diff mbox series

[v13,4/7] PCI: dwc: Handle MSIs routed to multiple GIC interrupts

Message ID 20220603074137.1849892-5-dmitry.baryshkov@linaro.org (mailing list archive)
State Superseded
Headers show
Series PCI: dwc: Fix higher MSI vectors handling | expand

Commit Message

Dmitry Baryshkov June 3, 2022, 7:41 a.m. UTC
On some of Qualcomm platforms each group of 32 MSI vectors is routed to the
separate GIC interrupt. Implement support for such configurations by
parsing "msi0" ... "msiN" interrupts and attaching them to the chained
handler.

Note, that if DT doesn't list an array of MSI interrupts and uses single
"msi" IRQ, the driver will limit the amount of supported MSI vectors
accordingly (to 32).

Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 .../pci/controller/dwc/pcie-designware-host.c | 63 +++++++++++++++++--
 1 file changed, 59 insertions(+), 4 deletions(-)

Comments

Johan Hovold June 6, 2022, 4:27 p.m. UTC | #1
On Fri, Jun 03, 2022 at 10:41:34AM +0300, Dmitry Baryshkov wrote:
> On some of Qualcomm platforms each group of 32 MSI vectors is routed to the
> separate GIC interrupt. Implement support for such configurations by
> parsing "msi0" ... "msiN" interrupts and attaching them to the chained
> handler.
> 
> Note, that if DT doesn't list an array of MSI interrupts and uses single
> "msi" IRQ, the driver will limit the amount of supported MSI vectors
> accordingly (to 32).
> 
> Reviewed-by: Rob Herring <robh@kernel.org>
> Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---
>  .../pci/controller/dwc/pcie-designware-host.c | 63 +++++++++++++++++--
>  1 file changed, 59 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index 85c1160792e1..d1f9e20df903 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -289,6 +289,46 @@ static void dw_pcie_msi_init(struct pcie_port *pp)
>  	dw_pcie_writel_dbi(pci, PCIE_MSI_ADDR_HI, upper_32_bits(msi_target));
>  }
>  
> +static int dw_pcie_parse_split_msi_irq(struct pcie_port *pp)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> +	struct device *dev = pci->dev;
> +	struct platform_device *pdev = to_platform_device(dev);
> +	int irq;
> +	u32 ctrl, max_vectors;
> +
> +	/* Parse as many IRQs as described in the devicetree. */
> +	for (ctrl = 0; ctrl < MAX_MSI_CTRLS; ctrl++) {
> +		char *msi_name = "msiX";
> +
> +		msi_name[3] = '0' + ctrl;

This oopses here as the string constant is read only:

	[   19.787973] Unable to handle kernel write to read-only memory at virtual address ffffaa14f831afd3

Did you not test the series before posting?

You need to define msi_name as:

	char msi_name[] = "msiX";

> +		irq = platform_get_irq_byname_optional(pdev, msi_name);
> +		if (irq == -ENXIO)
> +			break;
> +		if (irq < 0)
> +			return dev_err_probe(dev, irq,
> +					     "Failed to parse MSI IRQ '%s'\n",
> +					     msi_name);
> +
> +		pp->msi_irq[ctrl] = irq;
> +	}

Johan
Dmitry Baryshkov June 8, 2022, 8:58 a.m. UTC | #2
On 06/06/2022 19:27, Johan Hovold wrote:
> On Fri, Jun 03, 2022 at 10:41:34AM +0300, Dmitry Baryshkov wrote:
>> On some of Qualcomm platforms each group of 32 MSI vectors is routed to the
>> separate GIC interrupt. Implement support for such configurations by
>> parsing "msi0" ... "msiN" interrupts and attaching them to the chained
>> handler.
>>
>> Note, that if DT doesn't list an array of MSI interrupts and uses single
>> "msi" IRQ, the driver will limit the amount of supported MSI vectors
>> accordingly (to 32).
>>
>> Reviewed-by: Rob Herring <robh@kernel.org>
>> Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>> ---
>>   .../pci/controller/dwc/pcie-designware-host.c | 63 +++++++++++++++++--
>>   1 file changed, 59 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
>> index 85c1160792e1..d1f9e20df903 100644
>> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
>> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
>> @@ -289,6 +289,46 @@ static void dw_pcie_msi_init(struct pcie_port *pp)
>>   	dw_pcie_writel_dbi(pci, PCIE_MSI_ADDR_HI, upper_32_bits(msi_target));
>>   }
>>   
>> +static int dw_pcie_parse_split_msi_irq(struct pcie_port *pp)
>> +{
>> +	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>> +	struct device *dev = pci->dev;
>> +	struct platform_device *pdev = to_platform_device(dev);
>> +	int irq;
>> +	u32 ctrl, max_vectors;
>> +
>> +	/* Parse as many IRQs as described in the devicetree. */
>> +	for (ctrl = 0; ctrl < MAX_MSI_CTRLS; ctrl++) {
>> +		char *msi_name = "msiX";
>> +
>> +		msi_name[3] = '0' + ctrl;
> 
> This oopses here as the string constant is read only:
> 
> 	[   19.787973] Unable to handle kernel write to read-only memory at virtual address ffffaa14f831afd3
> 
> Did you not test the series before posting?

Interesting enough the posted series works for me. Maybe I have a 
different set of debugging options. But thanks for spotting this. I'll 
post v14.

> 
> You need to define msi_name as:
> 
> 	char msi_name[] = "msiX";
> 
>> +		irq = platform_get_irq_byname_optional(pdev, msi_name);
>> +		if (irq == -ENXIO)
>> +			break;
>> +		if (irq < 0)
>> +			return dev_err_probe(dev, irq,
>> +					     "Failed to parse MSI IRQ '%s'\n",
>> +					     msi_name);
>> +
>> +		pp->msi_irq[ctrl] = irq;
>> +	}
> 
> Johan
diff mbox series

Patch

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 85c1160792e1..d1f9e20df903 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -289,6 +289,46 @@  static void dw_pcie_msi_init(struct pcie_port *pp)
 	dw_pcie_writel_dbi(pci, PCIE_MSI_ADDR_HI, upper_32_bits(msi_target));
 }
 
+static int dw_pcie_parse_split_msi_irq(struct pcie_port *pp)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct device *dev = pci->dev;
+	struct platform_device *pdev = to_platform_device(dev);
+	int irq;
+	u32 ctrl, max_vectors;
+
+	/* Parse as many IRQs as described in the devicetree. */
+	for (ctrl = 0; ctrl < MAX_MSI_CTRLS; ctrl++) {
+		char *msi_name = "msiX";
+
+		msi_name[3] = '0' + ctrl;
+		irq = platform_get_irq_byname_optional(pdev, msi_name);
+		if (irq == -ENXIO)
+			break;
+		if (irq < 0)
+			return dev_err_probe(dev, irq,
+					     "Failed to parse MSI IRQ '%s'\n",
+					     msi_name);
+
+		pp->msi_irq[ctrl] = irq;
+	}
+
+	/* If there were no "msiN" IRQs at all, fallback to the standard "msi" IRQ. */
+	if (ctrl == 0)
+		return -ENXIO;
+
+	max_vectors = ctrl * MAX_MSI_IRQS_PER_CTRL;
+	if (pp->num_vectors > max_vectors) {
+		dev_warn(dev, "Exceeding number of MSI vectors, limiting to %u\n",
+			 max_vectors);
+		pp->num_vectors = max_vectors;
+	}
+	if (!pp->num_vectors)
+		pp->num_vectors = max_vectors;
+
+	return 0;
+}
+
 static int dw_pcie_msi_host_init(struct pcie_port *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
@@ -297,21 +337,32 @@  static int dw_pcie_msi_host_init(struct pcie_port *pp)
 	int ret;
 	u32 ctrl, num_ctrls;
 
-	num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
-	for (ctrl = 0; ctrl < num_ctrls; ctrl++)
+	for (ctrl = 0; ctrl < MAX_MSI_CTRLS; ctrl++)
 		pp->irq_mask[ctrl] = ~0;
 
+	if (!pp->msi_irq[0]) {
+		ret = dw_pcie_parse_split_msi_irq(pp);
+		if (ret < 0 && ret != -ENXIO)
+			return ret;
+	}
+
+	if (!pp->num_vectors)
+		pp->num_vectors = MSI_DEF_NUM_VECTORS;
+	num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
+
 	if (!pp->msi_irq[0]) {
 		int irq = platform_get_irq_byname_optional(pdev, "msi");
 
 		if (irq < 0) {
 			irq = platform_get_irq(pdev, 0);
 			if (irq < 0)
-				return irq;
+				return dev_err_probe(dev, irq, "Failed to parse MSI irq\n");
 		}
 		pp->msi_irq[0] = irq;
 	}
 
+	dev_dbg(dev, "Using %d MSI vectors\n", pp->num_vectors);
+
 	pp->msi_irq_chip = &dw_pci_msi_bottom_irq_chip;
 
 	ret = dw_pcie_allocate_domains(pp);
@@ -409,7 +460,11 @@  int dw_pcie_host_init(struct pcie_port *pp)
 				     of_property_read_bool(np, "msi-parent") ||
 				     of_property_read_bool(np, "msi-map"));
 
-		if (!pp->num_vectors) {
+		/*
+		 * For the has_msi_ctrl case the default assignment is handled
+		 * in the dw_pcie_msi_host_init().
+		 */
+		if (!pp->has_msi_ctrl && !pp->num_vectors) {
 			pp->num_vectors = MSI_DEF_NUM_VECTORS;
 		} else if (pp->num_vectors > MAX_MSI_IRQS) {
 			dev_err(dev, "Invalid number of vectors\n");