From 32c01266c0aab060550f592b3fe59405be8ab022 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Thu, 30 Apr 2020 18:04:14 +0200 Subject: [PATCH] docs: networking: convert PLIP.txt to ReST - add SPDX header; - mark code blocks and literals as such; - adjust identation, whitespaces and blank lines where needed; - add to networking/index.rst. Signed-off-by: Mauro Carvalho Chehab Signed-off-by: David S. Miller --- Documentation/networking/index.rst | 1 + .../networking/{PLIP.txt => plip.rst} | 43 +++++++++++-------- drivers/net/plip/Kconfig | 2 +- 3 files changed, 27 insertions(+), 19 deletions(-) rename Documentation/networking/{PLIP.txt => plip.rst} (92%) diff --git a/Documentation/networking/index.rst b/Documentation/networking/index.rst index 696181a96e3c..18bb10239cad 100644 --- a/Documentation/networking/index.rst +++ b/Documentation/networking/index.rst @@ -92,6 +92,7 @@ Contents: packet_mmap phonet pktgen + plip .. only:: subproject and html diff --git a/Documentation/networking/PLIP.txt b/Documentation/networking/plip.rst similarity index 92% rename from Documentation/networking/PLIP.txt rename to Documentation/networking/plip.rst index ad7e3f7c3bbf..0eda745050ff 100644 --- a/Documentation/networking/PLIP.txt +++ b/Documentation/networking/plip.rst @@ -1,4 +1,8 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================================================ PLIP: The Parallel Line Internet Protocol Device +================================================ Donald Becker (becker@super.org) I.D.A. Supercomputing Research Center, Bowie MD 20715 @@ -83,7 +87,7 @@ When the PLIP driver is used in IRQ mode, the timeout used for triggering a data transfer (the maximal time the PLIP driver would allow the other side before announcing a timeout, when trying to handshake a transfer of some data) is, by default, 500usec. As IRQ delivery is more or less immediate, -this timeout is quite sufficient. +this timeout is quite sufficient. When in IRQ-less mode, the PLIP driver polls the parallel port HZ times per second (where HZ is typically 100 on most platforms, and 1024 on an @@ -115,7 +119,7 @@ printer "null" cable to transfer data four bits at a time using data bit outputs connected to status bit inputs. The second data transfer method relies on both machines having -bi-directional parallel ports, rather than output-only ``printer'' +bi-directional parallel ports, rather than output-only ``printer`` ports. This allows byte-wide transfers and avoids reconstructing nibbles into bytes, leading to much faster transfers. @@ -132,7 +136,7 @@ bits with standard status register implementation. A cable that implements this protocol is available commercially as a "Null Printer" or "Turbo Laplink" cable. It can be constructed with -two DB-25 male connectors symmetrically connected as follows: +two DB-25 male connectors symmetrically connected as follows:: STROBE output 1* D0->ERROR 2 - 15 15 - 2 @@ -146,7 +150,8 @@ two DB-25 male connectors symmetrically connected as follows: SLCTIN 17 - 17 extra grounds are 18*,19*,20*,21*,22*,23*,24* GROUND 25 - 25 -* Do not connect these pins on either end + + * Do not connect these pins on either end If the cable you are using has a metallic shield it should be connected to the metallic DB-25 shell at one end only. @@ -155,14 +160,14 @@ Parallel Transfer Mode 1 ======================== The second data transfer method relies on both machines having -bi-directional parallel ports, rather than output-only ``printer'' +bi-directional parallel ports, rather than output-only ``printer`` ports. This allows byte-wide transfers, and avoids reconstructing nibbles into bytes. This cable should not be used on unidirectional -``printer'' (as opposed to ``parallel'') ports or when the machine +``printer`` (as opposed to ``parallel``) ports or when the machine isn't configured for PLIP, as it will result in output driver conflicts and the (unlikely) possibility of damage. -The cable for this transfer mode should be constructed as follows: +The cable for this transfer mode should be constructed as follows:: STROBE->BUSY 1 - 11 D0->D0 2 - 2 @@ -179,7 +184,8 @@ The cable for this transfer mode should be constructed as follows: GND->ERROR 18 - 15 extra grounds are 19*,20*,21*,22*,23*,24* GROUND 25 - 25 -* Do not connect these pins on either end + + * Do not connect these pins on either end Once again, if the cable you are using has a metallic shield it should be connected to the metallic DB-25 shell at one end only. @@ -188,7 +194,7 @@ PLIP Mode 0 transfer protocol ============================= The PLIP driver is compatible with the "Crynwr" parallel port transfer -standard in Mode 0. That standard specifies the following protocol: +standard in Mode 0. That standard specifies the following protocol:: send header nibble '0x8' count-low octet @@ -196,20 +202,21 @@ standard in Mode 0. That standard specifies the following protocol: ... data octets checksum octet -Each octet is sent as +Each octet is sent as:: + >4)&0x0F)> To start a transfer the transmitting machine outputs a nibble 0x08. That raises the ACK line, triggering an interrupt in the receiving machine. The receiving machine disables interrupts and raises its own ACK -line. +line. -Restated: +Restated:: -(OUT is bit 0-4, OUT.j is bit j from OUT. IN likewise) -Send_Byte: - OUT := low nibble, OUT.4 := 1 - WAIT FOR IN.4 = 1 - OUT := high nibble, OUT.4 := 0 - WAIT FOR IN.4 = 0 + (OUT is bit 0-4, OUT.j is bit j from OUT. IN likewise) + Send_Byte: + OUT := low nibble, OUT.4 := 1 + WAIT FOR IN.4 = 1 + OUT := high nibble, OUT.4 := 0 + WAIT FOR IN.4 = 0 diff --git a/drivers/net/plip/Kconfig b/drivers/net/plip/Kconfig index b41035be2d51..e03556d1d0c2 100644 --- a/drivers/net/plip/Kconfig +++ b/drivers/net/plip/Kconfig @@ -21,7 +21,7 @@ config PLIP bits at a time (mode 0) or with special PLIP cables, to be used on bidirectional parallel ports only, which can transmit 8 bits at a time (mode 1); you can find the wiring of these cables in - . The cables can be up to + . The cables can be up to 15m long. Mode 0 works also if one of the machines runs DOS/Windows and has some PLIP software installed, e.g. the Crynwr PLIP packet driver ()