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Linux RISC-V AIA Support #542

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@bjoto bjoto commented Jan 27, 2024

Pull request for series with
subject: Linux RISC-V AIA Support
version: 12
url: https://patchwork.kernel.org/project/linux-riscv/list/?series=820545

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bjoto commented Jan 27, 2024

Upstream branch: cb4ede9
series: https://patchwork.kernel.org/project/linux-riscv/list/?series=820545
version: 12

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bjoto commented Jan 27, 2024

Upstream branch: cb4ede9
series: https://patchwork.kernel.org/project/linux-riscv/list/?series=820545
version: 12

Thomas Gleixner and others added 20 commits January 27, 2024 17:44
…r count

Currently the irqdomain select callback is only invoked when the parameter
count of the fwspec arguments is not zero. That makes sense because then
the match is on the firmware node and eventually on the bus_token, which is
already handled in the core code.

The upcoming support for per device MSI domains requires to do real bus
token specific checks in the MSI parent domains with a zero parameter
count.

Make the gic-v3 select() callback handle that case.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Now that the GIC-v3 callback can handle invocation with a fwspec parameter
count of 0 lift the restriction in the core code and invoke select()
unconditionally when the domain provides it.

Preparatory change for per device MSI domains.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Supporting per device MSI domains on ARM64, RISC-V and the zoo of
interrupt mechanisms needs a bit more information than what the
initial x86 implementation provides.

Add the following fields:

  - required_flags: 	The flags which a parent domain requires to be set
  - bus_select_token:	The bus token of the parent domain for select()
  - bus_select_mask:	A bitmask of supported child domain bus types

This allows to provide library functions which can be shared between
various interrupt chip implementations and avoids replicating mostly
similar code all over the place.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Add a new domain bus token to prepare for device MSI which aims to replace
the existing platform MSI maze.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Provide functions to create and remove per device MSI domains which replace
the platform-MSI domains. The new model is that each of the devices which
utilize platform-MSI gets now its private MSI domain which is "customized"
in size and with a device specific function to write the MSI message into
the device.

This is the same functionality as platform-MSI but it avoids all the down
sides of platform MSI, i.e. the extra ID book keeping, the special data
structure in the msi descriptor. Further the domains are only created when
the devices are really in use, so the burden is on the usage and not on the
infrastructure.

Fill in the domain template and provide two functions to init/allocate and
remove a per device MSI domain.

Until all users and parent domain providers are converted, the init/alloc
function invokes the original platform-MSI code when the irqdomain which is
associated to the device does not provide MSI parent functionality yet.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Switch all the users of the platform MSI domain over to invoke the new
interfaces which branch to the original platform MSI functions when the
irqdomain associated to the caller device does not yet provide MSI parent
functionality.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Sinan Kaya <okaya@kernel.org>
Cc: Andy Gross <agross@kernel.org>
Cc: Bjorn Andersson <andersson@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
irq_create_fwspec_mapping() requires translation of the firmware spec to a
hardware interrupt number and the trigger type information.

Wired interrupts which are connected to a wire to MSI bridge, like MBIGEN
are allocated that way. So far MBIGEN provides a regular irqdomain which
then hooks backwards into the MSI infrastructure. That's an unholy mess and
will be replaced with per device MSI domains which are regular MSI domains.

Interrupts on MSI domains are not supported by irq_create_fwspec_mapping(),
but for making the wire to MSI bridges sane it makes sense to provide a
special allocation/free interface in the MSI infrastructure. That avoids
the backdoors into the core MSI allocation code and just shares all the
regular MSI infrastructure.

Provide an optional translation callback in msi_domain_ops which can be
utilized by these wire to MSI bridges. No other MSI domain should provide a
translation callback. The default translation callback of the MSI
irqdomains will warn when it is invoked on a non-prepared MSI domain.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
In preparation for providing a special allocation function for wired
interrupt which are connected to a wire to MSI bridge, split the inner
workings of msi_domain_alloc_irq_at() out into a helper function so the
code can be shared.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Provide a domain bus token for the upcoming support for wire to MSI device
domains so the domain can be distinguished from regular device MSI domains.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
To support wire to MSI domains via the MSI infrastructure it is required to
use the firmware node of the device which implements this for creating the
MSI domain. Otherwise the existing firmware match mechanisms to find the
correct irqdomain for a wired interrupt which is connected to a wire to MSI
bridge would fail.

This cannot be used for the general case because not all devices provide
firmware nodes and all regular per device MSI domains are directly
associated to the device and have not be searched for.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
To support wire to MSI bridges proper in the MSI core infrastructure it is
required to have separate allocation/free interfaces which can be invoked
from the regular irqdomain allocaton/free functions.

The mechanism for allocation is:
  - Allocate the next free MSI descriptor index in the domain
  - Store the hardware interrupt number and the trigger type
    which was extracted by the irqdomain core from the firmware spec
    in the MSI descriptor device cookie so it can be retrieved by
    the underlying interrupt domain and interrupt chip
  - Use the regular MSI allocation mechanism for the newly allocated
    index which returns a fully initialized Linux interrupt on succes

This works because:
  - the domains have a fixed size
  - each hardware interrupt is only allocated once
  - the underlying domain does not care about the MSI index it only cares
    about the hardware interrupt number and the trigger type

The free function looks up the MSI index in the MSI descriptor of the
provided Linux interrupt number and uses the regular index based free
functions of the MSI core.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Reroute interrupt allocation in irq_create_fwspec_mapping() if the domain
is a MSI device domain. This is required to convert the support for wire
to MSI bridges to per device MSI domains.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Some platform-MSI implementations require that power management is
redirected to the underlying interrupt chip device. To make this work
with per device MSI domains provide a new feature flag and let the
core code handle the setup of dev->pm_dev when set during device MSI
domain creation.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
The PLIC driver does not require very early initialization so let
us convert it into a platform driver.

As part of the conversion, the PLIC probing undergoes the following
changes:
1. Use dev_info(), dev_err() and dev_warn() instead of pr_info(),
   pr_err() and pr_warn()
2. Use devm_xyz() APIs wherever applicable
3. PLIC is now probed after CPUs are brought-up so we have to
   setup cpuhp state after context handler of all online CPUs
   are initialized otherwise we see crash on multi-socket systems

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
The RISC-V advanced interrupt architecture (AIA) extends the per-HART
local interrupts in following ways:
1. Minimum 64 local interrupts for both RV32 and RV64
2. Ability to process multiple pending local interrupts in same
   interrupt handler
3. Priority configuration for each local interrupts
4. Special CSRs to configure/access the per-HART MSI controller

We add support for #1 and #2 described above in the RISC-V intc driver.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
We add DT bindings document for the RISC-V incoming MSI controller
(IMSIC) defined by the RISC-V advanced interrupt architecture (AIA)
specification.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Some (future) users of the irq matrix allocator, do not know the size
of the matrix bitmaps at compile time.

To avoid wasting memory on unnecessary large bitmaps, size the bitmap
at matrix allocation time.

Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
The RISC-V advanced interrupt architecture (AIA) specification
defines a new MSI controller called incoming message signalled
interrupt controller (IMSIC) which manages MSI on per-HART (or
per-CPU) basis. It also supports IPIs as software injected MSIs.
(For more details refer https://github.com/riscv/riscv-aia)

Let us add an early irqchip driver for RISC-V IMSIC which sets
up the IMSIC state and provide IPIs.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
The Linux platform MSI support allows per-device MSI domains so let
us add a platform irqchip driver for RISC-V IMSIC which provides a
base IRQ domain with MSI parent support for platform device domains.

This driver assumes that the IMSIC state is already initialized by
the IMSIC early driver.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
The Linux PCI framework supports per-device MSI domains for PCI devices
so let us extend the IMSIC driver to allow per-device MSI domains for
PCI devices.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
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bjoto commented Jan 27, 2024

Upstream branch: cb4ede9
series: https://patchwork.kernel.org/project/linux-riscv/list/?series=820545
version: 12

We add DT bindings document for RISC-V advanced platform level interrupt
controller (APLIC) defined by the RISC-V advanced interrupt architecture
(AIA) specification.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
The RISC-V advanced interrupt architecture (AIA) specification defines
advanced platform-level interrupt controller (APLIC) which has two modes
of operation: 1) Direct mode and 2) MSI mode.
(For more details, refer https://github.com/riscv/riscv-aia)

In APLIC direct-mode, wired interrupts are forwared to CPUs (or HARTs)
as a local external interrupt.

We add a platform irqchip driver for the RISC-V APLIC direct-mode to
support RISC-V platforms having only wired interrupts.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
The RISC-V advanced platform-level interrupt controller (APLIC) has
two modes of operation: 1) Direct mode and 2) MSI mode.
(For more details, refer https://github.com/riscv/riscv-aia)

In APLIC MSI-mode, wired interrupts are forwared as message signaled
interrupts (MSIs) to CPUs via IMSIC.

We extend the existing APLIC irqchip driver to support MSI-mode for
RISC-V platforms having both wired interrupts and MSIs.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
The QEMU virt machine supports AIA emulation and we also have
quite a few RISC-V platforms with AIA support under development
so let us select APLIC and IMSIC drivers for all RISC-V platforms.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Add myself as maintainer for RISC-V AIA drivers including the
RISC-V INTC driver which supports both AIA and non-AIA platforms.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
@bjoto
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bjoto commented Feb 9, 2024

At least one diff in series https://patchwork.kernel.org/project/linux-riscv/list/?series=820545 expired. Closing PR.

@bjoto bjoto closed this Feb 9, 2024
@bjoto bjoto deleted the series/694336=>for-next branch February 12, 2024 20:03
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