linux-kernel - Re: [PATCH v2 1/2] arm: rpi: Add function to trigger VL805's firmware load

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Message-ID: <0161a6a5254871ce@bloch.sibelius.xs4all.nl>
Date:   Thu, 30 Apr 2020 15:31:58 +0200 (CEST)
From:   Mark Kettenis <mark.kettenis@...all.nl>
To:     Nicolas Saenz Julienne <nsaenzjulienne@...e.de>
CC:     mbrugger@...e.com, u-boot@...ts.denx.de, bmeng.cn@...il.com,
        marex@...x.de, linux-kernel@...r.kernel.org, sjg@...omium.org,
        m.szyprowski@...sung.com, s.nawrocki@...sung.com,
        nsaenzjulienne@...e.de
Subject: Re: [PATCH v2 1/2] arm: rpi: Add function to trigger VL805's firmware load

> From: Nicolas Saenz Julienne <nsaenzjulienne@...e.de>
> Date: Thu, 30 Apr 2020 15:04:32 +0200
> 
> On the Raspberry Pi 4, after a PCI reset, VL805's (a xHCI chip) firmware
> may either be loaded directly from an EEPROM or, if not present, by the
> SoC's VideoCore (the SoC's co-processor). Introduce the function that
> informs VideoCore that VL805 may need its firmware loaded.
> 
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@...e.de>
> 
> ---
> Changes since v1:
>  - Rename function so it's not mistaken with regular firmware loading
> 
>  arch/arm/mach-bcm283x/include/mach/mbox.h | 13 +++++++
>  arch/arm/mach-bcm283x/include/mach/msg.h  |  7 ++++
>  arch/arm/mach-bcm283x/msg.c               | 43 +++++++++++++++++++++++
>  3 files changed, 63 insertions(+)
> 
> diff --git a/arch/arm/mach-bcm283x/include/mach/mbox.h b/arch/arm/mach-bcm283x/include/mach/mbox.h
> index 60e226ce1d..2ae2d3d97c 100644
> --- a/arch/arm/mach-bcm283x/include/mach/mbox.h
> +++ b/arch/arm/mach-bcm283x/include/mach/mbox.h
> @@ -491,6 +491,19 @@ struct bcm2835_mbox_tag_set_palette {
>  	} body;
>  };
>  
> +#define BCM2835_MBOX_TAG_NOTIFY_XHCI_RESET          0x00030058
> +
> +struct bcm2835_mbox_tag_pci_dev_addr {
> +	struct bcm2835_mbox_tag_hdr tag_hdr;
> +	union {
> +		struct {
> +			u32 dev_addr;
> +		} req;
> +		struct {
> +		} resp;
> +	} body;
> +};
> +
>  /*
>   * Pass a raw u32 message to the VC, and receive a raw u32 back.
>   *
> diff --git a/arch/arm/mach-bcm283x/include/mach/msg.h b/arch/arm/mach-bcm283x/include/mach/msg.h
> index 4afb08631b..e45c1bf010 100644
> --- a/arch/arm/mach-bcm283x/include/mach/msg.h
> +++ b/arch/arm/mach-bcm283x/include/mach/msg.h
> @@ -48,4 +48,11 @@ int bcm2835_set_video_params(int *widthp, int *heightp, int depth_bpp,
>  			     int pixel_order, int alpha_mode, ulong *fb_basep,
>  			     ulong *fb_sizep, int *pitchp);
>  
> +/**
> + * bcm2711_load_vl805_firmware() - get vl805's firmware loaded
> + *
> + * @return 0 if OK, -EIO on error
> + */
> +int bcm2711_notify_vl805_reset(void);

Now the comment and function prototype don't agree :(.

> +
>  #endif
> diff --git a/arch/arm/mach-bcm283x/msg.c b/arch/arm/mach-bcm283x/msg.c
> index 94b75283f8..a338190d33 100644
> --- a/arch/arm/mach-bcm283x/msg.c
> +++ b/arch/arm/mach-bcm283x/msg.c
> @@ -40,6 +40,12 @@ struct msg_setup {
>  	u32 end_tag;
>  };
>  
> +struct msg_notify_vl805_reset {
> +	struct bcm2835_mbox_hdr hdr;
> +	struct bcm2835_mbox_tag_pci_dev_addr dev_addr;
> +	u32 end_tag;
> +};
> +
>  int bcm2835_power_on_module(u32 module)
>  {
>  	ALLOC_CACHE_ALIGN_BUFFER(struct msg_set_power_state, msg_pwr, 1);
> @@ -151,3 +157,40 @@ int bcm2835_set_video_params(int *widthp, int *heightp, int depth_bpp,
>  
>  	return 0;
>  }
> +
> +/*
> + * On the Raspberry Pi 4, after a PCI reset, VL805's (the xHCI chip) firmware
> + * may either be loaded directly from an EEPROM or, if not present, by the
> + * SoC's VideoCore. This informs VideoCore that VL805 needs its firmware
> + * loaded.
> + */
> +int bcm2711_notify_vl805_reset(void)
> +{
> +	ALLOC_CACHE_ALIGN_BUFFER(struct msg_notify_vl805_reset,
> +				 msg_notify_vl805_reset, 1);
> +	int ret;
> +
> +	BCM2835_MBOX_INIT_HDR(msg_notify_vl805_reset);
> +	BCM2835_MBOX_INIT_TAG(&msg_notify_vl805_reset->dev_addr,
> +			      NOTIFY_XHCI_RESET);
> +
> +	/*
> +	 * The pci device address is expected like this:
> +	 *
> +	 *   PCI_BUS << 20 | PCI_SLOT << 15 | PCI_FUNC << 12
> +	 *
> +	 * But since RPi4's PCIe setup is hardwired, we know the address in
> +	 * advance.
> +	 */
> +	msg_notify_vl805_reset->dev_addr.body.req.dev_addr = 0x100000;
> +
> +	ret = bcm2835_mbox_call_prop(BCM2835_MBOX_PROP_CHAN,
> +				     &msg_notify_vl805_reset->hdr);
> +	if (ret) {
> +		printf("bcm2711: Faild to load vl805's firmware, %d\n", ret);
> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
> -- 
> 2.26.2
> 
>