70bf97de7a4f19cddacc9ebc08dd6e101b534886ed0a8eda33a43645.patch

From f10a5c03b4eef5d769a32638f6e5e4d41d023bb3 Mon Sep 17 00:00:00 2001
From: Yong Wu <yong.wu@mediatek.com>
Date: Fri, 12 Nov 2021 18:54:59 +0800
Subject: [PATCH] FROMGIT: iommu/mediatek: Add device_link between the consumer
 and the larb devices

MediaTek IOMMU-SMI diagram is like below. all the consumer connect with
smi-larb, then connect with smi-common.

        M4U
         |
    smi-common
         |
  -------------
  |         |    ...
  |         |
larb1     larb2
  |         |
vdec       venc

When the consumer works, it should enable the smi-larb's power which
also need enable the smi-common's power firstly.

Thus, First of all, use the device link connect the consumer and the
smi-larbs. then add device link between the smi-larb and smi-common.

This patch adds device_link between the consumer and the larbs.

When device_link_add, I add the flag DL_FLAG_STATELESS to avoid calling
pm_runtime_xx to keep the original status of clocks. It can avoid two
issues:
1) Display HW show fastlogo abnormally reported in [1]. At the beggining,
all the clocks are enabled before entering kernel, but the clocks for
display HW(always in larb0) will be gated after clk_enable and clk_disable
called from device_link_add(->pm_runtime_resume) and rpm_idle. The clock
operation happened before display driver probe. At that time, the display
HW will be abnormal.

2) A deadlock issue reported in [2]. Use DL_FLAG_STATELESS to skip
pm_runtime_xx to avoid the deadlock.

Corresponding, DL_FLAG_AUTOREMOVE_CONSUMER can't be added, then
device_link_removed should be added explicitly.

Meanwhile, Currently we don't have a device connect with 2 larbs at the
same time. Disallow this case, print the error log.

[1] https://lore.kernel.org/linux-mediatek/1564213888.22908.4.camel@mhfsdcap03/
[2] https://lore.kernel.org/patchwork/patch/1086569/

Suggested-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Tested-by: Frank Wunderlich <frank-w@public-files.de> # BPI-R2/MT7623
Acked-by: Joerg Roedel <jroedel@suse.de>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
(cherry picked from commit e78e915dd3764a0369f1247c269f8fec566589d1
 https://git.linuxtv.org/hverkuil/media_tree.git for-v5.18g)

BUG=b:126008328
TEST=emerge-corsola sys-kernel/chromeos-kernel-5_15 succeeds

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Change-Id: I32fe040f631ff37dbdd0d06ece90d05cbd909138
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/3455583
Reviewed-by: Hsin-Yi Wang <hsinyi@chromium.org>
Commit-Queue: Hsin-Yi Wang <hsinyi@chromium.org>
Tested-by: Hsin-Yi Wang <hsinyi@chromium.org>
---
 drivers/iommu/mtk_iommu.c    | 10 +++++++++-
 drivers/iommu/mtk_iommu_v1.c | 11 ++++++++++-
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 7d07135b6d2b..5e4ddd22f12d 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -564,7 +564,7 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
 	struct mtk_iommu_data *data;
 	struct device_link *link;
 	struct device *larbdev;
-	unsigned int larbid;
+	unsigned int larbid, larbidx, i;
 
 	if (!fwspec || fwspec->ops != &mtk_iommu_ops)
 		return ERR_PTR(-ENODEV); /* Not a iommu client device */
@@ -577,6 +577,14 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
 	 * one larb here.
 	 */
 	larbid = MTK_M4U_TO_LARB(fwspec->ids[0]);
+	for (i = 1; i < fwspec->num_ids; i++) {
+		larbidx = MTK_M4U_TO_LARB(fwspec->ids[i]);
+		if (larbid != larbidx) {
+			dev_err(dev, "Can only use one larb. Fail@larb%d-%d.\n",
+				larbid, larbidx);
+			return ERR_PTR(-EINVAL);
+		}
+	}
 	larbdev = data->larb_imu[larbid].dev;
 	link = device_link_add(dev, larbdev,
 			       DL_FLAG_PM_RUNTIME | DL_FLAG_STATELESS);
diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
index 5330c4e7c2e7..cf397436a379 100644
--- a/drivers/iommu/mtk_iommu_v1.c
+++ b/drivers/iommu/mtk_iommu_v1.c
@@ -425,7 +425,7 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
 	struct mtk_iommu_data *data;
 	struct device_link *link;
 	struct device *larbdev;
-	int err, larbid, idx = 0;
+	int err, larbid, idx = 0, larbidx;
 
 	/*
 	 * In the deferred case, free the existed fwspec.
@@ -457,6 +457,15 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
 
 	/* Link the consumer device with the smi-larb device(supplier) */
 	larbid = mt2701_m4u_to_larb(fwspec->ids[0]);
+	for (idx = 1; idx < fwspec->num_ids; idx++) {
+		larbidx = mt2701_m4u_to_larb(fwspec->ids[idx]);
+		if (larbid != larbidx) {
+			dev_err(dev, "Can only use one larb. Fail@larb%d-%d.\n",
+				larbid, larbidx);
+			return ERR_PTR(-EINVAL);
+		}
+	}
+
 	larbdev = data->larb_imu[larbid].dev;
 	link = device_link_add(dev, larbdev,
 			       DL_FLAG_PM_RUNTIME | DL_FLAG_STATELESS);
-- 
2.35.1.473.g83b2b277ed-goog