Add a basic timer device and exercise it during device probing. This
first draft is probably very questionable.
One point in particular which should IMHO receive attention: the generic
wait_on() method aims at providing similar functionality to Nouveau's
nvkm_[num]sec() macros. Since this method will be heavily used with
different conditions to test, I'd like to avoid monomorphizing it
entirely with each instance ; that's something that is achieved in
nvkm_xsec() using functions that the macros invoke.
I have tried achieving the same result in Rust using closures (kept
as-is in the current code), but they seem to be monomorphized as well.
Calling extra functions could work better, but looks also less elegant
to me, so I am really open to suggestions here.
Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
---
drivers/gpu/nova-core/driver.rs | 4 +-
drivers/gpu/nova-core/gpu.rs | 35 ++++++++++++++-
drivers/gpu/nova-core/nova_core.rs | 1 +
drivers/gpu/nova-core/regs.rs | 43 ++++++++++++++++++
drivers/gpu/nova-core/timer.rs | 91 ++++++++++++++++++++++++++++++++++++++
5 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/nova-core/driver.rs b/drivers/gpu/nova-core/driver.rs
index 63c19f140fbdd65d8fccf81669ac590807cc120f..0cd23aa306e4082405f480afc0530a41131485e7 100644
--- a/drivers/gpu/nova-core/driver.rs
+++ b/drivers/gpu/nova-core/driver.rs
@@ -10,7 +10,7 @@ pub(crate) struct NovaCore {
pub(crate) gpu: Gpu,
}
-const BAR0_SIZE: usize = 8;
+const BAR0_SIZE: usize = 0x9500;
pub(crate) type Bar0 = pci::Bar<BAR0_SIZE>;
kernel::pci_device_table!(
@@ -42,6 +42,8 @@ fn probe(pdev: &mut pci::Device, _info: &Self::IdInfo) -> Result<Pin<KBox<Self>>
GFP_KERNEL,
)?;
+ let _ = this.gpu.test_timer();
+
Ok(this)
}
}
diff --git a/drivers/gpu/nova-core/gpu.rs b/drivers/gpu/nova-core/gpu.rs
index e7da6a2fa29d82e9624ba8baa2c7281f38cb3133..2fbf4041f6d421583636c7bede449c3416272301 100644
--- a/drivers/gpu/nova-core/gpu.rs
+++ b/drivers/gpu/nova-core/gpu.rs
@@ -1,12 +1,16 @@
// SPDX-License-Identifier: GPL-2.0
+use kernel::device::Device;
+use kernel::types::ARef;
use kernel::{
device, devres::Devres, error::code::*, firmware, fmt, pci, prelude::*, str::CString,
};
use crate::driver::Bar0;
use crate::regs;
+use crate::timer::Timer;
use core::fmt;
+use core::time::Duration;
/// Enum representation of the GPU chipset.
#[derive(fmt::Debug)]
@@ -165,10 +169,12 @@ fn new(dev: &device::Device, spec: &Spec, ver: &str) -> Result<Firmware> {
/// Structure holding the resources required to operate the GPU.
#[pin_data]
pub(crate) struct Gpu {
+ dev: ARef<Device>,
spec: Spec,
/// MMIO mapping of PCI BAR 0
bar: Devres<Bar0>,
fw: Firmware,
+ timer: Timer,
}
impl Gpu {
@@ -184,6 +190,33 @@ pub(crate) fn new(pdev: &pci::Device, bar: Devres<Bar0>) -> Result<impl PinInit<
spec.revision
);
- Ok(pin_init!(Self { spec, bar, fw }))
+ let dev = pdev.as_ref().into();
+ let timer = Timer::new();
+
+ Ok(pin_init!(Self {
+ dev,
+ spec,
+ bar,
+ fw,
+ timer,
+ }))
+ }
+
+ pub(crate) fn test_timer(&self) -> Result<()> {
+ let bar = self.bar.try_access().ok_or(ENXIO)?;
+
+ dev_info!(&self.dev, "testing timer subdev\n");
+ assert!(matches!(
+ self.timer
+ .wait_on(&bar, Duration::from_millis(10), || Some(())),
+ Ok(())
+ ));
+ assert_eq!(
+ self.timer
+ .wait_on(&bar, Duration::from_millis(10), || Option::<()>::None),
+ Err(ETIMEDOUT)
+ );
+
+ Ok(())
}
}
diff --git a/drivers/gpu/nova-core/nova_core.rs b/drivers/gpu/nova-core/nova_core.rs
index 5d0230042793dae97026146e94f3cdb31ba20642..94b165a340ddfffd448f87cd82200391de075806 100644
--- a/drivers/gpu/nova-core/nova_core.rs
+++ b/drivers/gpu/nova-core/nova_core.rs
@@ -5,6 +5,7 @@
mod driver;
mod gpu;
mod regs;
+mod timer;
kernel::module_pci_driver! {
type: driver::NovaCore,
diff --git a/drivers/gpu/nova-core/regs.rs b/drivers/gpu/nova-core/regs.rs
index f2766f95e9d1eeab6734b18525fe504e1e7ea587..5127cc3454c047d64b7aaf599d8bf5f63a08bdfe 100644
--- a/drivers/gpu/nova-core/regs.rs
+++ b/drivers/gpu/nova-core/regs.rs
@@ -54,3 +54,46 @@ pub(crate) fn major_rev(&self) -> u8 {
((self.0 & BOOT0_MAJOR_REV_MASK) >> BOOT0_MAJOR_REV_SHIFT) as u8
}
}
+
+const PTIMER_TIME_0: usize = 0x00009400;
+const PTIMER_TIME_1: usize = 0x00009410;
+
+#[derive(Copy, Clone, PartialEq, Eq)]
+pub(crate) struct PtimerTime0(u32);
+
+impl PtimerTime0 {
+ #[inline]
+ pub(crate) fn read(bar: &Bar0) -> Self {
+ Self(bar.readl(PTIMER_TIME_0))
+ }
+
+ #[inline]
+ pub(crate) fn write(bar: &Bar0, val: u32) {
+ bar.writel(val, PTIMER_TIME_0)
+ }
+
+ #[inline]
+ pub(crate) fn lo(&self) -> u32 {
+ self.0
+ }
+}
+
+#[derive(Copy, Clone, PartialEq, Eq)]
+pub(crate) struct PtimerTime1(u32);
+
+impl PtimerTime1 {
+ #[inline]
+ pub(crate) fn read(bar: &Bar0) -> Self {
+ Self(bar.readl(PTIMER_TIME_1))
+ }
+
+ #[inline]
+ pub(crate) fn write(bar: &Bar0, val: u32) {
+ bar.writel(val, PTIMER_TIME_1)
+ }
+
+ #[inline]
+ pub(crate) fn hi(&self) -> u32 {
+ self.0
+ }
+}
diff --git a/drivers/gpu/nova-core/timer.rs b/drivers/gpu/nova-core/timer.rs
new file mode 100644
index 0000000000000000000000000000000000000000..f6a787d4fbdb90b3dc13e322d50da1c7f64818df
--- /dev/null
+++ b/drivers/gpu/nova-core/timer.rs
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Nova Core Timer subdevice
+
+use core::time::Duration;
+
+use kernel::num::U64Ext;
+use kernel::prelude::*;
+
+use crate::driver::Bar0;
+use crate::regs;
+
+pub(crate) struct Timer {}
+
+impl Timer {
+ pub(crate) fn new() -> Self {
+ Self {}
+ }
+
+ pub(crate) fn read(bar: &Bar0) -> u64 {
+ loop {
+ let hi = regs::PtimerTime1::read(bar);
+ let lo = regs::PtimerTime0::read(bar);
+
+ if hi == regs::PtimerTime1::read(bar) {
+ return u64::from_u32s(hi.hi(), lo.lo());
+ }
+ }
+ }
+
+ #[allow(dead_code)]
+ pub(crate) fn time(bar: &Bar0, time: u64) {
+ let (hi, lo) = time.into_u32s();
+
+ regs::PtimerTime1::write(bar, hi);
+ regs::PtimerTime0::write(bar, lo);
+ }
+
+ /// Wait until `cond` is true or `timeout` elapsed, based on GPU time.
+ ///
+ /// When `cond` evaluates to `Some`, its return value is returned.
+ ///
+ /// `Err(ETIMEDOUT)` is returned if `timeout` has been reached without `cond` evaluating to
+ /// `Some`, or if the timer device is stuck for some reason.
+ pub(crate) fn wait_on<R, F: Fn() -> Option<R>>(
+ &self,
+ bar: &Bar0,
+ timeout: Duration,
+ cond: F,
+ ) -> Result<R> {
+ // Number of consecutive time reads after which we consider the timer frozen if it hasn't
+ // moved forward.
+ const MAX_STALLED_READS: usize = 16;
+
+ let (mut cur_time, mut prev_time, deadline) = (|| {
+ let cur_time = Timer::read(bar);
+ let deadline =
+ cur_time.saturating_add(u64::try_from(timeout.as_nanos()).unwrap_or(u64::MAX));
+
+ (cur_time, cur_time, deadline)
+ })();
+ let mut num_reads = 0;
+
+ loop {
+ if let Some(ret) = cond() {
+ return Ok(ret);
+ }
+
+ (|| {
+ cur_time = Timer::read(bar);
+
+ /* Check if the timer is frozen for some reason. */
+ if cur_time == prev_time {
+ if num_reads >= MAX_STALLED_READS {
+ return Err(ETIMEDOUT);
+ }
+ num_reads += 1;
+ } else {
+ if cur_time >= deadline {
+ return Err(ETIMEDOUT);
+ }
+
+ num_reads = 0;
+ prev_time = cur_time;
+ }
+
+ Ok(())
+ })()?;
+ }
+ }
+}
--
2.48.1
