)
+ return -ENOMEM;
+ msi->msi_base = PTR_ALIGN(msi->msi_base, MSI_MSG_MEM_REGION_SIZE);
+
+ if (of_find_property(node, "brcm,pcie-msi-inten", NULL))
+ msi->has_inten_reg = true;
+
+ msi->nirqs = of_irq_count(node);
+ if (!msi->nirqs) {
+ dev_err(pcie->dev, "found no MSI interrupt in DT\n");
+ return -ENODEV;
+ }
+ if (msi->nirqs > IPROC_PCIE_MAX_NUM_IRQS) {
+ dev_warn(pcie->dev, "too many MSI interrupts defined %d\n",
+ msi->nirqs);
+ msi->nirqs = IPROC_PCIE_MAX_NUM_IRQS;
+ }
+ msi->irqs = devm_kcalloc(pcie->dev, msi->nirqs, sizeof(*msi->irqs),
+ GFP_KERNEL);
+ if (!msi->irqs)
+ return -ENOMEM;
+
+ for (i = 0; i < msi->nirqs; i++) {
+ msi->irqs[i] = irq_of_parse_and_map(node, i);
+ if (!msi->irqs[i]) {
+ dev_err(pcie->dev, "unable to parse/map interrupt\n");
+ return -ENODEV;
+ }
+ }
+
+ msi->inner_domain = irq_domain_add_hierarchy(parent_domain, 0,
+ msi->nirqs, NULL,
+ &msi_domain_ops,
+ msi);
+ if (!msi->inner_domain) {
+ dev_err(pcie->dev, "failed to create inner domain\n");
+ return -ENOMEM;
+ }
+
+ msi->msi_domain =
pci_msi_create_irq_domain(of_node_to_fwnode(node),
+ &iproc_msi_domain_info,
+ msi->inner_domain);
+ if (!msi->msi_domain) {
+ dev_err(pcie->dev, "failed to create MSI domain\n");
+ irq_domain_remove(msi->inner_domain);
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < msi->nirqs; i++)
+ irq_set_chained_handler_and_data(msi->irqs[i],
+ iproc_msi_handler, msi);
+
+ iproc_msi_enable(msi);
+
+ return 0;
+}
+EXPORT_SYMBOL(iproc_msi_init);

Do you really intend for this to be built as a standalone module?


The iProc MSI driver is statically linked in, but the iProc PCIe core
driver can be built as a module. The EXPORT_SYMBOL here is for
iproc_msi_init to be exported symbol to iProc PCIe core driver when
built as module.

diff --git a/drivers/pci/host/pcie-iproc.c
b/drivers/pci/host/pcie-iproc.c
index 24d5b62..a575ef3 100644
--- a/drivers/pci/host/pcie-iproc.c
+++ b/drivers/pci/host/pcie-iproc.c
@@ -440,6 +440,21 @@ static int iproc_pcie_map_ranges(struct
iproc_pcie *pcie,
return 0;
}

+static int iproc_pcie_msi_enable(struct iproc_pcie *pcie)
+{
+ struct device_node *msi_node;
+
+ msi_node = of_parse_phandle(pcie->dev->of_node, "msi-parent", 0);
+ if (!msi_node)
+ return -ENODEV;
+
+ /*
+ * If another MSI controller is being used, the call below
should fail
+ * but that is okay
+ */
+ return iproc_msi_init(pcie, msi_node);
+}
+
int iproc_pcie_setup(struct iproc_pcie *pcie, struct list_head *res)
{
int ret;
@@ -507,6 +522,10 @@ int iproc_pcie_setup(struct iproc_pcie *pcie,
struct list_head *res)

iproc_pcie_enable(pcie);

+ if (IS_ENABLED(CONFIG_PCI_MSI))
+ if (iproc_pcie_msi_enable(pcie))
+ dev_info(pcie->dev, "not using iProc MSI\n");
+
pci_scan_child_bus(bus);
pci_assign_unassigned_bus_resources(bus);
pci_fixup_irqs(pci_common_swizzle, pcie->map_irq);
diff --git a/drivers/pci/host/pcie-iproc.h
b/drivers/pci/host/pcie-iproc.h
index 051b651..17317ef 100644
--- a/drivers/pci/host/pcie-iproc.h
+++ b/drivers/pci/host/pcie-iproc.h
@@ -14,6 +14,8 @@
#ifndef _PCIE_IPROC_H
#define _PCIE_IPROC_H

+#define IPROC_PCIE_MAX_NUM_IRQS 6
+

I don't see the point in putting this in an include file, as it is only
used in a single location.


Okay. Will move it into pcie-iproc-msi.c

/**
* iProc PCIe interface type
*
@@ -74,4 +76,14 @@ struct iproc_pcie {
int iproc_pcie_setup(struct iproc_pcie *pcie, struct list_head *res);
int iproc_pcie_remove(struct iproc_pcie *pcie);

+#ifdef CONFIG_PCI_MSI
+int iproc_msi_init(struct iproc_pcie *pcie, struct device_node *node);
+#else
+static inline int iproc_msi_init(struct iproc_pcie *pcie,
+ struct device_node *node)
+{
+ return -ENODEV;
+}
+#endif
+
#endif /* _PCIE_IPROC_H */

Thanks,

M.


Thanks a lot for the review. I really appreciate it!

Ray

Thanks,

Ray
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