[PATCH 1/2] slimbus: stream: handle unsupported bitrates for presence rate

[PATCH 1/2] slimbus: stream: handle unsupported bitrates for presence rate

[Krzysztof Kozlowski]

Handle errors of getting presence rate for unsupported stream bitrate,
instead of sending -EINVAL in change content message.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 drivers/slimbus/stream.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/slimbus/stream.c b/drivers/slimbus/stream.c
index f8eade1e0132..28fbecb3907d 100644
--- a/drivers/slimbus/stream.c
+++ b/drivers/slimbus/stream.c
@@ -204,7 +204,7 @@ int slim_stream_prepare(struct slim_stream_runtime *rt,
 {
 	struct slim_controller *ctrl = rt->dev->ctrl;
 	struct slim_port *port;
-	int num_ports, i, port_id;
+	int num_ports, i, port_id, prrate;
 
 	pr_err("%s:%d AAAA\n", __func__, __LINE__);
 	if (rt->ports) {
@@ -222,6 +222,13 @@ int slim_stream_prepare(struct slim_stream_runtime *rt,
 	rt->bps = cfg->bps;
 	rt->direction = cfg->direction;
 
+	prrate = slim_get_prate_code(cfg->rate);
+	if (prrate < 0) {
+		dev_err(&rt->dev->dev, "Cannot get presence rate for rate %d Hz\n",
+			cfg->rate);
+		return -EINVAL;
+	}
+
 	if (cfg->rate % ctrl->a_framer->superfreq) {
 		/*
 		 * data rate not exactly multiple of super frame,
@@ -242,7 +249,7 @@ int slim_stream_prepare(struct slim_stream_runtime *rt,
 		port = &rt->ports[i];
 		port->state = SLIM_PORT_DISCONNECTED;
 		port->id = port_id;
-		port->ch.prrate = slim_get_prate_code(cfg->rate);
+		port->ch.prrate = prrate;
 		port->ch.id = cfg->chs[i];
 		port->ch.data_fmt = SLIM_CH_DATA_FMT_NOT_DEFINED;
 		port->ch.aux_fmt = SLIM_CH_AUX_FMT_NOT_APPLICABLE;
-- 
2.34.1

[PATCH 2/2] slimbus: qcom-ngd-ctrl: add support for 44.1 Khz frequency

[Krzysztof Kozlowski]

Add support for 44.1Khz frequency by dynamically calculating the slimbus
parameters instead of statically defining them.

Co-developed-by: Prudhvi Yarlagadda <pyarlaga@codeaurora.org>
Signed-off-by: Prudhvi Yarlagadda <pyarlaga@codeaurora.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 drivers/slimbus/qcom-ngd-ctrl.c | 64 ++++++++++++++++++++++++++++++---
 1 file changed, 59 insertions(+), 5 deletions(-)

diff --git a/drivers/slimbus/qcom-ngd-ctrl.c b/drivers/slimbus/qcom-ngd-ctrl.c
index ac84fdc2822f..051ac5cba207 100644
--- a/drivers/slimbus/qcom-ngd-ctrl.c
+++ b/drivers/slimbus/qcom-ngd-ctrl.c
@@ -944,6 +944,54 @@ static int qcom_slim_ngd_xfer_msg_sync(struct slim_controller *ctrl,
 	return ret;
 }
 
+static int qcom_slim_calc_coef(struct slim_stream_runtime *rt, int *exp)
+{
+	struct slim_controller *ctrl = rt->dev->ctrl;
+	int coef;
+
+	if (rt->ratem * ctrl->a_framer->superfreq < rt->rate)
+		rt->ratem++;
+
+	coef = rt->ratem;
+	*exp = 0;
+
+	/*
+	 * CRM = Cx(2^E) is the formula we are using.
+	 * Here C is the coffecient and E is the exponent.
+	 * CRM is the Channel Rate Multiplier.
+	 * Coefficeint should be either 1 or 3 and exponenet
+	 * should be an integer between 0 to 9, inclusive.
+	 */
+	while (1) {
+		while ((coef & 0x1) != 0x1) {
+			coef >>= 1;
+			*exp = *exp + 1;
+		}
+
+		if (coef <= 3)
+			break;
+
+		coef++;
+	}
+
+	/*
+	 * we rely on the coef value (1 or 3) to set a bit
+	 * in the slimbus message packet. This bit is
+	 * BIT(5) which is the segment rate coefficient.
+	 */
+	if (coef == 1) {
+		if (*exp > 9)
+			return -EIO;
+		coef = 0;
+	} else {
+		if (*exp > 8)
+			return -EIO;
+		coef = 1;
+	}
+
+	return coef;
+}
+
 static int qcom_slim_ngd_enable_stream(struct slim_stream_runtime *rt)
 {
 	struct slim_device *sdev = rt->dev;
@@ -967,16 +1015,22 @@ static int qcom_slim_ngd_enable_stream(struct slim_stream_runtime *rt)
 		struct slim_port *port = &rt->ports[i];
 
 		if (txn.msg->num_bytes == 0) {
-			int seg_interval = SLIM_SLOTS_PER_SUPERFRAME/rt->ratem;
-			int exp;
+			int exp = 0, coef = 0;
 
 			wbuf[txn.msg->num_bytes++] = sdev->laddr;
 			wbuf[txn.msg->num_bytes] = rt->bps >> 2 |
 						   (port->ch.aux_fmt << 6);
 
-			/* Data channel segment interval not multiple of 3 */
-			exp = seg_interval % 3;
-			if (exp)
+			/* calculate coef dynamically */
+			coef = qcom_slim_calc_coef(rt, &exp);
+			if (coef < 0) {
+				dev_err(&sdev->dev,
+				"%s: error calculating coef %d\n", __func__,
+									coef);
+				return -EIO;
+			}
+
+			if (coef)
 				wbuf[txn.msg->num_bytes] |= BIT(5);
 
 			txn.msg->num_bytes++;
-- 
2.34.1

Re: [PATCH 1/2] slimbus: stream: handle unsupported bitrates for presence rate

[Krzysztof Kozlowski]

On 30/09/2022 11:20, Krzysztof Kozlowski wrote:
> Handle errors of getting presence rate for unsupported stream bitrate,
> instead of sending -EINVAL in change content message.
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> ---
>  drivers/slimbus/stream.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/slimbus/stream.c b/drivers/slimbus/stream.c
> index f8eade1e0132..28fbecb3907d 100644
> --- a/drivers/slimbus/stream.c
> +++ b/drivers/slimbus/stream.c
> @@ -204,7 +204,7 @@ int slim_stream_prepare(struct slim_stream_runtime *rt,
>  {
>  	struct slim_controller *ctrl = rt->dev->ctrl;
>  	struct slim_port *port;
> -	int num_ports, i, port_id;
> +	int num_ports, i, port_id, prrate;
>  
>  	pr_err("%s:%d AAAA\n", __func__, __LINE__);

The context is from development tree. I'll rebase and send a v2.


Best regards,
Krzysztof