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Date: Thu, 18 May 2017 11:35:47 +0100
From: Gabriele Paoloni <gabriele.paoloni@...wei.com>
To: <bhelgaas@...gle.com>, <helgaas@...nel.org>
CC: <gabriele.paoloni@...wei.com>, <linuxarm@...wei.com>,
<linux-pci@...r.kernel.org>, <lukas@...ner.de>,
<linux-kernel@...r.kernel.org>, <mika.westerberg@...ux.intel.com>,
<hch@...radead.org>, <liudongdong3@...wei.com>
Subject: [PATCH v3 1/2] PCI/portdrv: add support for different MSI interrupts for PCIe port services
Currently PCIe port services are assigned with different interrutps
only if MSI-x are supported by calling pcie_port_enable_msix().
If a root port supports MSI instead of MSI-x currently we fall back
to use a single shared interrupt for all the services.
This patch renames and extends pcie_port_enable_msix() to use MSI in
case MSI-x allocation fails.
Signed-off-by: Gabriele Paoloni <gabriele.paoloni@...wei.com>
Reviewed-by: Christoph Hellwig <hch@....de>
---
drivers/pci/pcie/portdrv.h | 8 +++++---
drivers/pci/pcie/portdrv_core.c | 43 ++++++++++++++++++++++++-----------------
2 files changed, 30 insertions(+), 21 deletions(-)
diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h
index 587aef3..1993e2c 100644
--- a/drivers/pci/pcie/portdrv.h
+++ b/drivers/pci/pcie/portdrv.h
@@ -13,10 +13,12 @@
#define PCIE_PORT_DEVICE_MAXSERVICES 5
/*
- * According to the PCI Express Base Specification 2.0, the indices of
- * the MSI-X table entries used by port services must not exceed 31
+ * According to the PCI Express Base Specification REV. 3.1 and according
+ * to the PCI Local Bus Specification REV. 3.0 respectively, the indices of
+ * the MSI-X table entries or the max number of MSI vectors used by port
+ * services must not exceed 31
*/
-#define PCIE_PORT_MAX_MSIX_ENTRIES 32
+#define PCIE_PORT_MAX_MSI_ENTRIES 32
#define get_descriptor_id(type, service) (((type - 4) << 8) | service)
diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index cea504f..4d16cf2 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -44,14 +44,15 @@ static void release_pcie_device(struct device *dev)
}
/**
- * pcie_port_enable_msix - try to set up MSI-X as interrupt mode for given port
+ * pcie_port_enable_irq_vec - try to set up MSI-X or MSI as interrupt mode
+ * for given port
* @dev: PCI Express port to handle
* @irqs: Array of interrupt vectors to populate
* @mask: Bitmask of port capabilities returned by get_port_device_capability()
*
* Return value: 0 on success, error code on failure
*/
-static int pcie_port_enable_msix(struct pci_dev *dev, int *irqs, int mask)
+static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
{
int nr_entries, entry, nvec = 0;
@@ -61,8 +62,8 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *irqs, int mask)
* equal to the number of entries this port actually uses, we'll happily
* go through without any tricks.
*/
- nr_entries = pci_alloc_irq_vectors(dev, 1, PCIE_PORT_MAX_MSIX_ENTRIES,
- PCI_IRQ_MSIX);
+ nr_entries = pci_alloc_irq_vectors(dev, 1, PCIE_PORT_MAX_MSI_ENTRIES,
+ PCI_IRQ_MSIX | PCI_IRQ_MSI);
if (nr_entries < 0)
return nr_entries;
@@ -77,7 +78,13 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *irqs, int mask)
* Number field in the PCI Express Capabilities register", where
* according to Section 7.8.2 of the specification "For MSI-X,
* the value in this field indicates which MSI-X Table entry is
- * used to generate the interrupt message."
+ * used to generate the interrupt message." and "For MSI, the
+ * value in this field indicates the offset between the base
+ * Message Data and the interrupt message that is generated."
+ *
+ * pci_irq_vector() below is able to handle entry differently
+ * depending on MSI vs MSI-x case
+ *
*/
pcie_capability_read_word(dev, PCI_EXP_FLAGS, ®16);
entry = (reg16 & PCI_EXP_FLAGS_IRQ) >> 9;
@@ -100,7 +107,10 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *irqs, int mask)
* MSI/MSI-X vectors assigned to the port is going to be used
* for AER, where "For MSI-X, the value in this register
* indicates which MSI-X Table entry is used to generate the
- * interrupt message."
+ * interrupt message." and "For MSI, the value
+ * in this field indicates the offset between the base Message
+ * Data and the interrupt message that is generated."
+ *
*/
pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, ®32);
@@ -124,7 +134,7 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *irqs, int mask)
/* Now allocate the MSI-X vectors for real */
nr_entries = pci_alloc_irq_vectors(dev, nvec, nvec,
- PCI_IRQ_MSIX);
+ PCI_IRQ_MSIX | PCI_IRQ_MSI);
if (nr_entries < 0)
return nr_entries;
}
@@ -146,26 +156,23 @@ static int pcie_port_enable_msix(struct pci_dev *dev, int *irqs, int mask)
*/
static int pcie_init_service_irqs(struct pci_dev *dev, int *irqs, int mask)
{
- unsigned flags = PCI_IRQ_LEGACY | PCI_IRQ_MSI;
int ret, i;
for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
irqs[i] = -1;
/*
- * If MSI cannot be used for PCIe PME or hotplug, we have to use
- * INTx or other interrupts, e.g. system shared interrupt.
+ * Make sure MSI can be used for PCIe PME or hotplug. otherwise we have
+ * to use INTx or other interrupts, e.g. system shared interrupt.
*/
- if (((mask & PCIE_PORT_SERVICE_PME) && pcie_pme_no_msi()) ||
- ((mask & PCIE_PORT_SERVICE_HP) && pciehp_no_msi())) {
- flags &= ~PCI_IRQ_MSI;
- } else {
- /* Try to use MSI-X if supported */
- if (!pcie_port_enable_msix(dev, irqs, mask))
+ if (!((mask & PCIE_PORT_SERVICE_PME) && pcie_pme_no_msi()) &&
+ !((mask & PCIE_PORT_SERVICE_HP) && pciehp_no_msi()))
+ /* Try to use MSI-X or MSI if supported */
+ if (!pcie_port_enable_irq_vec(dev, irqs, mask))
return 0;
- }
- ret = pci_alloc_irq_vectors(dev, 1, 1, flags);
+ /* fall back to legacy IRQ */
+ ret = pci_alloc_irq_vectors(dev, 1, 1, PCI_IRQ_LEGACY);
if (ret < 0)
return -ENODEV;
--
2.7.4
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