Re: [PATCH v5 08/10] misc: rp1: RaspberryPi RP1 misc driver

Rob Herring
2024-12-10T22:48:40Z

On Mon, Dec 02, 2024 at 12:19:32PM +0100, Andrea della Porta wrote:
> The RaspberryPi RP1 is a PCI multi function device containing
> peripherals ranging from Ethernet to USB controller, I2C, SPI
> and others.
>
> Implement a bare minimum driver to operate the RP1, leveraging
> actual OF based driver implementations for the on-board peripherals
> by loading a devicetree overlay during driver probe.
>
> The peripherals are accessed by mapping MMIO registers starting
> from PCI BAR1 region.
>
> With the overlay approach we can achieve more generic and agnostic
> approach to managing this chipset, being that it is a PCI endpoint
> and could possibly be reused in other hw implementations. The
> presented approach is also used by Bootlin's Microchip LAN966x
> patchset (see link) as well, for a similar chipset.
>
> Since the gpio line names should be provided by the user, there
> is an interface through configfs that allows the userspace to
> load a DT overlay that will provide gpio-line-names property.
> The interface can be invoked like this:
>
> cat rpi-rp1-gpios-5-b.dtbo > /sys/kernel/config/rp1-cfg/gpio_set_names

Where's the configfs support? This looks like a stale comment.

If this is the general purpose configfs interface for overlays, that's
likely never going upstream. If you want this support, then you should
load your overlay with the firmware loader instead of building it into
the kernel. You can of course add that later.

> and is designed to be similar to what users are already used to
> from distro with downstream kernel.
>
> For reasons why this driver is contained in drivers/misc, please
> check the links.
>
> This driver is heavily based on downstream code from RaspberryPi
> Foundation, and the original author is Phil Elwell.
>
> Link: https://datasheets.raspberrypi.com/rp1/rp1-peripherals.pdf
> Link: https://lore.kernel.org/all/20240612140208.GC1504919@google.com/
> Link: https://lore.kernel.org/all/83f7fa09-d0e6-4f36-a27d-cee08979be2a@app.fastmail.com/
> Link: https://lore.kernel.org/all/2024081356-mutable-everyday-6f9d@gregkh/
> Link: https://lore.kernel.org/all/20240808154658.247873-1-herve.codina@bootlin.com/
>
> Signed-off-by: Andrea della Porta <andrea.porta@suse.com>
> ---
> MAINTAINERS | 1 +
> drivers/misc/Kconfig | 1 +
> drivers/misc/Makefile | 1 +
> drivers/misc/rp1/Kconfig | 21 ++
> drivers/misc/rp1/Makefile | 3 +
> drivers/misc/rp1/rp1-pci.dtso | 8 +
> drivers/misc/rp1/rp1_pci.c | 366 ++++++++++++++++++++++++++++++++++
> drivers/misc/rp1/rp1_pci.h | 14 ++
> drivers/pci/quirks.c | 1 +
> include/linux/pci_ids.h | 3 +
> 10 files changed, 419 insertions(+)
> create mode 100644 drivers/misc/rp1/Kconfig
> create mode 100644 drivers/misc/rp1/Makefile
> create mode 100644 drivers/misc/rp1/rp1-pci.dtso
> create mode 100644 drivers/misc/rp1/rp1_pci.c
> create mode 100644 drivers/misc/rp1/rp1_pci.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index fbdd8594aa7e..d67ba6d10aa8 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -19583,6 +19583,7 @@ F: Documentation/devicetree/bindings/misc/pci1de4,1.yaml
> F: Documentation/devicetree/bindings/pci/pci-ep-bus.yaml
> F: Documentation/devicetree/bindings/pinctrl/raspberrypi,rp1-gpio.yaml
> F: drivers/clk/clk-rp1.c
> +F: drivers/misc/rp1/
> F: drivers/pinctrl/pinctrl-rp1.c
> F: include/dt-bindings/clock/rp1.h
> F: include/dt-bindings/misc/rp1.h
> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index 09cbe3f0ab1e..ffa4d8315c35 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -651,4 +651,5 @@ source "drivers/misc/uacce/Kconfig"
> source "drivers/misc/pvpanic/Kconfig"
> source "drivers/misc/mchp_pci1xxxx/Kconfig"
> source "drivers/misc/keba/Kconfig"
> +source "drivers/misc/rp1/Kconfig"
> endmenu
> diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
> index 40bf953185c7..3b6b07a23aac 100644
> --- a/drivers/misc/Makefile
> +++ b/drivers/misc/Makefile
> @@ -74,3 +74,4 @@ lan966x-pci-objs := lan966x_pci.o
> lan966x-pci-objs += lan966x_pci.dtbo.o
> obj-$(CONFIG_MCHP_LAN966X_PCI) += lan966x-pci.o
> obj-y += keba/
> +obj-$(CONFIG_MISC_RP1) += rp1/
> diff --git a/drivers/misc/rp1/Kconfig b/drivers/misc/rp1/Kconfig
> new file mode 100644
> index 000000000000..15c443e13389
> --- /dev/null
> +++ b/drivers/misc/rp1/Kconfig
> @@ -0,0 +1,21 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +#
> +# RaspberryPi RP1 misc device
> +#
> +
> +config MISC_RP1
> + tristate "RaspberryPi RP1 PCIe support"
> + depends on OF_IRQ && PCI_MSI && PCI_QUIRKS
> + select OF_OVERLAY
> + select PCI_DYNAMIC_OF_NODES
> + help
> + Support the RP1 peripheral chip found on Raspberry Pi 5 board.
> +
> + This device supports several sub-devices including e.g. Ethernet
> + controller, USB controller, I2C, SPI and UART.
> +
> + The driver is responsible for enabling the DT node once the PCIe
> + endpoint has been configured, and handling interrupts.
> +
> + This driver uses an overlay to load other drivers to support for
> + RP1 internal sub-devices.
> diff --git a/drivers/misc/rp1/Makefile b/drivers/misc/rp1/Makefile
> new file mode 100644
> index 000000000000..508b4cb05627
> --- /dev/null
> +++ b/drivers/misc/rp1/Makefile
> @@ -0,0 +1,3 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +obj-$(CONFIG_MISC_RP1) += rp1-pci.o
> +rp1-pci-objs := rp1_pci.o rp1-pci.dtbo.o
> diff --git a/drivers/misc/rp1/rp1-pci.dtso b/drivers/misc/rp1/rp1-pci.dtso
> new file mode 100644
> index 000000000000..0bf2f4bb18e6
> --- /dev/null
> +++ b/drivers/misc/rp1/rp1-pci.dtso
> @@ -0,0 +1,8 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR MIT)
> +
> +/* the dts overlay is included from the dts directory so
> + * it can be possible to check it with CHECK_DTBS while
> + * also compile it from the driver source directory.

I haven't tried, but I think if you set CHECK_DTBS=y, then this file
will get checked. Applying it to the base DT will not though.

> + */
> +
> +#include "arm64/broadcom/rp1.dtso"
> diff --git a/drivers/misc/rp1/rp1_pci.c b/drivers/misc/rp1/rp1_pci.c
> new file mode 100644
> index 000000000000..0dd345341c6f
> --- /dev/null
> +++ b/drivers/misc/rp1/rp1_pci.c
> @@ -0,0 +1,366 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2018-24 Raspberry Pi Ltd.
> + * All rights reserved.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/irqchip/chained_irq.h>
> +#include <linux/irqdomain.h>
> +#include <linux/module.h>
> +#include <linux/msi.h>
> +#include <linux/of_platform.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +
> +#include "rp1_pci.h"
> +
> +#define RP1_DRIVER_NAME "rp1"
> +
> +#define RP1_HW_IRQ_MASK GENMASK(5, 0)
> +
> +#define REG_SET 0x800
> +#define REG_CLR 0xc00
> +
> +/* MSI-X CFG registers start at 0x8 */
> +#define MSIX_CFG(x) (0x8 + (4 * (x)))
> +
> +#define MSIX_CFG_IACK_EN BIT(3)
> +#define MSIX_CFG_IACK BIT(2)
> +#define MSIX_CFG_ENABLE BIT(0)
> +
> +/* Address map */
> +#define RP1_PCIE_APBS_BASE 0x108000
> +
> +/* Interrupts */
> +#define RP1_INT_IO_BANK0 0
> +#define RP1_INT_IO_BANK1 1
> +#define RP1_INT_IO_BANK2 2
> +#define RP1_INT_AUDIO_IN 3
> +#define RP1_INT_AUDIO_OUT 4
> +#define RP1_INT_PWM0 5
> +#define RP1_INT_ETH 6
> +#define RP1_INT_I2C0 7
> +#define RP1_INT_I2C1 8
> +#define RP1_INT_I2C2 9
> +#define RP1_INT_I2C3 10
> +#define RP1_INT_I2C4 11
> +#define RP1_INT_I2C5 12
> +#define RP1_INT_I2C6 13
> +#define RP1_INT_I2S0 14
> +#define RP1_INT_I2S1 15
> +#define RP1_INT_I2S2 16
> +#define RP1_INT_SDIO0 17
> +#define RP1_INT_SDIO1 18
> +#define RP1_INT_SPI0 19
> +#define RP1_INT_SPI1 20
> +#define RP1_INT_SPI2 21
> +#define RP1_INT_SPI3 22
> +#define RP1_INT_SPI4 23
> +#define RP1_INT_SPI5 24
> +#define RP1_INT_UART0 25
> +#define RP1_INT_TIMER_0 26
> +#define RP1_INT_TIMER_1 27
> +#define RP1_INT_TIMER_2 28
> +#define RP1_INT_TIMER_3 29
> +#define RP1_INT_USBHOST0 30
> +#define RP1_INT_USBHOST0_0 31
> +#define RP1_INT_USBHOST0_1 32
> +#define RP1_INT_USBHOST0_2 33
> +#define RP1_INT_USBHOST0_3 34
> +#define RP1_INT_USBHOST1 35
> +#define RP1_INT_USBHOST1_0 36
> +#define RP1_INT_USBHOST1_1 37
> +#define RP1_INT_USBHOST1_2 38
> +#define RP1_INT_USBHOST1_3 39
> +#define RP1_INT_DMA 40
> +#define RP1_INT_PWM1 41
> +#define RP1_INT_UART1 42
> +#define RP1_INT_UART2 43
> +#define RP1_INT_UART3 44
> +#define RP1_INT_UART4 45
> +#define RP1_INT_UART5 46
> +#define RP1_INT_MIPI0 47
> +#define RP1_INT_MIPI1 48
> +#define RP1_INT_VIDEO_OUT 49
> +#define RP1_INT_PIO_0 50
> +#define RP1_INT_PIO_1 51
> +#define RP1_INT_ADC_FIFO 52
> +#define RP1_INT_PCIE_OUT 53
> +#define RP1_INT_SPI6 54
> +#define RP1_INT_SPI7 55
> +#define RP1_INT_SPI8 56
> +#define RP1_INT_SYSCFG 58
> +#define RP1_INT_CLOCKS_DEFAULT 59
> +#define RP1_INT_VBUSCTRL 60
> +#define RP1_INT_PROC_MISC 57

Why all these defines which will never be used because they come from
DT?

Rob