[PATCH v3] bus: mhi: host: don't free bhie tables during suspend/hibernation

[Muhammad Usama Anjum <usama.anjum@collabora.com>]

Fix dma_direct_alloc() failure at resume time during bhie_table
allocation. There is a crash report where at resume time, the memory
from the dma doesn't get allocated and MHI fails to re-initialize.
There is fragmentation/memory pressure.

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.

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.

Here are the crash logs:

[ 3029.338587] mhi mhi0: Requested to power ON
[ 3029.338621] mhi mhi0: Power on setup success
[ 3029.668654] kworker/u33:8: page allocation failure: order:7, mode:0xc04(GFP_NOIO|GFP_DMA32), nodemask=(null),cpuset=/,mems_allowed=0
[ 3029.668682] CPU: 4 UID: 0 PID: 2744 Comm: kworker/u33:8 Not tainted 6.11.11-valve10-1-neptune-611-gb69e902b4338 #1ed779c892334112fb968aaa3facf9686b5ff0bd7
[ 3029.668690] Hardware name: Valve Galileo/Galileo, BIOS F7G0112 08/01/2024
[ 3029.668694] Workqueue: mhi_hiprio_wq mhi_pm_st_worker [mhi]
[ 3029.668717] Call Trace:
[ 3029.668722]  <TASK>
[ 3029.668728]  dump_stack_lvl+0x4e/0x70
[ 3029.668738]  warn_alloc+0x164/0x190
[ 3029.668747]  ? srso_return_thunk+0x5/0x5f
[ 3029.668754]  ? __alloc_pages_direct_compact+0xaf/0x360
[ 3029.668761]  __alloc_pages_slowpath.constprop.0+0xc75/0xd70
[ 3029.668774]  __alloc_pages_noprof+0x321/0x350
[ 3029.668782]  __dma_direct_alloc_pages.isra.0+0x14a/0x290
[ 3029.668790]  dma_direct_alloc+0x70/0x270
[ 3029.668796]  mhi_alloc_bhie_table+0xe8/0x190 [mhi faa917c5aa23a5f5b12d6a2c597067e16d2fedc0]
[ 3029.668814]  mhi_fw_load_handler+0x1bc/0x310 [mhi faa917c5aa23a5f5b12d6a2c597067e16d2fedc0]
[ 3029.668830]  mhi_pm_st_worker+0x5c8/0xaa0 [mhi faa917c5aa23a5f5b12d6a2c597067e16d2fedc0]
[ 3029.668844]  ? srso_return_thunk+0x5/0x5f
[ 3029.668853]  process_one_work+0x17e/0x330
[ 3029.668861]  worker_thread+0x2ce/0x3f0
[ 3029.668868]  ? __pfx_worker_thread+0x10/0x10
[ 3029.668873]  kthread+0xd2/0x100
[ 3029.668879]  ? __pfx_kthread+0x10/0x10
[ 3029.668885]  ret_from_fork+0x34/0x50
[ 3029.668892]  ? __pfx_kthread+0x10/0x10
[ 3029.668898]  ret_from_fork_asm+0x1a/0x30
[ 3029.668910]  </TASK>

Tested-on: WCN6855 WLAN.HSP.1.1-03926.13-QCAHSPSWPL_V2_SILICONZ_CE-2.52297.6

Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
---
Changes since v1:
- Don't free bhie tables during suspend/hibernation only
- Handle fbc_image changed size correctly
- Remove fbc_image getting set to NULL in *free_bhie_table()

Changes since v2:
- Remove the new mhi_partial_unprepare_after_power_down() and instead
  update mhi_power_down_keep_dev() to use
  mhi_power_down_unprepare_keep_dev() as suggested by Mani
- Update all users of this API such as ath12k (previously only ath11k
  was updated)
- Define prev_fw_sz in docs
- Do better alignment of comments

Tested on ath11k.
---
 drivers/bus/mhi/host/boot.c           | 15 +++++++++++----
 drivers/bus/mhi/host/init.c           |  5 +++--
 drivers/bus/mhi/host/pm.c             |  9 +++++++++
 drivers/net/wireless/ath/ath11k/mhi.c |  8 ++++----
 drivers/net/wireless/ath/ath12k/mhi.c |  8 ++++----
 include/linux/mhi.h                   |  2 ++
 6 files changed, 33 insertions(+), 14 deletions(-)

diff --git a/drivers/bus/mhi/host/boot.c b/drivers/bus/mhi/host/boot.c
index efa3b6dddf4d2..bc8459798bbee 100644
--- a/drivers/bus/mhi/host/boot.c
+++ b/drivers/bus/mhi/host/boot.c
@@ -584,10 +584,17 @@ void mhi_fw_load_handler(struct mhi_controller *mhi_cntrl)
 	 * device transitioning into MHI READY state
 	 */
 	if (fw_load_type == MHI_FW_LOAD_FBC) {
-		ret = mhi_alloc_bhie_table(mhi_cntrl, &mhi_cntrl->fbc_image, fw_sz);
-		if (ret) {
-			release_firmware(firmware);
-			goto error_fw_load;
+		if (mhi_cntrl->fbc_image && fw_sz != mhi_cntrl->prev_fw_sz) {
+			mhi_free_bhie_table(mhi_cntrl, mhi_cntrl->fbc_image);
+			mhi_cntrl->fbc_image = NULL;
+		}
+		if (!mhi_cntrl->fbc_image) {
+			ret = mhi_alloc_bhie_table(mhi_cntrl, &mhi_cntrl->fbc_image, fw_sz);
+			if (ret) {
+				release_firmware(firmware);
+				goto error_fw_load;
+			}
+			mhi_cntrl->prev_fw_sz = fw_sz;
 		}
 
 		/* Load the firmware into BHIE vec table */
diff --git a/drivers/bus/mhi/host/init.c b/drivers/bus/mhi/host/init.c
index 13e7a55f54ff4..a7663ad16bfc6 100644
--- a/drivers/bus/mhi/host/init.c
+++ b/drivers/bus/mhi/host/init.c
@@ -1173,8 +1173,9 @@ int mhi_prepare_for_power_up(struct mhi_controller *mhi_cntrl)
 		/*
 		 * Allocate RDDM table for debugging purpose if specified
 		 */
-		mhi_alloc_bhie_table(mhi_cntrl, &mhi_cntrl->rddm_image,
-				     mhi_cntrl->rddm_size);
+		if (!mhi_cntrl->rddm_image)
+			mhi_alloc_bhie_table(mhi_cntrl, &mhi_cntrl->rddm_image,
+					     mhi_cntrl->rddm_size);
 		if (mhi_cntrl->rddm_image) {
 			ret = mhi_rddm_prepare(mhi_cntrl,
 					       mhi_cntrl->rddm_image);
diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c
index e6c3ff62bab1d..b726b000d8a5d 100644
--- a/drivers/bus/mhi/host/pm.c
+++ b/drivers/bus/mhi/host/pm.c
@@ -1259,10 +1259,19 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
 }
 EXPORT_SYMBOL_GPL(mhi_power_down);
 
+void mhi_power_down_unprepare_keep_dev(struct mhi_controller *mhi_cntrl)
+{
+	mhi_cntrl->bhi = NULL;
+	mhi_cntrl->bhie = NULL;
+
+	mhi_deinit_dev_ctxt(mhi_cntrl);
+}
+
 void mhi_power_down_keep_dev(struct mhi_controller *mhi_cntrl,
 			       bool graceful)
 {
 	__mhi_power_down(mhi_cntrl, graceful, false);
+	mhi_power_down_unprepare_keep_dev(mhi_cntrl);
 }
 EXPORT_SYMBOL_GPL(mhi_power_down_keep_dev);
 
diff --git a/drivers/net/wireless/ath/ath11k/mhi.c b/drivers/net/wireless/ath/ath11k/mhi.c
index acd76e9392d31..c5dc776b23643 100644
--- a/drivers/net/wireless/ath/ath11k/mhi.c
+++ b/drivers/net/wireless/ath/ath11k/mhi.c
@@ -460,12 +460,12 @@ void ath11k_mhi_stop(struct ath11k_pci *ab_pci, bool is_suspend)
 	 * workaround, otherwise ath11k_core_resume() will timeout
 	 * during resume.
 	 */
-	if (is_suspend)
+	if (is_suspend) {
 		mhi_power_down_keep_dev(ab_pci->mhi_ctrl, true);
-	else
+	} else {
 		mhi_power_down(ab_pci->mhi_ctrl, true);
-
-	mhi_unprepare_after_power_down(ab_pci->mhi_ctrl);
+		mhi_unprepare_after_power_down(ab_pci->mhi_ctrl);
+	}
 }
 
 int ath11k_mhi_suspend(struct ath11k_pci *ab_pci)
diff --git a/drivers/net/wireless/ath/ath12k/mhi.c b/drivers/net/wireless/ath/ath12k/mhi.c
index 08f44baf182a5..cb7f789d873f2 100644
--- a/drivers/net/wireless/ath/ath12k/mhi.c
+++ b/drivers/net/wireless/ath/ath12k/mhi.c
@@ -635,12 +635,12 @@ void ath12k_mhi_stop(struct ath12k_pci *ab_pci, bool is_suspend)
 	 * workaround, otherwise ath12k_core_resume() will timeout
 	 * during resume.
 	 */
-	if (is_suspend)
+	if (is_suspend) {
 		ath12k_mhi_set_state(ab_pci, ATH12K_MHI_POWER_OFF_KEEP_DEV);
-	else
+	} else {
 		ath12k_mhi_set_state(ab_pci, ATH12K_MHI_POWER_OFF);
-
-	ath12k_mhi_set_state(ab_pci, ATH12K_MHI_DEINIT);
+		ath12k_mhi_set_state(ab_pci, ATH12K_MHI_DEINIT);
+	}
 }
 
 void ath12k_mhi_suspend(struct ath12k_pci *ab_pci)
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index dd372b0123a6d..6fd218a877855 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -306,6 +306,7 @@ struct mhi_controller_config {
  *           if fw_image is NULL and fbc_download is true (optional)
  * @fw_sz: Firmware image data size for normal booting, used only if fw_image
  *         is NULL and fbc_download is true (optional)
+ * @prev_fw_sz: Previous firmware image data size, when fbc_download is true
  * @edl_image: Firmware image name for emergency download mode (optional)
  * @rddm_size: RAM dump size that host should allocate for debugging purpose
  * @sbl_size: SBL image size downloaded through BHIe (optional)
@@ -382,6 +383,7 @@ struct mhi_controller {
 	const char *fw_image;
 	const u8 *fw_data;
 	size_t fw_sz;
+	size_t prev_fw_sz;
 	const char *edl_image;
 	size_t rddm_size;
 	size_t sbl_size;
-- 
2.43.0