linux-kernel - [PATCH v4 9/9] drm/tegra: vic: Implement get_streamid

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Date:   Tue,  1 Mar 2022 18:14:55 +0200
From:   cyndis@...si.fi
To:     thierry.reding@...il.com, jonathanh@...dia.com, joro@...tes.org,
        will@...nel.org, robin.murphy@....com, robh+dt@...nel.org,
        krzysztof.kozlowski@...onical.com
Cc:     linux-tegra@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Mikko Perttunen <mperttunen@...dia.com>
Subject: [PATCH v4 9/9] drm/tegra: vic: Implement get_streamid_offset

From: Mikko Perttunen <mperttunen@...dia.com>

Implement the get_streamid_offset required for supporting context
isolation. Since old firmware cannot support context isolation
without hacks that we don't want to implement, check the firmware
binary to see if context isolation should be enabled.

Signed-off-by: Mikko Perttunen <mperttunen@...dia.com>
---
v4:
* Add locking in vic_load_firmware
* Return -EOPNOTSUPP if context isolation is not available
* Update for changed get_streamid_offset declaration
* Add comment noting that vic_load_firmware is safe to call
  without the hardware being powered on
---
 drivers/gpu/drm/tegra/vic.c | 68 ++++++++++++++++++++++++++++++++-----
 1 file changed, 60 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/tegra/vic.c b/drivers/gpu/drm/tegra/vic.c
index 1e342fa3d27b..61eb0407de2a 100644
--- a/drivers/gpu/drm/tegra/vic.c
+++ b/drivers/gpu/drm/tegra/vic.c
@@ -38,6 +38,8 @@ struct vic {
 	struct clk *clk;
 	struct reset_control *rst;
 
+	bool can_use_context;
+
 	/* Platform configuration */
 	const struct vic_config *config;
 };
@@ -229,28 +231,38 @@ static int vic_load_firmware(struct vic *vic)
 {
 	struct host1x_client *client = &vic->client.base;
 	struct tegra_drm *tegra = vic->client.drm;
+	static DEFINE_MUTEX(lock);
+	u32 fce_bin_data_offset;
 	dma_addr_t iova;
 	size_t size;
 	void *virt;
 	int err;
 
-	if (vic->falcon.firmware.virt)
-		return 0;
+	mutex_lock(&lock);
+
+	if (vic->falcon.firmware.virt) {
+		err = 0;
+		goto unlock;
+	}
 
 	err = falcon_read_firmware(&vic->falcon, vic->config->firmware);
 	if (err < 0)
-		return err;
+		goto unlock;
 
 	size = vic->falcon.firmware.size;
 
 	if (!client->group) {
 		virt = dma_alloc_coherent(vic->dev, size, &iova, GFP_KERNEL);
-		if (!virt)
-			return -ENOMEM;
+		if (!virt) {
+			err = -ENOMEM;
+			goto unlock;
+		}
 	} else {
 		virt = tegra_drm_alloc(tegra, size, &iova);
-		if (IS_ERR(virt))
-			return PTR_ERR(virt);
+		if (IS_ERR(virt)) {
+			err = PTR_ERR(virt);
+			goto unlock;
+		}
 	}
 
 	vic->falcon.firmware.virt = virt;
@@ -277,7 +289,28 @@ static int vic_load_firmware(struct vic *vic)
 		vic->falcon.firmware.phys = phys;
 	}
 
-	return 0;
+	/*
+	 * Check if firmware is new enough to not require mapping firmware
+	 * to data buffer domains.
+	 */
+	fce_bin_data_offset = *(u32 *)(virt + VIC_UCODE_FCE_DATA_OFFSET);
+
+	if (!vic->config->supports_sid) {
+		vic->can_use_context = false;
+	} else if (fce_bin_data_offset != 0x0 && fce_bin_data_offset != 0xa5a5a5a5) {
+		/*
+		 * Firmware will access FCE through STREAMID0, so context
+		 * isolation cannot be used.
+		 */
+		vic->can_use_context = false;
+		dev_warn_once(vic->dev, "context isolation disabled due to old firmware\n");
+	} else {
+		vic->can_use_context = true;
+	}
+
+unlock:
+	mutex_unlock(&lock);
+	return err;
 
 cleanup:
 	if (!client->group)
@@ -285,6 +318,7 @@ static int vic_load_firmware(struct vic *vic)
 	else
 		tegra_drm_free(tegra, size, virt, iova);
 
+	mutex_unlock(&lock);
 	return err;
 }
 
@@ -358,10 +392,28 @@ static void vic_close_channel(struct tegra_drm_context *context)
 	host1x_channel_put(context->channel);
 }
 
+static int vic_get_streamid_offset(struct tegra_drm_client *client, u32 *offset)
+{
+	struct vic *vic = to_vic(client);
+	int err;
+
+	/* This doesn't access HW so it's safe to call without powering up. */
+	err = vic_load_firmware(vic);
+	if (err < 0)
+		return err;
+
+	if (!vic->can_use_context)
+		return -EOPNOTSUPP;
+
+	*offset = 0x30;
+	return 0;
+}
+
 static const struct tegra_drm_client_ops vic_ops = {
 	.open_channel = vic_open_channel,
 	.close_channel = vic_close_channel,
 	.submit = tegra_drm_submit,
+	.get_streamid_offset = vic_get_streamid_offset,
 };
 
 #define NVIDIA_TEGRA_124_VIC_FIRMWARE "nvidia/tegra124/vic03_ucode.bin"
-- 
2.35.0