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Subject[PATCH 09/23] AMD IOMMU: add MSI interrupt support
Date
The AMD IOMMU can generate interrupts for various reasons. This patch
adds the basic interrupt enabling infrastructure to the driver.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
arch/x86/Kconfig | 1 +
arch/x86/kernel/amd_iommu.c | 11 ++++
arch/x86/kernel/amd_iommu_init.c | 99 ++++++++++++++++++++++++++++++++++++-
include/asm-x86/amd_iommu.h | 3 +
include/asm-x86/amd_iommu_types.h | 7 +++
5 files changed, 120 insertions(+), 1 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5258240..9c2898c 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -567,6 +567,7 @@ config CALGARY_IOMMU_ENABLED_BY_DEFAULT
config AMD_IOMMU
bool "AMD IOMMU support"
select SWIOTLB
+ select PCI_MSI
depends on X86_64 && PCI && ACPI
help
With this option you can enable support for AMD IOMMU hardware in
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index fdec963..3caef6b 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -51,6 +51,17 @@ static int iommu_has_npcache(struct amd_iommu *iommu)

/****************************************************************************
*
+ * Interrupt handling functions
+ *
+ ****************************************************************************/
+
+irqreturn_t amd_iommu_int_handler(int irq, void *data)
+{
+ return IRQ_NONE;
+}
+
+/****************************************************************************
+ *
* IOMMU command queuing functions
*
****************************************************************************/
diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index da619fc..ce3130d 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -22,6 +22,8 @@
#include <linux/gfp.h>
#include <linux/list.h>
#include <linux/sysdev.h>
+#include <linux/interrupt.h>
+#include <linux/msi.h>
#include <asm/pci-direct.h>
#include <asm/amd_iommu_types.h>
#include <asm/amd_iommu.h>
@@ -516,17 +518,20 @@ static void __init set_device_exclusion_range(u16 devid, struct ivmd_header *m)
static void __init init_iommu_from_pci(struct amd_iommu *iommu)
{
int cap_ptr = iommu->cap_ptr;
- u32 range;
+ u32 range, misc;

pci_read_config_dword(iommu->dev, cap_ptr + MMIO_CAP_HDR_OFFSET,
&iommu->cap);
pci_read_config_dword(iommu->dev, cap_ptr + MMIO_RANGE_OFFSET,
&range);
+ pci_read_config_dword(iommu->dev, cap_ptr + MMIO_MISC_OFFSET,
+ &misc);

iommu->first_device = calc_devid(MMIO_GET_BUS(range),
MMIO_GET_FD(range));
iommu->last_device = calc_devid(MMIO_GET_BUS(range),
MMIO_GET_LD(range));
+ iommu->evt_msi_num = MMIO_MSI_NUM(misc);
}

/*
@@ -697,6 +702,8 @@ static int __init init_iommu_one(struct amd_iommu *iommu, struct ivhd_header *h)
if (!iommu->evt_buf)
return -ENOMEM;

+ iommu->int_enabled = false;
+
init_iommu_from_pci(iommu);
init_iommu_from_acpi(iommu, h);
init_iommu_devices(iommu);
@@ -744,6 +751,95 @@ static int __init init_iommu_all(struct acpi_table_header *table)

/****************************************************************************
*
+ * The following functions initialize the MSI interrupts for all IOMMUs
+ * in the system. Its a bit challenging because there could be multiple
+ * IOMMUs per PCI BDF but we can call pci_enable_msi(x) only once per
+ * pci_dev.
+ *
+ ****************************************************************************/
+
+static int __init iommu_setup_msix(struct amd_iommu *iommu)
+{
+ struct amd_iommu *curr;
+ struct msix_entry entries[32]; /* only 32 supported by AMD IOMMU */
+ int nvec = 0, i;
+
+ list_for_each_entry(curr, &amd_iommu_list, list) {
+ if (curr->dev == iommu->dev) {
+ entries[nvec].entry = curr->evt_msi_num;
+ entries[nvec].vector = 0;
+ curr->int_enabled = true;
+ nvec++;
+ }
+ }
+
+ if (pci_enable_msix(iommu->dev, entries, nvec)) {
+ pci_disable_msix(iommu->dev);
+ return 1;
+ }
+
+ for (i = 0; i < nvec; ++i) {
+ int r = request_irq(entries->vector, amd_iommu_int_handler,
+ IRQF_SAMPLE_RANDOM,
+ "AMD IOMMU",
+ NULL);
+ if (r)
+ goto out_free;
+ }
+
+ return 0;
+
+out_free:
+ for (i -= 1; i >= 0; --i)
+ free_irq(entries->vector, NULL);
+
+ pci_disable_msix(iommu->dev);
+
+ return 1;
+}
+
+static int __init iommu_setup_msi(struct amd_iommu *iommu)
+{
+ int r;
+ struct amd_iommu *curr;
+
+ list_for_each_entry(curr, &amd_iommu_list, list) {
+ if (curr->dev == iommu->dev)
+ curr->int_enabled = true;
+ }
+
+
+ if (pci_enable_msi(iommu->dev))
+ return 1;
+
+ r = request_irq(iommu->dev->irq, amd_iommu_int_handler,
+ IRQF_SAMPLE_RANDOM,
+ "AMD IOMMU",
+ NULL);
+
+ if (r) {
+ pci_disable_msi(iommu->dev);
+ return 1;
+ }
+
+ return 0;
+}
+
+static int __init iommu_init_msi(struct amd_iommu *iommu)
+{
+ if (iommu->int_enabled)
+ return 0;
+
+ if (pci_find_capability(iommu->dev, PCI_CAP_ID_MSIX))
+ return iommu_setup_msix(iommu);
+ else if (pci_find_capability(iommu->dev, PCI_CAP_ID_MSI))
+ return iommu_setup_msi(iommu);
+
+ return 1;
+}
+
+/****************************************************************************
+ *
* The next functions belong to the third pass of parsing the ACPI
* table. In this last pass the memory mapping requirements are
* gathered (like exclusion and unity mapping reanges).
@@ -863,6 +959,7 @@ static void __init enable_iommus(void)

list_for_each_entry(iommu, &amd_iommu_list, list) {
iommu_set_exclusion_range(iommu);
+ iommu_init_msi(iommu);
iommu_enable(iommu);
}
}
diff --git a/include/asm-x86/amd_iommu.h b/include/asm-x86/amd_iommu.h
index 783f43e..041d0db 100644
--- a/include/asm-x86/amd_iommu.h
+++ b/include/asm-x86/amd_iommu.h
@@ -20,10 +20,13 @@
#ifndef ASM_X86__AMD_IOMMU_H
#define ASM_X86__AMD_IOMMU_H

+#include <linux/irqreturn.h>
+
#ifdef CONFIG_AMD_IOMMU
extern int amd_iommu_init(void);
extern int amd_iommu_init_dma_ops(void);
extern void amd_iommu_detect(void);
+extern irqreturn_t amd_iommu_int_handler(int irq, void *data);
#else
static inline int amd_iommu_init(void) { return -ENODEV; }
static inline void amd_iommu_detect(void) { }
diff --git a/include/asm-x86/amd_iommu_types.h b/include/asm-x86/amd_iommu_types.h
index 58c80f0..6ed8ffa 100644
--- a/include/asm-x86/amd_iommu_types.h
+++ b/include/asm-x86/amd_iommu_types.h
@@ -37,6 +37,7 @@
/* Capability offsets used by the driver */
#define MMIO_CAP_HDR_OFFSET 0x00
#define MMIO_RANGE_OFFSET 0x0c
+#define MMIO_MISC_OFFSET 0x10

/* Masks, shifts and macros to parse the device range capability */
#define MMIO_RANGE_LD_MASK 0xff000000
@@ -48,6 +49,7 @@
#define MMIO_GET_LD(x) (((x) & MMIO_RANGE_LD_MASK) >> MMIO_RANGE_LD_SHIFT)
#define MMIO_GET_FD(x) (((x) & MMIO_RANGE_FD_MASK) >> MMIO_RANGE_FD_SHIFT)
#define MMIO_GET_BUS(x) (((x) & MMIO_RANGE_BUS_MASK) >> MMIO_RANGE_BUS_SHIFT)
+#define MMIO_MSI_NUM(x) ((x) & 0x1f)

/* Flag masks for the AMD IOMMU exclusion range */
#define MMIO_EXCL_ENABLE_MASK 0x01ULL
@@ -255,10 +257,15 @@ struct amd_iommu {
u8 *evt_buf;
/* size of event buffer */
u32 evt_buf_size;
+ /* MSI number for event interrupt */
+ u16 evt_msi_num;

/* if one, we need to send a completion wait command */
int need_sync;

+ /* true if interrupts for this IOMMU are already enabled */
+ bool int_enabled;
+
/* default dma_ops domain for that IOMMU */
struct dma_ops_domain *default_dom;
};
--
1.5.6.4



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