linux-kernel - [PATCH] drm/bridge: dw-hdmi: handle ELD when DRM_BRIDGE_ATTACH_NO

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-Id: <20211029135947.3022875-1-narmstrong@baylibre.com>
Date:   Fri, 29 Oct 2021 15:59:47 +0200
From:   Neil Armstrong <narmstrong@...libre.com>
To:     a.hajda@...sung.com, Laurent.pinchart@...asonboard.com,
        robert.foss@...aro.org, jonas@...boo.se, jernej.skrabec@...il.com
Cc:     daniel@...ll.ch, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org,
        Neil Armstrong <narmstrong@...libre.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>
Subject: [PATCH] drm/bridge: dw-hdmi: handle ELD when DRM_BRIDGE_ATTACH_NO_CONNECTOR

The current ELD handling takes the internal connector ELD buffer and
shares it to the I2S and AHB sub-driver.

But with DRM_BRIDGE_ATTACH_NO_CONNECTOR, the connector is created
elsewhere (not not), and an eventual connector is known only
if the bridge chain up to a connector is enabled.

The current dw-hdmi code gets the current connector from
atomic_enable() so use the already stored connector pointer and
replace the buffer pointer with a callback returning the current
connector ELD buffer.

Since a connector is not always available, either pass an empty
ELD to the alsa HDMI driver or don't call snd_pcm_hw_constraint_eld()
in AHB driver.

Reported-by: Martin Blumenstingl <martin.blumenstingl@...glemail.com>
Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
---
 drivers/gpu/drm/bridge/synopsys/dw-hdmi-ahb-audio.c | 10 +++++++---
 drivers/gpu/drm/bridge/synopsys/dw-hdmi-audio.h     |  4 ++--
 drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c |  9 ++++++++-
 drivers/gpu/drm/bridge/synopsys/dw-hdmi.c           | 12 ++++++++++--
 4 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-ahb-audio.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-ahb-audio.c
index d0db1acf11d7..7d2ed0ed2fe2 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-ahb-audio.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-ahb-audio.c
@@ -320,13 +320,17 @@ static int dw_hdmi_open(struct snd_pcm_substream *substream)
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct snd_dw_hdmi *dw = substream->private_data;
 	void __iomem *base = dw->data.base;
+	u8 *eld;
 	int ret;
 
 	runtime->hw = dw_hdmi_hw;
 
-	ret = snd_pcm_hw_constraint_eld(runtime, dw->data.eld);
-	if (ret < 0)
-		return ret;
+	eld = dw->data.get_eld(dw->data.hdmi);
+	if (eld) {
+		ret = snd_pcm_hw_constraint_eld(runtime, eld);
+		if (ret < 0)
+			return ret;
+	}
 
 	ret = snd_pcm_limit_hw_rates(runtime);
 	if (ret < 0)
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-audio.h b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-audio.h
index cb07dc0da5a7..f72d27208ebe 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-audio.h
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-audio.h
@@ -9,15 +9,15 @@ struct dw_hdmi_audio_data {
 	void __iomem *base;
 	int irq;
 	struct dw_hdmi *hdmi;
-	u8 *eld;
+	u8 *(*get_eld)(struct dw_hdmi *hdmi);
 };
 
 struct dw_hdmi_i2s_audio_data {
 	struct dw_hdmi *hdmi;
-	u8 *eld;
 
 	void (*write)(struct dw_hdmi *hdmi, u8 val, int offset);
 	u8 (*read)(struct dw_hdmi *hdmi, int offset);
+	u8 *(*get_eld)(struct dw_hdmi *hdmi);
 };
 
 #endif
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c
index feb04f127b55..f50b47ac11a8 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c
@@ -135,8 +135,15 @@ static int dw_hdmi_i2s_get_eld(struct device *dev, void *data, uint8_t *buf,
 			       size_t len)
 {
 	struct dw_hdmi_i2s_audio_data *audio = data;
+	u8 *eld;
+
+	eld = audio->get_eld(audio->hdmi);
+	if (eld)
+		memcpy(buf, eld, min_t(size_t, MAX_ELD_BYTES, len));
+	else
+		/* Pass en empty ELD if connector not available */
+		memset(buf, 0, len);
 
-	memcpy(buf, audio->eld, min_t(size_t, MAX_ELD_BYTES, len));
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index 62ae63565d3a..54d8fdad395f 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -757,6 +757,14 @@ static void hdmi_enable_audio_clk(struct dw_hdmi *hdmi, bool enable)
 	hdmi_writeb(hdmi, hdmi->mc_clkdis, HDMI_MC_CLKDIS);
 }
 
+static u8 *hdmi_audio_get_eld(struct dw_hdmi *hdmi)
+{
+	if (!hdmi->curr_conn)
+		return NULL;
+
+	return hdmi->curr_conn->eld;
+}
+
 static void dw_hdmi_ahb_audio_enable(struct dw_hdmi *hdmi)
 {
 	hdmi_set_cts_n(hdmi, hdmi->audio_cts, hdmi->audio_n);
@@ -3432,7 +3440,7 @@ struct dw_hdmi *dw_hdmi_probe(struct platform_device *pdev,
 		audio.base = hdmi->regs;
 		audio.irq = irq;
 		audio.hdmi = hdmi;
-		audio.eld = hdmi->connector.eld;
+		audio.get_eld = hdmi_audio_get_eld;
 		hdmi->enable_audio = dw_hdmi_ahb_audio_enable;
 		hdmi->disable_audio = dw_hdmi_ahb_audio_disable;
 
@@ -3445,7 +3453,7 @@ struct dw_hdmi *dw_hdmi_probe(struct platform_device *pdev,
 		struct dw_hdmi_i2s_audio_data audio;
 
 		audio.hdmi	= hdmi;
-		audio.eld	= hdmi->connector.eld;
+		audio.get_eld	= hdmi_audio_get_eld;
 		audio.write	= hdmi_writeb;
 		audio.read	= hdmi_readb;
 		hdmi->enable_audio = dw_hdmi_i2s_audio_enable;
-- 
2.25.1