[v7,2/4] firmware: raspberrypi: Introduce vl805 init routine
diff mbox series

Message ID 20200429164734.21506-3-nsaenzjulienne@suse.de
State Superseded
Headers show
Series
  • USB: pci-quirks: Add Raspberry Pi 4 quirk
Related show

Commit Message

Nicolas Saenz Julienne April 29, 2020, 4:47 p.m. UTC
The Raspberry Pi 4 gets its USB functionality from VL805, a PCIe chip
that implements xHCI. After a PCI reset, VL805's firmware may either be
loaded directly from an EEPROM or, if not present, by the SoC's
co-processor, VideoCore. RPi4's VideoCore OS contains both the non public
firmware load logic and the VL805 firmware blob. The function this patch
introduces triggers the aforementioned process.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>

---

Change since v6:
- Add test to avoid loading the firmware when not needed
- Since we have it around, print VL805's firmware version, it'll make
debugging easier in the future
- Correct typos
- Add a clearer view of HW topology in patch description

Changes since v4:
- Inline function definition when RASPBERRYPI_FIRMWARE is not defined

Changes since v1:
- Move include into .c file and add forward declaration to .h

 drivers/firmware/raspberrypi.c             | 52 ++++++++++++++++++++++
 include/soc/bcm2835/raspberrypi-firmware.h |  7 +++
 2 files changed, 59 insertions(+)

Comments

Stefan Wahren May 2, 2020, 9:05 a.m. UTC | #1
Hi Nicolas,

Am 29.04.20 um 18:47 schrieb Nicolas Saenz Julienne:
> The Raspberry Pi 4 gets its USB functionality from VL805, a PCIe chip
> that implements xHCI. After a PCI reset, VL805's firmware may either be
> loaded directly from an EEPROM or, if not present, by the SoC's
> co-processor, VideoCore. RPi4's VideoCore OS contains both the non public
> firmware load logic and the VL805 firmware blob. The function this patch
> introduces triggers the aforementioned process.
>
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
>
> ---
>
> Change since v6:
> - Add test to avoid loading the firmware when not needed
> - Since we have it around, print VL805's firmware version, it'll make
> debugging easier in the future
> - Correct typos
> - Add a clearer view of HW topology in patch description
>
> Changes since v4:
> - Inline function definition when RASPBERRYPI_FIRMWARE is not defined
>
> Changes since v1:
> - Move include into .c file and add forward declaration to .h
>
>  drivers/firmware/raspberrypi.c             | 52 ++++++++++++++++++++++
>  include/soc/bcm2835/raspberrypi-firmware.h |  7 +++
>  2 files changed, 59 insertions(+)
>
> diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c
> index da26a584dca0..230c05e53403 100644
> --- a/drivers/firmware/raspberrypi.c
> +++ b/drivers/firmware/raspberrypi.c
> @@ -12,6 +12,8 @@
>  #include <linux/of_platform.h>
>  #include <linux/platform_device.h>
>  #include <linux/slab.h>
> +#include <linux/pci.h>
> +#include <linux/delay.h>
>  #include <soc/bcm2835/raspberrypi-firmware.h>
>
>  #define MBOX_MSG(chan, data28)		(((data28) & ~0xf) | ((chan) & 0xf))
> @@ -19,6 +21,8 @@
>  #define MBOX_DATA28(msg)		((msg) & ~0xf)
>  #define MBOX_CHAN_PROPERTY		8
>
> +#define VL805_PCI_CONFIG_VERSION_OFFSET		0x50
> +
>  static struct platform_device *rpi_hwmon;
>  static struct platform_device *rpi_clk;
>
> @@ -286,6 +290,54 @@ struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
>  }
>  EXPORT_SYMBOL_GPL(rpi_firmware_get);
>
> +/*
> + * The Raspberry Pi 4 gets its USB functionality from VL805, a PCIe chip that
> + * implements xHCI. After a PCI reset, VL805's firmware may either be loaded
> + * directly from an EEPROM or, if not present, by the SoC's co-processor,
> + * VideoCore. RPi4's VideoCore OS contains both the non public firmware load
> + * logic and the VL805 firmware blob. This function triggers the aforementioned
> + * process.
> + */
> +int rpi_firmware_init_vl805(struct pci_dev *pdev)
> +{
> +	struct device_node *fw_np;
> +	struct rpi_firmware *fw;
> +	u32 dev_addr, version;
> +	int ret = 0;
> +
> +	fw_np = of_find_compatible_node(NULL, NULL,
> +					"raspberrypi,bcm2835-firmware");
> +	if (!fw_np)
> +		return 0;
> +
> +	fw = rpi_firmware_get(fw_np);
> +	of_node_put(fw_np);
> +	if (!fw)
> +		return -ENODEV;
> +
> +	/* Make sure we don't trigger a firmware load unnecesarely *
s/unnecesarely/unnecessarily/
> +	pci_read_config_dword(pdev, VL805_PCI_CONFIG_VERSION_OFFSET, &version);
pci_read_config_dword() can fail, we might want to store the return value?
> +	if (version)
> +		goto exit;
> +
> +	dev_addr = pdev->bus->number << 20 | PCI_SLOT(pdev->devfn) << 15 |
> +		   PCI_FUNC(pdev->devfn) << 12;
> +
> +	ret = rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_XHCI_RESET,
> +				    &dev_addr, sizeof(dev_addr));
> +	/* Wait for vl805 to startup */
> +	udelay(200);

I know, it makes it harder to read but do we really want to wait
unnecessarily if rpi_firmware_property failed?

Btw i assume we are in non-atomic context, so maybe it's worth to use
usleep_range() here?

> +
> +exit:
> +	if (!version)
> +		pci_read_config_dword(pdev, VL805_PCI_CONFIG_VERSION_OFFSET,
> +				      &version);
> +	pci_info(pdev, "VL805 firmware version %08x\n", version);

In case pci_read_config_dword() fails the return code would be more helpful.

Best regards

> +	return ret;
> +
> +}
> +EXPORT_SYMBOL_GPL(rpi_firmware_init_vl805);
> +
>  static const struct of_device_id rpi_firmware_of_match[] = {
>  	{ .compatible = "raspberrypi,bcm2835-firmware", },
>  	{},
> diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h
> index cc9cdbc66403..3025aca3c358 100644
> --- a/include/soc/bcm2835/raspberrypi-firmware.h
> +++ b/include/soc/bcm2835/raspberrypi-firmware.h
> @@ -10,6 +10,7 @@
>  #include <linux/of_device.h>
>
>  struct rpi_firmware;
> +struct pci_dev;
>
>  enum rpi_firmware_property_status {
>  	RPI_FIRMWARE_STATUS_REQUEST = 0,
> @@ -141,6 +142,7 @@ int rpi_firmware_property(struct rpi_firmware *fw,
>  int rpi_firmware_property_list(struct rpi_firmware *fw,
>  			       void *data, size_t tag_size);
>  struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node);
> +int rpi_firmware_init_vl805(struct pci_dev *pdev);
>  #else
>  static inline int rpi_firmware_property(struct rpi_firmware *fw, u32 tag,
>  					void *data, size_t len)
> @@ -158,6 +160,11 @@ static inline struct rpi_firmware *rpi_firmware_get(struct device_node *firmware
>  {
>  	return NULL;
>  }
> +
> +static inline int rpi_firmware_init_vl805(struct pci_dev *pdev)
> +{
> +	return 0;
> +}
>  #endif
>
>  #endif /* __SOC_RASPBERRY_FIRMWARE_H__ */
Nicolas Saenz Julienne May 4, 2020, 8:59 a.m. UTC | #2
Hi Stefan, thanks for the review!

On Sat, 2020-05-02 at 11:05 +0200, Stefan Wahren wrote:
> > +	/* Make sure we don't trigger a firmware load unnecesarely *
> s/unnecesarely/unnecessarily/

Noted

> > +	pci_read_config_dword(pdev, VL805_PCI_CONFIG_VERSION_OFFSET, &version);
> pci_read_config_dword() can fail, we might want to store the return value?

I planned on doing that, but realised that the vast majority of
pci_read_config_*() users pass on checking for errors.

Bjorn, any rule of thumb on when to check for errors here?

> > +	if (version)
> > +		goto exit;
> > +
> > +	dev_addr = pdev->bus->number << 20 | PCI_SLOT(pdev->devfn) << 15 |
> > +		   PCI_FUNC(pdev->devfn) << 12;
> > +
> > +	ret = rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_XHCI_RESET,
> > +				    &dev_addr, sizeof(dev_addr));
> > +	/* Wait for vl805 to startup */
> > +	udelay(200);
> 
> I know, it makes it harder to read but do we really want to wait
> unnecessarily if rpi_firmware_property failed?

Yes, I figured that it wouldn't hurt much at that faulty state, and you'll be
waiting some extra 5s further down the line in quirk_usb_handoff_xhci().

But if you feel it's more correct I'll be happy to change it.

> Btw i assume we are in non-atomic context, so maybe it's worth to use
> usleep_range() here?

Of course, I'll fix that.

Regards,
Nicolas
Stefan Wahren May 4, 2020, 7:06 p.m. UTC | #3
Hi Nicolas,

Am 04.05.20 um 10:59 schrieb Nicolas Saenz Julienne:
> Hi Stefan, thanks for the review!
>
> On Sat, 2020-05-02 at 11:05 +0200, Stefan Wahren wrote:
>>> +	if (version)
>>> +		goto exit;
>>> +
>>> +	dev_addr = pdev->bus->number << 20 | PCI_SLOT(pdev->devfn) << 15 |
>>> +		   PCI_FUNC(pdev->devfn) << 12;
>>> +
>>> +	ret = rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_XHCI_RESET,
>>> +				    &dev_addr, sizeof(dev_addr));
>>> +	/* Wait for vl805 to startup */
>>> +	udelay(200);
>> I know, it makes it harder to read but do we really want to wait
>> unnecessarily if rpi_firmware_property failed?
> Yes, I figured that it wouldn't hurt much at that faulty state, and you'll be
> waiting some extra 5s further down the line in quirk_usb_handoff_xhci().
>
> But if you feel it's more correct I'll be happy to change it.

no, i don't insist on that.

Best regards
Stefan
Bjorn Helgaas May 4, 2020, 10:52 p.m. UTC | #4
On Mon, May 04, 2020 at 10:59:29AM +0200, Nicolas Saenz Julienne wrote:
> On Sat, 2020-05-02 at 11:05 +0200, Stefan Wahren wrote:
> > > +	pci_read_config_dword(pdev, VL805_PCI_CONFIG_VERSION_OFFSET, &version);
> > pci_read_config_dword() can fail, we might want to store the return value?
> 
> I planned on doing that, but realised that the vast majority of
> pci_read_config_*() users pass on checking for errors.
> 
> Bjorn, any rule of thumb on when to check for errors here?

Not really.  It *can* fail, for sure.  If it does fail, you normally
get ~0 data, which means you would skip the firmware load, do another
config read (which probably also returns ~0) and print firmware
version ffffffff, and the device probably won't work.

But checking doesn't get you much other than a better error message.

Personally I probably wouldn't bother because it clutters the code so
much for so little benefit.

Bjorn

Patch
diff mbox series

diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c
index da26a584dca0..230c05e53403 100644
--- a/drivers/firmware/raspberrypi.c
+++ b/drivers/firmware/raspberrypi.c
@@ -12,6 +12,8 @@ 
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
+#include <linux/pci.h>
+#include <linux/delay.h>
 #include <soc/bcm2835/raspberrypi-firmware.h>
 
 #define MBOX_MSG(chan, data28)		(((data28) & ~0xf) | ((chan) & 0xf))
@@ -19,6 +21,8 @@ 
 #define MBOX_DATA28(msg)		((msg) & ~0xf)
 #define MBOX_CHAN_PROPERTY		8
 
+#define VL805_PCI_CONFIG_VERSION_OFFSET		0x50
+
 static struct platform_device *rpi_hwmon;
 static struct platform_device *rpi_clk;
 
@@ -286,6 +290,54 @@  struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
 }
 EXPORT_SYMBOL_GPL(rpi_firmware_get);
 
+/*
+ * The Raspberry Pi 4 gets its USB functionality from VL805, a PCIe chip that
+ * implements xHCI. After a PCI reset, VL805's firmware may either be loaded
+ * directly from an EEPROM or, if not present, by the SoC's co-processor,
+ * VideoCore. RPi4's VideoCore OS contains both the non public firmware load
+ * logic and the VL805 firmware blob. This function triggers the aforementioned
+ * process.
+ */
+int rpi_firmware_init_vl805(struct pci_dev *pdev)
+{
+	struct device_node *fw_np;
+	struct rpi_firmware *fw;
+	u32 dev_addr, version;
+	int ret = 0;
+
+	fw_np = of_find_compatible_node(NULL, NULL,
+					"raspberrypi,bcm2835-firmware");
+	if (!fw_np)
+		return 0;
+
+	fw = rpi_firmware_get(fw_np);
+	of_node_put(fw_np);
+	if (!fw)
+		return -ENODEV;
+
+	/* Make sure we don't trigger a firmware load unnecesarely */
+	pci_read_config_dword(pdev, VL805_PCI_CONFIG_VERSION_OFFSET, &version);
+	if (version)
+		goto exit;
+
+	dev_addr = pdev->bus->number << 20 | PCI_SLOT(pdev->devfn) << 15 |
+		   PCI_FUNC(pdev->devfn) << 12;
+
+	ret = rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_XHCI_RESET,
+				    &dev_addr, sizeof(dev_addr));
+	/* Wait for vl805 to startup */
+	udelay(200);
+
+exit:
+	if (!version)
+		pci_read_config_dword(pdev, VL805_PCI_CONFIG_VERSION_OFFSET,
+				      &version);
+	pci_info(pdev, "VL805 firmware version %08x\n", version);
+	return ret;
+
+}
+EXPORT_SYMBOL_GPL(rpi_firmware_init_vl805);
+
 static const struct of_device_id rpi_firmware_of_match[] = {
 	{ .compatible = "raspberrypi,bcm2835-firmware", },
 	{},
diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h
index cc9cdbc66403..3025aca3c358 100644
--- a/include/soc/bcm2835/raspberrypi-firmware.h
+++ b/include/soc/bcm2835/raspberrypi-firmware.h
@@ -10,6 +10,7 @@ 
 #include <linux/of_device.h>
 
 struct rpi_firmware;
+struct pci_dev;
 
 enum rpi_firmware_property_status {
 	RPI_FIRMWARE_STATUS_REQUEST = 0,
@@ -141,6 +142,7 @@  int rpi_firmware_property(struct rpi_firmware *fw,
 int rpi_firmware_property_list(struct rpi_firmware *fw,
 			       void *data, size_t tag_size);
 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node);
+int rpi_firmware_init_vl805(struct pci_dev *pdev);
 #else
 static inline int rpi_firmware_property(struct rpi_firmware *fw, u32 tag,
 					void *data, size_t len)
@@ -158,6 +160,11 @@  static inline struct rpi_firmware *rpi_firmware_get(struct device_node *firmware
 {
 	return NULL;
 }
+
+static inline int rpi_firmware_init_vl805(struct pci_dev *pdev)
+{
+	return 0;
+}
 #endif
 
 #endif /* __SOC_RASPBERRY_FIRMWARE_H__ */