Received-SPF: pass (google.com: domain of linux-kernel+bounces-187363-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
From: Pankaj Gupta <pankaj.gupta@nxp.com>
Date: Thu, 23 May 2024 16:19:32 +0530
Subject: [PATCH v2 1/5] Documentation/firmware: add imx/se to
 other_interfaces
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
Message-Id: <20240523-imx-se-if-v2-1-5a6fd189a539@nxp.com>
References: <20240523-imx-se-if-v2-0-5a6fd189a539@nxp.com>
In-Reply-To: <20240523-imx-se-if-v2-0-5a6fd189a539@nxp.com>
To: Jonathan Corbet <corbet@lwn.net>, Rob Herring <robh+dt@kernel.org>, 
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, 
 Conor Dooley <conor+dt@kernel.org>, Shawn Guo <shawnguo@kernel.org>, 
 Sascha Hauer <s.hauer@pengutronix.de>, 
 Pengutronix Kernel Team <kernel@pengutronix.de>, 
 Fabio Estevam <festevam@gmail.com>, Rob Herring <robh@kernel.org>, 
 Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, 
 devicetree@vger.kernel.org, imx@lists.linux.dev, 
 linux-arm-kernel@lists.infradead.org, Pankaj Gupta <pankaj.gupta@nxp.com>
Precedence: bulk
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0:
	=?utf-8?B?YzBUTlFUVkZUVGVjTDAwbS82UUtEcVp3N2Q4azhRNi9NUVVleEVnQURSNmpn?=
 =?utf-8?B?NzA2VGRuSno2cFpub1hZVjkvMHpqdnhXOTFGTHIyb2czWHNMUDJVNWNDZkZo?=
 =?utf-8?B?a3Ura2cyNEVVaE5FazRVT3EvMCtJQkExRnduR2lqd1JiUy82UEFNODBMZE5C?=
 =?utf-8?B?bVNnSFluUjZxbVV1SkpTTkxOakNrQk4xSER5REVrUE9RNDZqcTg2c1lMQmEy?=
 =?utf-8?B?STdLdjRCcjcyWDlUY3FrRmlpTy8zU2dqc2tmQVYrS2o3emx3NFVBRllOc3Vk?=
 =?utf-8?B?T2QvMFFicGlCYXBKWTZha2MyNlRNeHRTRHI3NGlLNkgxcXM3TGx6M0h2SXhZ?=
 =?utf-8?B?RnUzZ0VySCtJQlFQRFg3eEJ3d29FbnFxSjZ3SmtSSE1ER21GU2l5VkJkMUhB?=
 =?utf-8?B?YVBZMGVuWnAwQXJsKy90TGpWcTdvQ3lDek1TbHhndUZTZkE4aUJhZ3R6L2RT?=
 =?utf-8?B?R3M4aVA0aTI1V200VDBwWXpNQ2FDR0lIQWRPYjBLMVVZM0dwM294NEYxVERH?=
 =?utf-8?B?YjNIZ1gxcWp5VXROeEZZeFBGd3pBdzdrell4aVZwMXQxUWNqQUtTUERzanMw?=
 =?utf-8?B?d0JEdUpuR0tPQ2l1cXZqZU12a0puZTAxUG4xbys5NXFMM21QQnB2TW1zUlg3?=
 =?utf-8?B?a2RnREc5YTArVzFiNW11MGhNcjZEUE1lQldVRWpFd2o0eG9rcUorY3BuMG5z?=
 =?utf-8?B?aTFzaDF1R3FuT2JWWW55dGJXdE9xS25ySHdmWGNyQTgrbzh0TDZHTmh2VE5H?=
 =?utf-8?B?V0tKSm5Kdm9ETFpoZjl1NW15dnU2NnB4b2dzd25qZTkzUm1kTjQ5U29JQ3NO?=
 =?utf-8?B?NndYQnlvemF4VW9EcVhWZk9ETWdWZStsc21pYWNoSEFsWkwzdWVFRUZ5Mmg3?=
 =?utf-8?B?elpUNi8zZGdPdVBtbkQzZGZ6NEVpNWkyWEdVcE1RSnMzWUJ0cFdETmxPUFpp?=
 =?utf-8?B?V0p1bmU1QURGaUNHUE9RRXRpTWo4aXowOGRoNkVsLzVGYzlBdjlYRjRrQWF2?=
 =?utf-8?B?YkY5MXlLbTRwU2taVWtmZ25ENzI0MEllK3FJTGJyREdMc2RWVWVzVURCMUtE?=
 =?utf-8?B?R2hQRUQ3TXFIWFNUSExGR2EremszZTl5dkt2d0R3allNemh6b2xVY2tuY2Yw?=
 =?utf-8?B?RUkzbis1ODYzWERLRTdoUEU0ejFydU81S2VKeUVPWWZ1b21jOTVka1lIYlgr?=
 =?utf-8?B?REJhU0M0TTA5L2tUSU5JZStkRHpTenJkU1RMK2h2ZUoxejRGbUJMNEpDd242?=
 =?utf-8?B?Y25QQXBjVGttZTAyOE5FTVJLY2l4ZmVod3VTODRVTXkzV1JzZm5XUEJEejJu?=
 =?utf-8?B?bWlOZVVsd2thc0E1T2k3QW9uTmV2Y1k4Sk90MXRJbHk0YnNVbUNYS0ViaTNx?=
 =?utf-8?B?N1NsT2dGVTVPSXdBQllrdkROTGpkYUgrUVFWMjI3Y1ZxWWJ5QldkTVBEUHQr?=
 =?utf-8?B?dUJDKzhqTHMxZkRRU1phTXA5bjBta3llMHVOV0U0NEhuS3NpQkY5UWlDcndF?=
 =?utf-8?B?SVEvNjVZempmUUNLT2RBZmdxYVJOYnJ4TzBSdTYxcEp4QmJ2OXdab1M3YjJK?=
 =?utf-8?B?OU8xYVFjemZuSDNpaWdtZXBjYTlxMFlZbGJmM1ZFa21JMHNBc2pqZjV3YytB?=
 =?utf-8?B?cXFhZE14NTdIMGpILzNUakJnQXZNL0Z5c0twanZNVDJUa1BGcW5ERjlwdk95?=
 =?utf-8?B?T1h6ZWxWcDFDaVNvdDBMZlZCRmdYdzA0RG1NaWZCOUFlQ1BkOTQ1SFhkYVo1?=
 =?utf-8?B?a2VJc1dDZFprY2NsSjlmMlp4aThaV1BxWmZHdWtLSEhLdHE4VkY5b0t6VDBi?=
 =?utf-8?B?bjFHLzdYb3NiWkt6MjFPMFVycTdYOVZETEdTQUF3QVV5QlpwQ2ZWLzJYVXVt?=
 =?utf-8?B?ajczVk11R2Y4bHNqQTJkM2xrVm1CTUxKZ0gySVZlSVpHZzVINHJnTGI1TWhZ?=
 =?utf-8?B?bC9rY0VCZ2pLOUtnT3dra1dOdXJPa052MzkwZnRWRlNXV3hlTXM0MDZEb2xC?=
 =?utf-8?B?UlY0ZXZqSHIyUlJXbjRKaEJjSGg3WnozaFNDZGlPOWRySWRXcDYrUE5nY1dn?=
 =?utf-8?B?NWZYbFZFSDQ0bk5DUExHV21QMGZNTCtBMm42djMzYnN4N0tQZlZRREtLL1FD?=
 =?utf-8?Q?tTq37OuFSl/0BGjHoiFU1VNZW?=
X-OriginatorOrg: nxp.com
X-MS-Exchange-CrossTenant-Network-Message-Id: aacb6be4-5423-460b-f759-08dc7b1671dd
X-MS-Exchange-CrossTenant-AuthSource: AM9PR04MB8604.eurprd04.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 23 May 2024 10:52:31.0942
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: o/4C4jPFwYm1GaRW03p6oMvjuZDh1yAy8RTnPcJXXdZLkggIEuCoYSgc5jYeW7ukbh+f1UWYMIQOvNde91bRKA==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM8PR04MB7474

Documents i.MX SoC's Service layer and C_DEV driver for selected SoC(s)
that contains the NXP hardware IP(s) for secure-enclaves(se) like:
- NXP EdgeLock Enclave on i.MX93 & i.MX8ULP

Signed-off-by: Pankaj Gupta <pankaj.gupta@nxp.com>
---
 .../driver-api/firmware/other_interfaces.rst       | 119 +++++++++++++++++++++
 1 file changed, 119 insertions(+)

diff --git a/Documentation/driver-api/firmware/other_interfaces.rst b/Documentation/driver-api/firmware/other_interfaces.rst
index 06ac89adaafb..65e69396e22a 100644
--- a/Documentation/driver-api/firmware/other_interfaces.rst
+++ b/Documentation/driver-api/firmware/other_interfaces.rst
@@ -49,3 +49,122 @@ of the requests on to a secure monitor (EL3).
 
 .. kernel-doc:: drivers/firmware/stratix10-svc.c
    :export:
+
+NXP Secure Enclave Firmware Interface
+=====================================
+
+Introduction
+------------
+The NXP's i.MX HW IP like EdgeLock-Enclave, V2X etc., creates an embedded secure
+enclave within the SoC boundary to enable features like
+ - Hardware Security Module (HSM)
+ - Security Hardware Extension (SHE)
+ - Vehicular to Anything (V2X)
+
+Each of the above feature, is enabled through dedicated NXP H/W IP on the SoC.
+On a single SoC, multiple hardware IP (or can say more than one secure enclave)
+can exists.
+
+NXP SoCs enabled with the such secure enclaves(SEs) IPs are:
+i.MX93, i.MX8ULP
+
+To communicate with one or more co-existing SE(s) on SoC, there is/are dedicated
+messaging units(MU) per SE. Each co-existing 'se' can have one or multiple exclusive
+MU(s), dedicated to itself. None of the MU is shared between two SEs.
+Communication of the MU is realized using the Linux mailbox driver.
+
+NXP Secure Enclave(SE) Interface
+--------------------------------
+All those SE interfaces 'se-if' that is/are dedicated to a particular SE, will be
+enumerated and provisioned under the very single 'SE' node.
+
+Each 'se-if', comprise of twp layers:
+- (C_DEV Layer) User-Space software-access interface.
+- (Service Layer) OS-level software-access interface.
+
+   +--------------------------------------------+
+   |            Character Device(C_DEV)         |
+   |                                            |
+   |   +---------+ +---------+     +---------+  |
+   |   | misc #1 | | misc #2 | ... | misc #n |  |
+   |   |  dev    | |  dev    |     | dev     |  |
+   |   +---------+ +---------+     +---------+  |
+   |        +-------------------------+         |
+   |        | Misc. Dev Synchr. Logic |         |
+   |        +-------------------------+         |
+   |                                            |
+   +--------------------------------------------+
+
+   +--------------------------------------------+
+   |               Service Layer                |
+   |                                            |
+   |      +-----------------------------+       |
+   |      | Message Serialization Logic |       |
+   |      +-----------------------------+       |
+   |          +---------------+                 |
+   |          |  imx-mailbox  |                 |
+   |          |   mailbox.c   |                 |
+   |          +---------------+                 |
+   |                                            |
+   +--------------------------------------------+
+
+- service layer:
+  This layer is responsible for ensuring the communication protocol, that is defined
+  for communication with firmware.
+
+  FW Communication protocol ensures two things:
+  - Serializing the messages to be sent over an MU.
+
+  - FW can handle one command-message at a time.
+
+- c_dev:
+  This layer offers character device contexts, created as '/dev/<se>_mux_chx'.
+  Using these multiple device contexts, that are getting multiplexed over a single MU,
+  user-space application(s) can call fops like write/read to send the command-message,
+  and read back the command-response-message to/from Firmware.
+  fops like read & write uses the above defined service layer API(s) to communicate with
+  Firmware.
+
+  Misc-device(/dev/<se>_mux_chn) synchronization protocol:
+
+                                Non-Secure               +   Secure
+                                                         |
+                                                         |
+                  +---------+      +-------------+       |
+                  | se_fw.c +<---->+imx-mailbox.c|       |
+                  |         |      |  mailbox.c  +<-->+------+    +------+
+                  +---+-----+      +-------------+    | MU X +<-->+ ELE |
+                      |                               +------+    +------+
+                      +----------------+                 |
+                      |                |                 |
+                      v                v                 |
+                  logical           logical              |
+                  receiver          waiter               |
+                     +                 +                 |
+                     |                 |                 |
+                     |                 |                 |
+                     |            +----+------+          |
+                     |            |           |          |
+                     |            |           |          |
+              device_ctx     device_ctx     device_ctx   |
+                                                         |
+                User 0        User 1       User Y        |
+                +------+      +------+     +------+      |
+                |misc.c|      |misc.c|     |misc.c|      |
+ kernel space   +------+      +------+     +------+      |
+                                                         |
+ +------------------------------------------------------ |
+                    |             |           |          |
+ userspace     /dev/ele_muXch0    |           |          |
+                          /dev/ele_muXch1     |          |
+                                        /dev/ele_muXchY  |
+                                                         |
+
+When a user sends a command to the firmware, it registers its device_ctx
+as waiter of a response from firmware.
+
+Enclave's Firmware owns the storage management, over linux filesystem.
+For this c_dev provisions a dedicated slave device called "receiver".
+
+.. kernel-doc:: drivers/firmware/imx/se_fw.c
+   :export:

-- 
2.34.1