[v2,3/4] PCI: brcmstb: Wait for Raspberry Pi's firmware when present
diff mbox series

Message ID 20200219123933.2792-4-nsaenzjulienne@suse.de
State Superseded
Headers show
Series
  • Raspberry Pi 4 VL805 firmware load support
Related show

Commit Message

Nicolas Saenz Julienne Feb. 19, 2020, 12:39 p.m. UTC
xHCI's PCI fixup, run at the end of pcie-brcmstb's probe, depends on
RPi4's VideoCore firmware interface to be up and running. It's possible
for both initializations to race, so make sure it's available prior
starting.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---
 drivers/pci/controller/pcie-brcmstb.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

Comments

Florian Fainelli Feb. 19, 2020, 7:21 p.m. UTC | #1
On 2/19/20 4:39 AM, Nicolas Saenz Julienne wrote:
> xHCI's PCI fixup, run at the end of pcie-brcmstb's probe, depends on
> RPi4's VideoCore firmware interface to be up and running. It's possible
> for both initializations to race, so make sure it's available prior
> starting.
> 
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>

It does not look like there is something making sure that
CONFIG_RASPBERRYPI_FIRMWARE is being selected or depended on, should we
have a "default XHCI_PCI" added to drivers/firmware/Kconfig?
Nicolas Saenz Julienne Feb. 20, 2020, 6:14 p.m. UTC | #2
On Wed, 2020-02-19 at 11:21 -0800, Florian Fainelli wrote:
> On 2/19/20 4:39 AM, Nicolas Saenz Julienne wrote:
> > xHCI's PCI fixup, run at the end of pcie-brcmstb's probe, depends on
> > RPi4's VideoCore firmware interface to be up and running. It's possible
> > for both initializations to race, so make sure it's available prior
> > starting.
> > 
> > Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
> 
> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
> 
> It does not look like there is something making sure that
> CONFIG_RASPBERRYPI_FIRMWARE is being selected or depended on, should we
> have a "default XHCI_PCI" added to drivers/firmware/Kconfig?

I think having that would enable the firmware interface for all XHCI_PCI users,
which isn't ideal. The firmware call has stubs for the case the firmware
interace isn't compiled, so no problem there. Ultimately we want to enable
CONFIG_RASPBERRYPI_FIRMWARE only when the built image targets the RPi4
(reglardless of being arm64/arm32). But I don't think that's feasible.

Regards,
Nicolas
Florian Fainelli Feb. 20, 2020, 6:27 p.m. UTC | #3
On 2/20/2020 10:14 AM, Nicolas Saenz Julienne wrote:
> On Wed, 2020-02-19 at 11:21 -0800, Florian Fainelli wrote:
>> On 2/19/20 4:39 AM, Nicolas Saenz Julienne wrote:
>>> xHCI's PCI fixup, run at the end of pcie-brcmstb's probe, depends on
>>> RPi4's VideoCore firmware interface to be up and running. It's possible
>>> for both initializations to race, so make sure it's available prior
>>> starting.
>>>
>>> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
>>
>> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
>>
>> It does not look like there is something making sure that
>> CONFIG_RASPBERRYPI_FIRMWARE is being selected or depended on, should we
>> have a "default XHCI_PCI" added to drivers/firmware/Kconfig?
> 
> I think having that would enable the firmware interface for all XHCI_PCI users,
> which isn't ideal. The firmware call has stubs for the case the firmware
> interace isn't compiled, so no problem there. Ultimately we want to enable
> CONFIG_RASPBERRYPI_FIRMWARE only when the built image targets the RPi4
> (reglardless of being arm64/arm32). But I don't think that's feasible.

It would enable the driver, which is only functional if the matching
Device Tree node is present, that seems like a reasonable price to pay
for a multiplatform kernel. After all, this is a functional dependency
for the Pi4.

Patch
diff mbox series

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index d20aabc26273..9600052f768c 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -28,6 +28,8 @@ 
 #include <linux/string.h>
 #include <linux/types.h>
 
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
 #include "../pci.h"
 
 /* BRCM_PCIE_CAP_REGS - Offset for the mandatory capability config regs */
@@ -917,11 +919,24 @@  static int brcm_pcie_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node, *msi_np;
 	struct pci_host_bridge *bridge;
+	struct device_node *fw_np;
 	struct brcm_pcie *pcie;
 	struct pci_bus *child;
 	struct resource *res;
 	int ret;
 
+	/*
+	 * We have to wait for the Raspberry Pi's firmware interface to be up
+	 * as some PCI fixups depend on it.
+	 */
+	fw_np = of_find_compatible_node(NULL, NULL,
+					"raspberrypi,bcm2835-firmware");
+	if (fw_np && !rpi_firmware_get(fw_np)) {
+		of_node_put(fw_np);
+		return -EPROBE_DEFER;
+	}
+	of_node_put(fw_np);
+
 	bridge = devm_pci_alloc_host_bridge(&pdev->dev, sizeof(*pcie));
 	if (!bridge)
 		return -ENOMEM;