mirror of https://github.com/torvalds/linux.git
72 lines
3.1 KiB
Rust
72 lines
3.1 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
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//! GPU Firmware (`GFW`) support, a.k.a `devinit`.
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//!
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//! Upon reset, the GPU runs some firmware code from the BIOS to setup its core parameters. Most of
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//! the GPU is considered unusable until this step is completed, so we must wait on it before
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//! performing driver initialization.
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//!
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//! A clarification about devinit terminology: devinit is a sequence of register read/writes after
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//! reset that performs tasks such as:
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//! 1. Programming VRAM memory controller timings.
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//! 2. Power sequencing.
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//! 3. Clock and PLL configuration.
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//! 4. Thermal management.
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//!
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//! devinit itself is a 'script' which is interpreted by an interpreter program typically running
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//! on the PMU microcontroller.
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//!
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//! Note that the devinit sequence also needs to run during suspend/resume.
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use kernel::{
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io::poll::read_poll_timeout,
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prelude::*,
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time::Delta, //
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};
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use crate::{
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driver::Bar0,
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regs, //
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};
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/// Wait for the `GFW` (GPU firmware) boot completion signal (`GFW_BOOT`), or a 4 seconds timeout.
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///
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/// Upon GPU reset, several microcontrollers (such as PMU, SEC2, GSP etc) run some firmware code to
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/// setup its core parameters. Most of the GPU is considered unusable until this step is completed,
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/// so it must be waited on very early during driver initialization.
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///
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/// The `GFW` code includes several components that need to execute before the driver loads. These
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/// components are located in the VBIOS ROM and executed in a sequence on these different
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/// microcontrollers. The devinit sequence typically runs on the PMU, and the FWSEC runs on the
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/// GSP.
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///
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/// This function waits for a signal indicating that core initialization is complete. Before this
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/// signal is received, little can be done with the GPU. This signal is set by the FWSEC running on
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/// the GSP in Heavy-secured mode.
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pub(crate) fn wait_gfw_boot_completion(bar: &Bar0) -> Result {
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// Before accessing the completion status in `NV_PGC6_AON_SECURE_SCRATCH_GROUP_05`, we must
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// first check `NV_PGC6_AON_SECURE_SCRATCH_GROUP_05_PRIV_LEVEL_MASK`. This is because
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// `NV_PGC6_AON_SECURE_SCRATCH_GROUP_05` becomes accessible only after the secure firmware
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// (FWSEC) lowers the privilege level to allow CPU (LS/Light-secured) access. We can only
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// safely read the status register from CPU (LS/Light-secured) once the mask indicates
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// that the privilege level has been lowered.
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//
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// TIMEOUT: arbitrarily large value. GFW starts running immediately after the GPU is put out of
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// reset, and should complete in less time than that.
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read_poll_timeout(
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|| {
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Ok(
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// Check that FWSEC has lowered its protection level before reading the GFW_BOOT
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// status.
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regs::NV_PGC6_AON_SECURE_SCRATCH_GROUP_05_PRIV_LEVEL_MASK::read(bar)
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.read_protection_level0()
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&& regs::NV_PGC6_AON_SECURE_SCRATCH_GROUP_05_0_GFW_BOOT::read(bar).completed(),
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)
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},
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|&gfw_booted| gfw_booted,
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Delta::from_millis(1),
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Delta::from_secs(4),
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)
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.map(|_| ())
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}
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