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[3/9] tty: n_gsm: add missing description to gsm_config

Message ID 20230405054730.3850-3-daniel.starke@siemens.com
State Superseded
Headers show
Series None | expand

Commit Message

D. Starke April 5, 2023, 5:47 a.m. UTC 
From: Daniel Starke <daniel.starke@siemens.com>

Currently, all available structure fields in gsmmux.h except those
for gsm_config are commented.

Fix this by adding appropriate comments to the not commented fields.

Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
---
 include/uapi/linux/gsmmux.h | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

Comments

D. Starke April 6, 2023, 5:26 a.m. UTC | #1 
> > +	unsigned int mru;	/* Maximum incoming frame payload size */
> > +	unsigned int mtu;	/* Maximum outgoing frame payload size */
> 
> I'm used to "payload" referring in networking context to "useful" part of 
> the frame but MTU/MRU probably includes headers too? Maybe just say
> "frame size"?

Just frame size is incorrect, as the basic/advanced option mode header and
byte stuffing do not count against this number. See 'gsm0_receive' and
'gsm1_receive' and also ch. 5.7.2 of the standard. The outgoing limit is
applied in 'gsm_dlci_data_output' and 'gsm_dlci_data_output_framed'.

Link: https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1516

Best regards,
Daniel Starke
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Patch

diff --git a/include/uapi/linux/gsmmux.h b/include/uapi/linux/gsmmux.h
index 33ee7b857c52..422a52e184b3 100644
--- a/include/uapi/linux/gsmmux.h
+++ b/include/uapi/linux/gsmmux.h
@@ -8,17 +8,17 @@ 
 
 struct gsm_config
 {
-	unsigned int adaption;
-	unsigned int encapsulation;
-	unsigned int initiator;
-	unsigned int t1;
-	unsigned int t2;
-	unsigned int t3;
-	unsigned int n2;
-	unsigned int mru;
-	unsigned int mtu;
-	unsigned int k;
-	unsigned int i;
+	unsigned int adaption;	/* Convergence layer type */
+	unsigned int encapsulation; /* Framing (0 = basic option, 1 = advanced option) */
+	unsigned int initiator;	/* Initiator or responder */
+	unsigned int t1;	/* Acknowledgment timer */
+	unsigned int t2;	/* Response timer for multiplexer control channel */
+	unsigned int t3;	/* Response timer for wake-up procedure */
+	unsigned int n2;	/* Maximum number of retransmissions */
+	unsigned int mru;	/* Maximum incoming frame payload size */
+	unsigned int mtu;	/* Maximum outgoing frame payload size */
+	unsigned int k;		/* Window size */
+	unsigned int i;		/* Frame type (1 = UIH, 2 = UI) */
 	unsigned int unused[8];	/* Can not be used */
 };