[PATCH v6] bus: mhi: host: don't free bhie tables during suspend/hibernation

[Jeff Hugo]

On 5/16/2025 12:49 PM, Muhammad Usama Anjum wrote:
> Fix dma_direct_alloc() failure at resume time during bhie_table
> allocation because of memory pressure. There is a report where at
> resume time, the memory from the dma doesn't get allocated and MHI
> fails to re-initialize.
> 
> To fix it, don't free the memory at power down during suspend /
> hibernation. Instead, use the same allocated memory again after every
> resume / hibernation. This patch has been tested with resume and
> hibernation both.
> 
> Optimize the rddm and fbc bhie allocations. The rddm is of constant
> size for a given hardware. While the fbc_image size depends on the
> firmware. If the firmware changes, we'll free and allocate new memory
> for it. This patch is motivated from the ath12k [1] and ath11k [2]
> patches. They don't free the memory and reuse the same memory if new
> size is same. The firmware caching hasn't been implemented for the
> drivers other than in the nouveau. (The changing of firmware isn't
> tested/supported for wireless drivers. But let's follow the example
> patches here.)
> 
> [1] https://lore.kernel.org/all/20240419034034.2842-1-quic_bqiang@quicinc.com/
> [2] https://lore.kernel.org/all/20220506141448.10340-1-quic_akolli@quicinc.com/
> 
> Tested-on: WCN6855 WLAN.HSP.1.1-03926.13-QCAHSPSWPL_V2_SILICONZ_CE-2.52297.6
> Tested-on: WCN7850 hw2.0 WLAN.HMT.1.1.c5-00284-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3
> 
> Acked-by: Jeff Johnson <jeff.johnson at oss.qualcomm.com>
> Tested-by: Baochen Qiang <quic_bqiang at quicinc.com>
> Signed-off-by: Muhammad Usama Anjum <usama.anjum at collabora.com>

I think we are in a good spot now.

Reviewed-by: Jeff Hugo <jeff.hugo at oss.qualcomm.com>