On Tue, 27 Jul 2021 13:14:08 +0100,
Bixuan Cui <[email protected]> wrote:
>
> Add suspend and resume support for arm-smmu-v3 by low-power mode.
>
> When the smmu is suspended, it is powered off and the registers are
> cleared. So saves the msi_msg context during msi interrupt initialization
> of smmu. When resume happens it calls arm_smmu_device_reset() to restore
> the registers.
>
> Signed-off-by: Bixuan Cui <[email protected]>
> Reviewed-by: Wei Yongjun <[email protected]>
> Reviewed-by: Zhen Lei <[email protected]>
> Reviewed-by: Ding Tianhong <[email protected]>
> Reviewed-by: Hanjun Guo <[email protected]>
> ---
> Changes in v2:
> * Using get_cached_msi_msg() instead of the descriptor to resume msi_msg
> in arm_smmu_resume_msis();
>
> * Move arm_smmu_resume_msis() from arm_smmu_setup_unique_irqs() into
> arm_smmu_setup_irqs() and rename it to arm_smmu_resume_unique_irqs();
>
> Call arm_smmu_setup_unique_irqs() to configure the IRQ during probe and
> call arm_smmu_resume_unique_irqs() in resume mode to restore the IRQ
> registers to make the code more reasonable.
>
> * Call arm_smmu_device_disable() to disable smmu and clear CR0_SMMUEN on
> suspend. Then the warning about CR0_SMMUEN being enabled can be cleared
> on resume.
>
> * Using SET_SYSTEM_SLEEP_PM_OPS();
>
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 69 ++++++++++++++++++---
> 1 file changed, 62 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index 235f9bdaeaf2..66f35d5c7a70 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -40,6 +40,7 @@ MODULE_PARM_DESC(disable_bypass,
>
> static bool disable_msipolling;
> module_param(disable_msipolling, bool, 0444);
> +static bool bypass;
As outlined before, this is likely to be wrong if you can have
per-SMMU bypass control.
> MODULE_PARM_DESC(disable_msipolling,
> "Disable MSI-based polling for CMD_SYNC completion.");
>
> @@ -3129,11 +3130,38 @@ static void arm_smmu_write_msi_msg(struct msi_desc
> *desc, struct msi_msg *msg)
> doorbell = (((u64)msg->address_hi) << 32) | msg->address_lo;
> doorbell &= MSI_CFG0_ADDR_MASK;
>
> + /* Saves the msg context for resume if desc->msg is empty */
> + if (desc->msg.address_lo == 0x0 && desc->msg.address_hi == 0x0) {
> + desc->msg.address_lo = msg->address_lo;
> + desc->msg.address_hi = msg->address_hi;
> + desc->msg.data = msg->data;
> + }
I thought I had made it clear that this approach is not acceptable.
Please fix the generic code to keep track of the latest message.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
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