[PATCH v3 1/2] PCI: iproc: Set affinity mask on MSI interrupts

[PATCH v3 1/2] PCI: iproc: Set affinity mask on MSI interrupts

[Mark Tomlinson]

The core interrupt code expects the irq_set_affinity call to update the
effective affinity for the interrupt. This was not being done, so update
iproc_msi_irq_set_affinity() to do so.

Fixes: 3bc2b2348835 ("PCI: iproc: Add iProc PCIe MSI support")
Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
---
changes in v2:
 - Patch 1/2 Added Fixes tag
 - Patch 2/2 Replace original change with change suggested by Bjorn
   Helgaas.

changes in v3:
 - Use bitfield rather than bool to save memory.

 drivers/pci/controller/pcie-iproc-msi.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/controller/pcie-iproc-msi.c b/drivers/pci/controller/pcie-iproc-msi.c
index 3176ad3ab0e5..908475d27e0e 100644
--- a/drivers/pci/controller/pcie-iproc-msi.c
+++ b/drivers/pci/controller/pcie-iproc-msi.c
@@ -209,15 +209,20 @@ static int iproc_msi_irq_set_affinity(struct irq_data *data,
 	struct iproc_msi *msi = irq_data_get_irq_chip_data(data);
 	int target_cpu = cpumask_first(mask);
 	int curr_cpu;
+	int ret;
 
 	curr_cpu = hwirq_to_cpu(msi, data->hwirq);
 	if (curr_cpu == target_cpu)
-		return IRQ_SET_MASK_OK_DONE;
+		ret = IRQ_SET_MASK_OK_DONE;
+	else {
+		/* steer MSI to the target CPU */
+		data->hwirq = hwirq_to_canonical_hwirq(msi, data->hwirq) + target_cpu;
+		ret = IRQ_SET_MASK_OK;
+	}
 
-	/* steer MSI to the target CPU */
-	data->hwirq = hwirq_to_canonical_hwirq(msi, data->hwirq) + target_cpu;
+	irq_data_update_effective_affinity(data, cpumask_of(target_cpu));
 
-	return IRQ_SET_MASK_OK;
+	return ret;
 }
 
 static void iproc_msi_irq_compose_msi_msg(struct irq_data *data,
-- 
2.28.0

[PATCH v3 2/2] PCI: Reduce warnings on possible RW1C corruption

[Mark Tomlinson]

For hardware that only supports 32-bit writes to PCI there is the
possibility of clearing RW1C (write-one-to-clear) bits. A rate-limited
messages was introduced by fb2659230120, but rate-limiting is not the
best choice here. Some devices may not show the warnings they should if
another device has just produced a bunch of warnings. Also, the number
of messages can be a nuisance on devices which are otherwise working
fine.

This patch changes the ratelimit to a single warning per bus. This
ensures no bus is 'starved' of emitting a warning and also that there
isn't a continuous stream of warnings. It would be preferable to have a
warning per device, but the pci_dev structure is not available here, and
a lookup from devfn would be far too slow.

Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
Fixes: fb2659230120 ("PCI: Warn on possible RW1C corruption for sub-32 bit config writes")
Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
---
 drivers/pci/access.c | 9 ++++++---
 include/linux/pci.h  | 1 +
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/access.c b/drivers/pci/access.c
index 79c4a2ef269a..ab85cb7df9b6 100644
--- a/drivers/pci/access.c
+++ b/drivers/pci/access.c
@@ -160,9 +160,12 @@ int pci_generic_config_write32(struct pci_bus *bus, unsigned int devfn,
 	 * write happen to have any RW1C (write-one-to-clear) bits set, we
 	 * just inadvertently cleared something we shouldn't have.
 	 */
-	dev_warn_ratelimited(&bus->dev, "%d-byte config write to %04x:%02x:%02x.%d offset %#x may corrupt adjacent RW1C bits\n",
-			     size, pci_domain_nr(bus), bus->number,
-			     PCI_SLOT(devfn), PCI_FUNC(devfn), where);
+	if (!bus->unsafe_warn) {
+		dev_warn(&bus->dev, "%d-byte config write to %04x:%02x:%02x.%d offset %#x may corrupt adjacent RW1C bits\n",
+			 size, pci_domain_nr(bus), bus->number,
+			 PCI_SLOT(devfn), PCI_FUNC(devfn), where);
+		bus->unsafe_warn = true;
+	}
 
 	mask = ~(((1 << (size * 8)) - 1) << ((where & 0x3) * 8));
 	tmp = readl(addr) & mask;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 34c1c4f45288..5b6ab593ae09 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -613,6 +613,7 @@ struct pci_bus {
 	unsigned char	primary;	/* Number of primary bridge */
 	unsigned char	max_bus_speed;	/* enum pci_bus_speed */
 	unsigned char	cur_bus_speed;	/* enum pci_bus_speed */
+	bool		unsafe_warn;	/* warned about RW1C config write */
 #ifdef CONFIG_PCI_DOMAINS_GENERIC
 	int		domain_nr;
 #endif
-- 
2.28.0

Re: [PATCH v3 1/2] PCI: iproc: Set affinity mask on MSI interrupts

[Ray Jui]

On 8/2/2020 8:52 PM, Mark Tomlinson wrote:
> The core interrupt code expects the irq_set_affinity call to update the
> effective affinity for the interrupt. This was not being done, so update
> iproc_msi_irq_set_affinity() to do so.
> 
> Fixes: 3bc2b2348835 ("PCI: iproc: Add iProc PCIe MSI support")
> Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
> ---
> changes in v2:
>  - Patch 1/2 Added Fixes tag
>  - Patch 2/2 Replace original change with change suggested by Bjorn
>    Helgaas.
> 
> changes in v3:
>  - Use bitfield rather than bool to save memory.
> 
>  drivers/pci/controller/pcie-iproc-msi.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pci/controller/pcie-iproc-msi.c b/drivers/pci/controller/pcie-iproc-msi.c
> index 3176ad3ab0e5..908475d27e0e 100644
> --- a/drivers/pci/controller/pcie-iproc-msi.c
> +++ b/drivers/pci/controller/pcie-iproc-msi.c
> @@ -209,15 +209,20 @@ static int iproc_msi_irq_set_affinity(struct irq_data *data,
>  	struct iproc_msi *msi = irq_data_get_irq_chip_data(data);
>  	int target_cpu = cpumask_first(mask);
>  	int curr_cpu;
> +	int ret;
>  
>  	curr_cpu = hwirq_to_cpu(msi, data->hwirq);
>  	if (curr_cpu == target_cpu)
> -		return IRQ_SET_MASK_OK_DONE;
> +		ret = IRQ_SET_MASK_OK_DONE;
> +	else {
> +		/* steer MSI to the target CPU */
> +		data->hwirq = hwirq_to_canonical_hwirq(msi, data->hwirq) + target_cpu;
> +		ret = IRQ_SET_MASK_OK;
> +	}
>  
> -	/* steer MSI to the target CPU */
> -	data->hwirq = hwirq_to_canonical_hwirq(msi, data->hwirq) + target_cpu;
> +	irq_data_update_effective_affinity(data, cpumask_of(target_cpu));
>  
> -	return IRQ_SET_MASK_OK;
> +	return ret;
>  }
>  
>  static void iproc_msi_irq_compose_msi_msg(struct irq_data *data,
> 

Looks good with the Fixes tag added. Thanks.

Reviewed-by: Ray Jui <ray.jui@broadcom.com>

Re: [PATCH v3 1/2] PCI: iproc: Set affinity mask on MSI interrupts

[Lorenzo Pieralisi]

On Mon, Aug 03, 2020 at 03:52:40PM +1200, Mark Tomlinson wrote:
> The core interrupt code expects the irq_set_affinity call to update the
> effective affinity for the interrupt. This was not being done, so update
> iproc_msi_irq_set_affinity() to do so.
> 
> Fixes: 3bc2b2348835 ("PCI: iproc: Add iProc PCIe MSI support")
> Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
> ---
> changes in v2:
>  - Patch 1/2 Added Fixes tag
>  - Patch 2/2 Replace original change with change suggested by Bjorn
>    Helgaas.
> 
> changes in v3:
>  - Use bitfield rather than bool to save memory.
> 
>  drivers/pci/controller/pcie-iproc-msi.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)

Applied to pci/qcom, thanks.

Lorenzo

> diff --git a/drivers/pci/controller/pcie-iproc-msi.c b/drivers/pci/controller/pcie-iproc-msi.c
> index 3176ad3ab0e5..908475d27e0e 100644
> --- a/drivers/pci/controller/pcie-iproc-msi.c
> +++ b/drivers/pci/controller/pcie-iproc-msi.c
> @@ -209,15 +209,20 @@ static int iproc_msi_irq_set_affinity(struct irq_data *data,
>  	struct iproc_msi *msi = irq_data_get_irq_chip_data(data);
>  	int target_cpu = cpumask_first(mask);
>  	int curr_cpu;
> +	int ret;
>  
>  	curr_cpu = hwirq_to_cpu(msi, data->hwirq);
>  	if (curr_cpu == target_cpu)
> -		return IRQ_SET_MASK_OK_DONE;
> +		ret = IRQ_SET_MASK_OK_DONE;
> +	else {
> +		/* steer MSI to the target CPU */
> +		data->hwirq = hwirq_to_canonical_hwirq(msi, data->hwirq) + target_cpu;
> +		ret = IRQ_SET_MASK_OK;
> +	}
>  
> -	/* steer MSI to the target CPU */
> -	data->hwirq = hwirq_to_canonical_hwirq(msi, data->hwirq) + target_cpu;
> +	irq_data_update_effective_affinity(data, cpumask_of(target_cpu));
>  
> -	return IRQ_SET_MASK_OK;
> +	return ret;
>  }
>  
>  static void iproc_msi_irq_compose_msi_msg(struct irq_data *data,
> -- 
> 2.28.0
>