Add D1's nonretentive suspend state to the devicetree so S-mode software
knows about it and can use it.
Latency and power measurements were taken on an Allwinner Nezha board:
- Entry latency was measured from the beginning of sbi_ecall_handler()
to before the call to wfi() in sun20i_d1_hart_suspend().
- Exit latency was measured from the beginning of sbi_init() to before
the call to sbi_hart_switch_mode() in init_warmboot().
- There was a 17.5 mW benefit from non-retentive suspend compared to
WFI, with a 170 mW cost during the 107 us entry/exit period. This
provides a break-even point around 1040 us. Residency includes entry
latency, so round this up to 1100 us.
- The hardware power sequence latency (after the WFI) is assumed to be
negligible, so set the wakeup latency to the exit latency.
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Samuel Holland <samuel@sholland.org>
Since the availability and latency properties of CPU idle states depend
on the specific SBI HSM implementation, it is appropriate that the idle
states are added to the devicetree at runtime by that implementation.
This helper function adds a platform-provided array of idle states to
the devicetree, following the SBI idle state binding.
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Samuel Holland <samuel@sholland.org>
The two referenced commits passed incorrect bounds to the PLIC save/
restore functions, causing out-of-bounds memory access. The functions
expect "num" to be the 1-based number of interrupt sources, equivalent
to the "riscv,ndev" devicetree property. Thus, "num" must be strictly
smaller than the 0-based size of the array storing the register values.
However, the referenced commits incorrectly passed in the unmodified
size of the array as "num". Fix this by reducing PLIC_SOURCES (matching
"riscv,ndev" on this platform), while keeping the same array sizes.
Addresses-Coverity-ID: 1530251 ("Out-of-bounds access")
Addresses-Coverity-ID: 1530252 ("Out-of-bounds access")
Fixes: 8509e46ca6 ("lib: utils/irqchip: plic: Ensure no out-of-bound access in priority save/restore helpers")
Fixes: 9a2eeb4aae ("lib: utils/irqchip: plic: Ensure no out-of-bound access in context save/restore helpers")
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Anup Patel <anup@brainfault.org>
The allwinner,sun20i-d1-clint compatible string is not documented in any
official binding, so it should not be used by drivers.
The MSWI in the D1 CLINT is compatible with the ACLINT specification, so
it can take advantage of generic driver support. However, that is only
possible if the MSWI and MTIMER are split into separate DT nodes. This
means the final binding for this device is likely to be incompatible
with what is implemented here.
Remove this compatible string from the driver to prevent it from
appearing in a stable version and causing future issues.
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Anup Patel <anup@brainfault.org>
The CLINT in the Allwinner D1 SoC apparently does not support 64-bit
MMIO access. A property was added to support this quirk (and that
property was copied to the ACLINT MTIMER code). However, since this
difference in behavior makes the D1 CLINT incompatible with the SiFive
CLINT's programming interface, a better solution is to use a separate
compatible string.
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Anup Patel <anup@brainfault.org>
Allwinner D1 contains a "PPU" power domain controller which can
automatically power down/up the CPU power domain. This power domain
includes the C906 core along with its CLINT and PLIC.
This HSM implementation supports non-retentive hart suspend by:
1) Saving/restoring state that is lost during hart suspend,
2) Performing cache maintenance before/after hart suspend,
3) Configuring wakeup sources before hart suspend, and
4) Asking the PPU to power down the hart when it enters WFI.
Since this HSM implementation is for a single-core SoC, it does not need
to worry about concurrency or saving multiple instances of state.
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Samuel Holland <samuel@sholland.org>
The delegation bit is lost along with the rest of the PLIC state when
the CPU power domain in the Allwinner D1 is powered down, so the PLIC
needs to be re-delegated to S-mode during the hart resume path.
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Samuel Holland <samuel@sholland.org>
These functions save/restore the state of the PLIC associated with the
current hart. The context save/restore functions only manipulate a
single context, since most likely the M-mode context is unused and does
not need to be saved.
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Anup Patel <anup@brainfault.org>
These can be used by platform code to save the PLIC priority state, if
it would otherwise be lost during non-retentive suspend. The platform
is responsible for allocating all necessary storage.
As a space optimization, store the saved priority values as 8-bit
integers, since that is large enough to hold any priority value on the
relevant platforms.
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Samuel Holland <samuel@sholland.org>
These can be used by platform code to save the PLIC context state, if
it would otherwise be lost during non-retentive suspend. The platform
is responsible for allocating all necessary storage.
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Samuel Holland <samuel@sholland.org>
This simplifies both the callers and the callees by removing duplicated
code and consolidating the error handling. It also fixes two bugs in the
process:
1) ie_words was one too large when plic->num_src was a multiple of 32.
2) plic_set_ie takes a 32-bit mask, not a Boolean value, so the FPGA
platforms previously only enabled one out of every 32 interrupts.
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Samuel Holland <samuel@sholland.org>
None of the functions modify the passed-in plic_data, so mark it const.
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Samuel Holland <samuel@sholland.org>
The suspend code needs to know the resume address for two reasons:
1) Programming some hardware register or management firmware. Here we
assume the hardware/firmware maintains its state between suspends,
so it only needs to be programmed once at startup.
2) When a non-retentive suspend request ends up being retentive, due
to lack of hardware support, pending interrupt, or for some other
reason. However, the behavior here is not platform-dependent, and
this can be handled in the generic hart suspend function.
Since neither situation requires the platform-level suspend function to
know the resume address, stop passing it to that function. Instead,
handle the non-retentive to retentive situation generically.
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Samuel Holland <samuel@sholland.org>
Non-retentive suspend states may require platform-specific actions
during resume. For example, firmware may need to save and restore the
values of custom CSRs. Add a hook to support this.
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Samuel Holland <samuel@sholland.org>
The device's timer_value callback is already the right prototype to use
for the get_time_val function pointer.
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Anup Patel <anup@brainfault.org>
Match data stores hardware attributes which do not change at runtime, so
it does not need to be mutable. Make it const.
Reviewed-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Samuel Holland <samuel@sholland.org>
The T-HEAD PLIC implementation requires setting a delegation bit
to allow access from S-mode. Now that the T-HEAD PLIC has its own
compatible string, set this bit automatically from the PLIC driver,
instead of reaching into the PLIC's MMIO space from another driver.
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
One of the watchdogs in the D1 SoC provides a "soft reset" function,
which allows software to immediately reset the entire SoC. Add a driver
so it can implement the SBI system reset function.
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
In preparation for adding a new fdt_reset driver, ensure the existing
lists are sorted alphabetically.
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
It can be useful to make SBI v0.2 or newer ecalls from this payload
for testing purposes. To support this, convert the macros to use the
extension/function parameter convention.
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
commit 764a17d852 ("lib: sbi: Implement firmware counters") added
switch cases for CAUSE_LOAD_ACCESS and CAUSE_STORE_ACCESS. This caused
them to stop being redirected to U or S mode, as that is handled in the
default switch case. As a result, an error in userspace could cause the
system to hang. Fix this by allowing the acces fault case to fall
through to the default case.
Fixes: 764a17d852 ("lib: sbi: Implement firmware counters")
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
