From 989d8a7c2927b83648f4e698c87c0ad7c4cea24d Mon Sep 17 00:00:00 2001 From: Florent Kermarrec Date: Tue, 26 May 2015 07:37:09 +0200 Subject: [PATCH] liteata: fix spelling & mistakes in doc --- .../doc/source/docs/frontend/index.rst | 58 ++++++++++--------- 1 file changed, 30 insertions(+), 28 deletions(-) diff --git a/misoclib/mem/litesata/doc/source/docs/frontend/index.rst b/misoclib/mem/litesata/doc/source/docs/frontend/index.rst index a7bf09e7d..21b03f0ce 100644 --- a/misoclib/mem/litesata/doc/source/docs/frontend/index.rst +++ b/misoclib/mem/litesata/doc/source/docs/frontend/index.rst @@ -15,13 +15,13 @@ Packets and user commands/responses are described in the next sections. Packets description =================== -Sink and Source are packets with additional parameters. A packet has the following signals: +Sink and Source endpoints use packets with additional parameters. A packet has the following signals: - - :code:`stb`: Strobe signal indicates that command or data is valid. - - :code:`sop`: Start Of Packet signal indicates that current command or data is the first of the packet. - - :code:`eop`: End Of Packet signal indicates that current command or data is the last of the packet. - - :code:`ack`: Response from the endpoint indicates that core is able to accept our command or data. - - :code:`data`: Current data of the packet. + - :code:`stb`: Strobe signal, indicates that command or data is valid. + - :code:`sop`: Start Of Packet signal, indicates that current command or data is the first of the packet. + - :code:`eop`: End Of Packet signal, indicates that current command or data is the last of the packet. + - :code:`ack`: Acknowledge signal, indicates the destination is able to accept current data. + - :code:`data`: Data signal. .. figure:: packets.png :width: 50% @@ -31,20 +31,20 @@ Sink and Source are packets with additional parameters. A packet has the followi .. tip:: - - When a packet only has a command or :code:`data`, :code:`sop` and :code:`eop` must be set to 1 on the same clock cycle. + - When a packet only has a :code:`data`, :code:`sop` and :code:`eop` must be set to 1 on the same clock cycle. - A :code:`data` is accepted when :code:`stb` =1 and :code:`ack` =1. User Commands ============= -All transfers are initiated using the Sink endpoint which has the following signals: +All transfers are initiated using the Sink endpoint of the interface which has the following signals: - - :code:`write`: 1 bit signal indicates if we want to write data to the HDD. - - :code:`read`: 1 bit signal indicaties if we want to read data from the HDD. - - :code:`identify`: 1 bit signal indicates if command is an identify device command (use to get HDD informations). - - :code:`sector`: 48 bits signal, the sector number we are going to write or read. - - :code:`count`: 16 bits signal, the number of sectors we are going to write or read. - - :code:`data`: n x 32 bits signal, the write data. (n depends of the frontend module) + - :code:`write`: 1 bit signal, indicates a write command. + - :code:`read`: 1 bit signal, indicaties a aread command. + - :code:`identify`: 1 bit signal, indicates an identify command. (used to get HDD informations). + - :code:`sector`: 48 bits signal, sector number for the write or read. + - :code:`count`: 16 bits signal, number of sectors for the write or read. + - :code:`data`: n x 32 bits signal, write data. (n depends of the frontend module) .. tip:: @@ -57,12 +57,12 @@ User Responses Responses are obtained from the Source endpoint which has the following signals: - - :code:`write`: 1 bit signal indicates if command was a write. - - :code:`read`: 1 bit signal indicaties if command was a read. - - :code:`identify`: 1 bit signal indicates if command was an identify device command. - - :code:`last`: 1 bit signal indicates if this is the last packet of the response. (A response can be return in several packets) - - :code:`failed`: 1 bit signal identicates if an error was detected in the response (CRC, FIS...) - - :code:`data`: n x 32 bits signal, the read data. (n depends of the frontend module) + - :code:`write`: 1 bit signal, indicates a write response. + - :code:`read`: 1 bit signal, indicaties a read response. + - :code:`identify`: 1 bit signal, indicates an identify response. + - :code:`last`: 1 bit signal, indicates it's the last packet of the response. (A response can be return in several packets) + - :code:`failed`: 1 bit signal, indicates that an error was detected in the response (CRC, FIS...) + - :code:`data`: n x 32 bits signal, read data. (n depends of the frontend module) .. tip:: @@ -77,12 +77,12 @@ Frontend modules LiteSATA provides a configurable and flexible frontend that can be used to: - Provides any number of user ports. -- Generate any RAID configuration when used with multiple HDDs. +- Generate RAID configurations when used with multiple HDDs. Crossbar ======== -The crossbar let the user request any number of ports. It automatically arbitrate requests and dispatch responses to the corresponding ports. +The crossbar allows the user to request any number of ports for its application. It automatically arbitrates requests and dispatches responses to the corresponding ports. The following example creates a crossbar and 2 user ports: @@ -95,7 +95,7 @@ The following example creates a crossbar and 2 user ports: Striping ======== -The striping module segment data so that data is stored on N different controllers. (RAID0 equivalent) +The striping module segments data so that data is stored on N different controllers. (RAID0 equivalent) .. code-block:: python @@ -115,7 +115,7 @@ The following example creates a striping with 2 HDDs: self.submodules.sata_striping = LiteSATAStriping([self.sata_core0, self.sata_core1]) -:code:`sata_striping`'s sink and source are the user interface. +:code:`sata_striping`'s Sink and Source are the user interface. Mirroring ========= @@ -139,7 +139,7 @@ Writes are mirrored on each controller: portX (stalled) +----> controllerX | portX (stalled) +-----> controllerX portN (stalled) +----> controllerN | portN ----------+-----> controllerN -Writes have priority on reads. When a write is presented on one of the port, the module waits for all ongoing reads to finish and commute to write mode. Once all writes are serviced it returns to read mode. +Writes have priority on reads. When a write is presented on one of the ports, the module waits for all ongoing reads to finish and commute to write mode. Once all writes are serviced it returns to read mode. Characteristics: - :code:`port`'s visible capacity = :code:`controller`'s visible capacity @@ -148,11 +148,13 @@ Characteristics: It can be used for data redundancy and/or to increase total reads speed. +The following example creates a mirroring with 2 HDDs: + .. code-block:: python self.submodules.sata_mirroring = LiteSATAMirroring([self.sata_core0, self.sata_core1]) -:code:`sata_striping`'s ports[0] and ports[1] are the user interfaces. +:code:`sata_striping`'s :code:`ports[0]` and :code:`ports[1]` are the user interfaces. Modules combinations ==================== @@ -180,9 +182,9 @@ Since it's probably easier to figure out how to use the frontend modules with re - A BIST_ (Data generator and checker) design that can be used to understand how to connect your logic to the user_port provided by the crossbar. -- A Striping_ design that can be used to understand how to connect couple 4 HDDs together in striping mode and do a BIST it. +- A Striping_ design that can be used to understand how to combine 4 HDDs together in striping mode and do a BIST on it. -- A Mirroring_ design that can be used to understand how to connect couple 4 HDDs together in Mirroring mode and do a BIST it. +- A Mirroring_ design that can be used to understand how to combine 4 HDDs together in mirroring mode and do a BIST on it. .. _BIST: https://github.com/m-labs/misoc/blob/master/misoclib/mem/litesata/example_designs/targets/bist.py