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From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date: Mon, 03 Jun 2024 02:24:56 +0300
Subject: [PATCH RFC 3/7] usb: typec: ucsi: split read operation
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Message-Id: <20240603-ucsi-rework-interface-v1-3-99a6d544cec8@linaro.org>
References: <20240603-ucsi-rework-interface-v1-0-99a6d544cec8@linaro.org>
In-Reply-To: <20240603-ucsi-rework-interface-v1-0-99a6d544cec8@linaro.org>
To: Heikki Krogerus <heikki.krogerus@linux.intel.com>, 
 Greg Kroah-Hartman <gregkh@linuxfoundation.org>, 
 Maxime Coquelin <mcoquelin.stm32@gmail.com>, 
 Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Nikita Travkin <nikita@trvn.ru>, 
 Neil Armstrong <neil.armstrong@linaro.org>, linux-usb@vger.kernel.org, 
 linux-kernel@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, 
 linux-arm-kernel@lists.infradead.org

The read operation is only used to read fixed data at fixed offsets
(UCSI_VERSION, UCSI_CCI, UCSI_MESSAGE_IN). In some cases drivers apply
offset-specific overrides. Split the read() operation into three
operations, read_version(), read_cci(), read_message_in().

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 drivers/usb/typec/ucsi/ucsi.c         | 20 ++++++------
 drivers/usb/typec/ucsi/ucsi.h         |  9 ++++--
 drivers/usb/typec/ucsi/ucsi_acpi.c    | 60 +++++++++++++++++++++++++++++------
 drivers/usb/typec/ucsi/ucsi_ccg.c     | 50 +++++++++++++++--------------
 drivers/usb/typec/ucsi/ucsi_glink.c   | 19 ++++++++++-
 drivers/usb/typec/ucsi/ucsi_stm32g0.c | 19 ++++++++++-
 6 files changed, 130 insertions(+), 47 deletions(-)

diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index f58908a76e1d..a3a29ea4e325 100644
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -46,7 +46,7 @@ static int ucsi_read_message_in(struct ucsi *ucsi, void *buf,
 	if (ucsi->version <= UCSI_VERSION_1_2)
 		buf_size = clamp(buf_size, 0, 16);
 
-	return ucsi->ops->read(ucsi, UCSI_MESSAGE_IN, buf, buf_size);
+	return ucsi->ops->read_message_in(ucsi, buf, buf_size);
 }
 
 static int ucsi_acknowledge(struct ucsi *ucsi, bool conn_ack)
@@ -130,7 +130,7 @@ static int ucsi_exec_command(struct ucsi *ucsi, u64 cmd)
 	if (ret)
 		return ret;
 
-	ret = ucsi->ops->read(ucsi, UCSI_CCI, &cci, sizeof(cci));
+	ret = ucsi->ops->read_cci(ucsi, &cci);
 	if (ret)
 		return ret;
 
@@ -1294,7 +1294,7 @@ static int ucsi_reset_ppm(struct ucsi *ucsi)
 
 	mutex_lock(&ucsi->ppm_lock);
 
-	ret = ucsi->ops->read(ucsi, UCSI_CCI, &cci, sizeof(cci));
+	ret = ucsi->ops->read_cci(ucsi, &cci);
 	if (ret < 0)
 		goto out;
 
@@ -1312,8 +1312,7 @@ static int ucsi_reset_ppm(struct ucsi *ucsi)
 
 		tmo = jiffies + msecs_to_jiffies(UCSI_TIMEOUT_MS);
 		do {
-			ret = ucsi->ops->read(ucsi, UCSI_CCI,
-					      &cci, sizeof(cci));
+			ret = ucsi->ops->read_cci(ucsi, &cci);
 			if (ret < 0)
 				goto out;
 			if (cci & UCSI_CCI_COMMAND_COMPLETE)
@@ -1342,7 +1341,7 @@ static int ucsi_reset_ppm(struct ucsi *ucsi)
 		/* Give the PPM time to process a reset before reading CCI */
 		msleep(20);
 
-		ret = ucsi->ops->read(ucsi, UCSI_CCI, &cci, sizeof(cci));
+		ret = ucsi->ops->read_cci(ucsi, &cci);
 		if (ret)
 			goto out;
 
@@ -1745,7 +1744,7 @@ static int ucsi_init(struct ucsi *ucsi)
 	ucsi->ntfy = ntfy;
 
 	mutex_lock(&ucsi->ppm_lock);
-	ret = ucsi->ops->read(ucsi, UCSI_CCI, &cci, sizeof(cci));
+	ret = ucsi->ops->read_cci(ucsi, &cci);
 	mutex_unlock(&ucsi->ppm_lock);
 	if (ret)
 		return ret;
@@ -1859,7 +1858,9 @@ struct ucsi *ucsi_create(struct device *dev, const struct ucsi_operations *ops)
 {
 	struct ucsi *ucsi;
 
-	if (!ops || !ops->read || !ops->sync_control || !ops->async_control)
+	if (!ops ||
+	    !ops->read_version || !ops->read_cci || !ops->read_message_in ||
+	    !ops->sync_control || !ops->async_control)
 		return ERR_PTR(-EINVAL);
 
 	ucsi = kzalloc(sizeof(*ucsi), GFP_KERNEL);
@@ -1895,8 +1896,7 @@ int ucsi_register(struct ucsi *ucsi)
 {
 	int ret;
 
-	ret = ucsi->ops->read(ucsi, UCSI_VERSION, &ucsi->version,
-			      sizeof(ucsi->version));
+	ret = ucsi->ops->read_version(ucsi, &ucsi->version);
 	if (ret)
 		return ret;
 
diff --git a/drivers/usb/typec/ucsi/ucsi.h b/drivers/usb/typec/ucsi/ucsi.h
index 94ea54d3d47d..f770e1070424 100644
--- a/drivers/usb/typec/ucsi/ucsi.h
+++ b/drivers/usb/typec/ucsi/ucsi.h
@@ -56,7 +56,9 @@ struct dentry;
 
 /**
  * struct ucsi_operations - UCSI I/O operations
- * @read: Read operation
+ * @read_version: Read implemented UCSI version
+ * @read_cci: Read CCI register
+ * @read_message_in: Read message data from UCSI
  * @sync_control: Blocking control operation
  * @async_control: Non-blocking control operation
  * @update_altmodes: Squashes duplicate DP altmodes
@@ -68,8 +70,9 @@ struct dentry;
  * return immediately after sending the data to the PPM.
  */
 struct ucsi_operations {
-	int (*read)(struct ucsi *ucsi, unsigned int offset,
-		    void *val, size_t val_len);
+	int (*read_version)(struct ucsi *ucsi, u16 *version);
+	int (*read_cci)(struct ucsi *ucsi, u32 *cci);
+	int (*read_message_in)(struct ucsi *ucsi, void *val, size_t val_len);
 	int (*sync_control)(struct ucsi *ucsi, u64 command);
 	int (*async_control)(struct ucsi *ucsi, u64 command);
 	bool (*update_altmodes)(struct ucsi *ucsi, struct ucsi_altmode *orig,
diff --git a/drivers/usb/typec/ucsi/ucsi_acpi.c b/drivers/usb/typec/ucsi/ucsi_acpi.c
index feccbfc8acbe..61dd28dae3a4 100644
--- a/drivers/usb/typec/ucsi/ucsi_acpi.c
+++ b/drivers/usb/typec/ucsi/ucsi_acpi.c
@@ -45,8 +45,7 @@ static int ucsi_acpi_dsm(struct ucsi_acpi *ua, int func)
 	return 0;
 }
 
-static int ucsi_acpi_read(struct ucsi *ucsi, unsigned int offset,
-			  void *val, size_t val_len)
+static int ucsi_acpi_read_version(struct ucsi *ucsi, u16 *version)
 {
 	struct ucsi_acpi *ua = ucsi_get_drvdata(ucsi);
 	int ret;
@@ -55,7 +54,35 @@ static int ucsi_acpi_read(struct ucsi *ucsi, unsigned int offset,
 	if (ret)
 		return ret;
 
-	memcpy(val, ua->base + offset, val_len);
+	memcpy(version, ua->base + UCSI_VERSION, sizeof(*version));
+
+	return 0;
+}
+
+static int ucsi_acpi_read_cci(struct ucsi *ucsi, u32 *cci)
+{
+	struct ucsi_acpi *ua = ucsi_get_drvdata(ucsi);
+	int ret;
+
+	ret = ucsi_acpi_dsm(ua, UCSI_DSM_FUNC_READ);
+	if (ret)
+		return ret;
+
+	memcpy(cci, ua->base + UCSI_CCI, sizeof(*cci));
+
+	return 0;
+}
+
+static int ucsi_acpi_read_message_in(struct ucsi *ucsi, void *val, size_t val_len)
+{
+	struct ucsi_acpi *ua = ucsi_get_drvdata(ucsi);
+	int ret;
+
+	ret = ucsi_acpi_dsm(ua, UCSI_DSM_FUNC_READ);
+	if (ret)
+		return ret;
+
+	memcpy(val, ua->base + UCSI_MESSAGE_IN, val_len);
 
 	return 0;
 }
@@ -98,30 +125,45 @@ static int ucsi_acpi_sync_control(struct ucsi *ucsi, u64 command)
 }
 
 static const struct ucsi_operations ucsi_acpi_ops = {
-	.read = ucsi_acpi_read,
+	.read_version = ucsi_acpi_read_version,
+	.read_cci = ucsi_acpi_read_cci,
+	.read_message_in = ucsi_acpi_read_message_in,
 	.sync_control = ucsi_acpi_sync_control,
 	.async_control = ucsi_acpi_async_control
 };
 
 static int
-ucsi_zenbook_read(struct ucsi *ucsi, unsigned int offset, void *val, size_t val_len)
+ucsi_zenbook_read_cci(struct ucsi *ucsi, u32 *cci)
 {
 	struct ucsi_acpi *ua = ucsi_get_drvdata(ucsi);
 	int ret;
 
-	if (offset == UCSI_VERSION || UCSI_COMMAND(ua->cmd) == UCSI_PPM_RESET) {
+	if (UCSI_COMMAND(ua->cmd) == UCSI_PPM_RESET) {
 		ret = ucsi_acpi_dsm(ua, UCSI_DSM_FUNC_READ);
 		if (ret)
 			return ret;
 	}
 
-	memcpy(val, ua->base + offset, val_len);
+	memcpy(cci, ua->base + UCSI_CCI, sizeof(*cci));
+
+	return 0;
+}
+
+static int
+ucsi_zenbook_read_message_in(struct ucsi *ucsi, void *val, size_t val_len)
+{
+	struct ucsi_acpi *ua = ucsi_get_drvdata(ucsi);
+
+	/* UCSI_MESSAGE_IN is never read for PPM_RESET, return stored data */
+	memcpy(val, ua->base + UCSI_MESSAGE_IN, val_len);
 
 	return 0;
 }
 
 static const struct ucsi_operations ucsi_zenbook_ops = {
-	.read = ucsi_zenbook_read,
+	.read_version = ucsi_acpi_read_version,
+	.read_cci = ucsi_zenbook_read_cci,
+	.read_message_in = ucsi_zenbook_read_message_in,
 	.sync_control = ucsi_acpi_sync_control,
 	.async_control = ucsi_acpi_async_control
 };
@@ -143,7 +185,7 @@ static void ucsi_acpi_notify(acpi_handle handle, u32 event, void *data)
 	u32 cci;
 	int ret;
 
-	ret = ua->ucsi->ops->read(ua->ucsi, UCSI_CCI, &cci, sizeof(cci));
+	ret = ua->ucsi->ops->read_cci(ua->ucsi, &cci);
 	if (ret)
 		return;
 
diff --git a/drivers/usb/typec/ucsi/ucsi_ccg.c b/drivers/usb/typec/ucsi/ucsi_ccg.c
index 76b39bb9762d..6ccc394f268e 100644
--- a/drivers/usb/typec/ucsi/ucsi_ccg.c
+++ b/drivers/usb/typec/ucsi/ucsi_ccg.c
@@ -556,32 +556,34 @@ static void ucsi_ccg_nvidia_altmode(struct ucsi_ccg *uc,
 	}
 }
 
-static int ucsi_ccg_read(struct ucsi *ucsi, unsigned int offset,
-			 void *val, size_t val_len)
+static int ucsi_ccg_read_version(struct ucsi *ucsi, u16 *version)
 {
 	struct ucsi_ccg *uc = ucsi_get_drvdata(ucsi);
-	u16 reg = CCGX_RAB_UCSI_DATA_BLOCK(offset);
-	struct ucsi_capability *cap;
-	struct ucsi_altmode *alt;
-	int ret = 0;
+	u16 reg = CCGX_RAB_UCSI_DATA_BLOCK(UCSI_VERSION);
 
-	if (offset == UCSI_CCI) {
-		spin_lock(&uc->op_lock);
-		memcpy(val, &(uc->op_data).cci, val_len);
-		spin_unlock(&uc->op_lock);
-	} else if (offset == UCSI_MESSAGE_IN) {
-		spin_lock(&uc->op_lock);
-		memcpy(val, &(uc->op_data).message_in, val_len);
-		spin_unlock(&uc->op_lock);
-	} else {
-		ret = ccg_read(uc, reg, val, val_len);
-	}
+	return ccg_read(uc, reg, (u8 *)version, sizeof(*version));
+}
 
-	if (ret)
-		return ret;
+static int ucsi_ccg_read_cci(struct ucsi *ucsi, u32 *cci)
+{
+	struct ucsi_ccg *uc = ucsi_get_drvdata(ucsi);
 
-	if (offset != UCSI_MESSAGE_IN)
-		return ret;
+	spin_lock(&uc->op_lock);
+	*cci = uc->op_data.cci;
+	spin_unlock(&uc->op_lock);
+
+	return 0;
+}
+
+static int ucsi_ccg_read_message_in(struct ucsi *ucsi, void *val, size_t val_len)
+{
+	struct ucsi_ccg *uc = ucsi_get_drvdata(ucsi);
+	struct ucsi_capability *cap;
+	struct ucsi_altmode *alt;
+
+	spin_lock(&uc->op_lock);
+	memcpy(val, uc->op_data.message_in, val_len);
+	spin_unlock(&uc->op_lock);
 
 	switch (UCSI_COMMAND(uc->last_cmd_sent)) {
 	case UCSI_GET_CURRENT_CAM:
@@ -607,7 +609,7 @@ static int ucsi_ccg_read(struct ucsi *ucsi, unsigned int offset,
 	}
 	uc->last_cmd_sent = 0;
 
-	return ret;
+	return 0;
 }
 
 static int ucsi_ccg_async_control(struct ucsi *ucsi, u64 command)
@@ -663,7 +665,9 @@ static int ucsi_ccg_sync_control(struct ucsi *ucsi, u64 command)
 }
 
 static const struct ucsi_operations ucsi_ccg_ops = {
-	.read = ucsi_ccg_read,
+	.read_version = ucsi_ccg_read_version,
+	.read_cci = ucsi_ccg_read_cci,
+	.read_message_in = ucsi_ccg_read_message_in,
 	.sync_control = ucsi_ccg_sync_control,
 	.async_control = ucsi_ccg_async_control,
 	.update_altmodes = ucsi_ccg_update_altmodes
diff --git a/drivers/usb/typec/ucsi/ucsi_glink.c b/drivers/usb/typec/ucsi/ucsi_glink.c
index 047998f33274..7f6a48624ee5 100644
--- a/drivers/usb/typec/ucsi/ucsi_glink.c
+++ b/drivers/usb/typec/ucsi/ucsi_glink.c
@@ -114,6 +114,21 @@ static int pmic_glink_ucsi_read(struct ucsi *__ucsi, unsigned int offset,
 	return ret;
 }
 
+static int pmic_glink_ucsi_read_version(struct ucsi *ucsi, u16 *version)
+{
+	return pmic_glink_ucsi_read(ucsi, UCSI_VERSION, version, sizeof(*version));
+}
+
+static int pmic_glink_ucsi_read_cci(struct ucsi *ucsi, u32 *cci)
+{
+	return pmic_glink_ucsi_read(ucsi, UCSI_CCI, cci, sizeof(*cci));
+}
+
+static int pmic_glink_ucsi_read_message_in(struct ucsi *ucsi, void *val, size_t val_len)
+{
+	return pmic_glink_ucsi_read(ucsi, UCSI_MESSAGE_IN, val, val_len);
+}
+
 static int pmic_glink_ucsi_locked_write(struct pmic_glink_ucsi *ucsi, unsigned int offset,
 					const void *val, size_t val_len)
 {
@@ -214,7 +229,9 @@ static void pmic_glink_ucsi_connector_status(struct ucsi_connector *con)
 }
 
 static const struct ucsi_operations pmic_glink_ucsi_ops = {
-	.read = pmic_glink_ucsi_read,
+	.read_version = pmic_glink_ucsi_read_version,
+	.read_cci = pmic_glink_ucsi_read_cci,
+	.read_message_in = pmic_glink_ucsi_read_message_in,
 	.sync_control = pmic_glink_ucsi_sync_control,
 	.async_control = pmic_glink_ucsi_async_control,
 	.update_connector = pmic_glink_ucsi_update_connector,
diff --git a/drivers/usb/typec/ucsi/ucsi_stm32g0.c b/drivers/usb/typec/ucsi/ucsi_stm32g0.c
index f97dc5a075e2..e3cfcb258e43 100644
--- a/drivers/usb/typec/ucsi/ucsi_stm32g0.c
+++ b/drivers/usb/typec/ucsi/ucsi_stm32g0.c
@@ -359,6 +359,21 @@ static int ucsi_stm32g0_read(struct ucsi *ucsi, unsigned int offset, void *val,
 	return 0;
 }
 
+static int ucsi_stm32g0_read_version(struct ucsi *ucsi, u16 *version)
+{
+	return ucsi_stm32g0_read(ucsi, UCSI_VERSION, version, sizeof(*version));
+}
+
+static int ucsi_stm32g0_read_cci(struct ucsi *ucsi, u32 *cci)
+{
+	return ucsi_stm32g0_read(ucsi, UCSI_CCI, cci, sizeof(*cci));
+}
+
+static int ucsi_stm32g0_read_message_in(struct ucsi *ucsi, void *val, size_t len)
+{
+	return ucsi_stm32g0_read(ucsi, UCSI_MESSAGE_IN, val, len);
+}
+
 static int ucsi_stm32g0_async_control(struct ucsi *ucsi, u64 command)
 {
 	struct ucsi_stm32g0 *g0 = ucsi_get_drvdata(ucsi);
@@ -446,7 +461,9 @@ static irqreturn_t ucsi_stm32g0_irq_handler(int irq, void *data)
 }
 
 static const struct ucsi_operations ucsi_stm32g0_ops = {
-	.read = ucsi_stm32g0_read,
+	.read_version = ucsi_stm32g0_read_version,
+	.read_cci = ucsi_stm32g0_read_cci,
+	.read_message_in = ucsi_stm32g0_read_message_in,
 	.sync_control = ucsi_stm32g0_sync_control,
 	.async_control = ucsi_stm32g0_async_control,
 };

-- 
2.39.2