1 .. SPDX-License-Identifier: GPL-2.0+ 1 .. SPDX-License-Identifier: GPL-2.0+
2 2
3 ==================== 3 ====================
4 Xilinx SD-FEC Driver 4 Xilinx SD-FEC Driver
5 ==================== 5 ====================
6 6
7 Overview 7 Overview
8 ======== 8 ========
9 9
10 This driver supports SD-FEC Integrated Block f 10 This driver supports SD-FEC Integrated Block for Zynq |Ultrascale+ (TM)| RFSoCs.
11 11
12 .. |Ultrascale+ (TM)| unicode:: Ultrascale+ U+ 12 .. |Ultrascale+ (TM)| unicode:: Ultrascale+ U+2122
13 .. with trademark sign 13 .. with trademark sign
14 14
15 For a full description of SD-FEC core features 15 For a full description of SD-FEC core features, see the `SD-FEC Product Guide (PG256) <https://www.xilinx.com/cgi-bin/docs/ipdoc?c=sd_fec;v=latest;d=pg256-sdfec-integrated-block.pdf>`_
16 16
17 This driver supports the following features: 17 This driver supports the following features:
18 18
19 - Retrieval of the Integrated Block configur 19 - Retrieval of the Integrated Block configuration and status information
20 - Configuration of LDPC codes 20 - Configuration of LDPC codes
21 - Configuration of Turbo decoding 21 - Configuration of Turbo decoding
22 - Monitoring errors 22 - Monitoring errors
23 23
24 Missing features, known issues, and limitation 24 Missing features, known issues, and limitations of the SD-FEC driver are as
25 follows: 25 follows:
26 26
27 - Only allows a single open file handler to 27 - Only allows a single open file handler to any instance of the driver at any time
28 - Reset of the SD-FEC Integrated Block is no 28 - Reset of the SD-FEC Integrated Block is not controlled by this driver
29 - Does not support shared LDPC code table wr 29 - Does not support shared LDPC code table wraparound
30 30
31 The device tree entry is described in: 31 The device tree entry is described in:
32 `linux-xlnx/Documentation/devicetree/bindings/ 32 `linux-xlnx/Documentation/devicetree/bindings/misc/xlnx,sd-fec.yaml <https://github.com/Xilinx/linux-xlnx/blob/master/Documentation/devicetree/bindings/misc/xlnx%2Csd-fec.yaml>`_
33 33
34 34
35 Modes of Operation 35 Modes of Operation
36 ------------------ 36 ------------------
37 37
38 The driver works with the SD-FEC core in two m 38 The driver works with the SD-FEC core in two modes of operation:
39 39
40 - Run-time configuration 40 - Run-time configuration
41 - Programmable Logic (PL) initialization 41 - Programmable Logic (PL) initialization
42 42
43 43
44 Run-time Configuration 44 Run-time Configuration
45 ~~~~~~~~~~~~~~~~~~~~~~ 45 ~~~~~~~~~~~~~~~~~~~~~~
46 46
47 For Run-time configuration the role of driver 47 For Run-time configuration the role of driver is to allow the software application to do the following:
48 48
49 - Load the configuration parameters fo 49 - Load the configuration parameters for either Turbo decode or LDPC encode or decode
50 - Activate the SD-FEC core 50 - Activate the SD-FEC core
51 - Monitor the SD-FEC core for errors 51 - Monitor the SD-FEC core for errors
52 - Retrieve the status and configuratio 52 - Retrieve the status and configuration of the SD-FEC core
53 53
54 Programmable Logic (PL) Initialization 54 Programmable Logic (PL) Initialization
55 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 55 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
56 56
57 For PL initialization, supporting logic loads 57 For PL initialization, supporting logic loads configuration parameters for either
58 the Turbo decode or LDPC encode or decode. Th 58 the Turbo decode or LDPC encode or decode. The role of the driver is to allow
59 the software application to do the following: 59 the software application to do the following:
60 60
61 - Activate the SD-FEC core 61 - Activate the SD-FEC core
62 - Monitor the SD-FEC core for errors 62 - Monitor the SD-FEC core for errors
63 - Retrieve the status and configuratio 63 - Retrieve the status and configuration of the SD-FEC core
64 64
65 65
66 Driver Structure 66 Driver Structure
67 ================ 67 ================
68 68
69 The driver provides a platform device where th 69 The driver provides a platform device where the ``probe`` and ``remove``
70 operations are provided. 70 operations are provided.
71 71
72 - probe: Updates configuration register with 72 - probe: Updates configuration register with device-tree entries plus determines the current activate state of the core, for example, is the core bypassed or has the core been started.
73 73
74 74
75 The driver defines the following driver file o 75 The driver defines the following driver file operations to provide user
76 application interfaces: 76 application interfaces:
77 77
78 - open: Implements restriction that only a s 78 - open: Implements restriction that only a single file descriptor can be open per SD-FEC instance at any time
79 - release: Allows another file descriptor to 79 - release: Allows another file descriptor to be open, that is after current file descriptor is closed
80 - poll: Provides a method to monitor for SD- 80 - poll: Provides a method to monitor for SD-FEC Error events
81 - unlocked_ioctl: Provides the following ioc 81 - unlocked_ioctl: Provides the following ioctl commands that allows the application configure the SD-FEC core:
82 82
83 - :c:macro:`XSDFEC_START_DEV` 83 - :c:macro:`XSDFEC_START_DEV`
84 - :c:macro:`XSDFEC_STOP_DEV` 84 - :c:macro:`XSDFEC_STOP_DEV`
85 - :c:macro:`XSDFEC_GET_STATUS` 85 - :c:macro:`XSDFEC_GET_STATUS`
86 - :c:macro:`XSDFEC_SET_IRQ` 86 - :c:macro:`XSDFEC_SET_IRQ`
87 - :c:macro:`XSDFEC_SET_TURBO` 87 - :c:macro:`XSDFEC_SET_TURBO`
88 - :c:macro:`XSDFEC_ADD_LDPC_CO 88 - :c:macro:`XSDFEC_ADD_LDPC_CODE_PARAMS`
89 - :c:macro:`XSDFEC_GET_CONFIG` 89 - :c:macro:`XSDFEC_GET_CONFIG`
90 - :c:macro:`XSDFEC_SET_ORDER` 90 - :c:macro:`XSDFEC_SET_ORDER`
91 - :c:macro:`XSDFEC_SET_BYPASS` 91 - :c:macro:`XSDFEC_SET_BYPASS`
92 - :c:macro:`XSDFEC_IS_ACTIVE` 92 - :c:macro:`XSDFEC_IS_ACTIVE`
93 - :c:macro:`XSDFEC_CLEAR_STATS 93 - :c:macro:`XSDFEC_CLEAR_STATS`
94 - :c:macro:`XSDFEC_SET_DEFAULT 94 - :c:macro:`XSDFEC_SET_DEFAULT_CONFIG`
95 95
96 96
97 Driver Usage 97 Driver Usage
98 ============ 98 ============
99 99
100 100
101 Overview 101 Overview
102 -------- 102 --------
103 103
104 After opening the driver, the user should find 104 After opening the driver, the user should find out what operations need to be
105 performed to configure and activate the SD-FEC 105 performed to configure and activate the SD-FEC core and determine the
106 configuration of the driver. 106 configuration of the driver.
107 The following outlines the flow the user shoul 107 The following outlines the flow the user should perform:
108 108
109 - Determine Configuration 109 - Determine Configuration
110 - Set the order, if not already configured a 110 - Set the order, if not already configured as desired
111 - Set Turbo decode, LPDC encode or decode pa 111 - Set Turbo decode, LPDC encode or decode parameters, depending on how the
112 SD-FEC core is configured plus if the SD-F 112 SD-FEC core is configured plus if the SD-FEC has not been configured for PL
113 initialization 113 initialization
114 - Enable interrupts, if not already enabled 114 - Enable interrupts, if not already enabled
115 - Bypass the SD-FEC core, if required 115 - Bypass the SD-FEC core, if required
116 - Start the SD-FEC core if not already start 116 - Start the SD-FEC core if not already started
117 - Get the SD-FEC core status 117 - Get the SD-FEC core status
118 - Monitor for interrupts 118 - Monitor for interrupts
119 - Stop the SD-FEC core 119 - Stop the SD-FEC core
120 120
121 121
122 Note: When monitoring for interrupts if a crit 122 Note: When monitoring for interrupts if a critical error is detected where a reset is required, the driver will be required to load the default configuration.
123 123
124 124
125 Determine Configuration 125 Determine Configuration
126 ----------------------- 126 -----------------------
127 127
128 Determine the configuration of the SD-FEC core 128 Determine the configuration of the SD-FEC core by using the ioctl
129 :c:macro:`XSDFEC_GET_CONFIG`. 129 :c:macro:`XSDFEC_GET_CONFIG`.
130 130
131 Set the Order 131 Set the Order
132 ------------- 132 -------------
133 133
134 Setting the order determines how the order of 134 Setting the order determines how the order of Blocks can change from input to output.
135 135
136 Setting the order is done by using the ioctl : 136 Setting the order is done by using the ioctl :c:macro:`XSDFEC_SET_ORDER`
137 137
138 Setting the order can only be done if the foll 138 Setting the order can only be done if the following restrictions are met:
139 139
140 - The ``state`` member of struct :c:ty 140 - The ``state`` member of struct :c:type:`xsdfec_status <xsdfec_status>` filled by the ioctl :c:macro:`XSDFEC_GET_STATUS` indicates the SD-FEC core has not STARTED
141 141
142 142
143 Add LDPC Codes 143 Add LDPC Codes
144 -------------- 144 --------------
145 145
146 The following steps indicate how to add LDPC c 146 The following steps indicate how to add LDPC codes to the SD-FEC core:
147 147
148 - Use the auto-generated parameters to 148 - Use the auto-generated parameters to fill the :c:type:`struct xsdfec_ldpc_params <xsdfec_ldpc_params>` for the desired LDPC code.
149 - Set the SC, QA, and LA table offsets 149 - Set the SC, QA, and LA table offsets for the LPDC parameters and the parameters in the structure :c:type:`struct xsdfec_ldpc_params <xsdfec_ldpc_params>`
150 - Set the desired Code Id value in the 150 - Set the desired Code Id value in the structure :c:type:`struct xsdfec_ldpc_params <xsdfec_ldpc_params>`
151 - Add the LPDC Code Parameters using t 151 - Add the LPDC Code Parameters using the ioctl :c:macro:`XSDFEC_ADD_LDPC_CODE_PARAMS`
152 - For the applied LPDC Code Parameter 152 - For the applied LPDC Code Parameter use the function :c:func:`xsdfec_calculate_shared_ldpc_table_entry_size` to calculate the size of shared LPDC code tables. This allows the user to determine the shared table usage so when selecting the table offsets for the next LDPC code parameters unused table areas can be selected.
153 - Repeat for each LDPC code parameter. 153 - Repeat for each LDPC code parameter.
154 154
155 Adding LDPC codes can only be done if the foll 155 Adding LDPC codes can only be done if the following restrictions are met:
156 156
157 - The ``code`` member of :c:type:`stru 157 - The ``code`` member of :c:type:`struct xsdfec_config <xsdfec_config>` filled by the ioctl :c:macro:`XSDFEC_GET_CONFIG` indicates the SD-FEC core is configured as LDPC
158 - The ``code_wr_protect`` of :c:type:` 158 - The ``code_wr_protect`` of :c:type:`struct xsdfec_config <xsdfec_config>` filled by the ioctl :c:macro:`XSDFEC_GET_CONFIG` indicates that write protection is not enabled
159 - The ``state`` member of struct :c:ty 159 - The ``state`` member of struct :c:type:`xsdfec_status <xsdfec_status>` filled by the ioctl :c:macro:`XSDFEC_GET_STATUS` indicates the SD-FEC core has not started
160 160
161 Set Turbo Decode 161 Set Turbo Decode
162 ---------------- 162 ----------------
163 163
164 Configuring the Turbo decode parameters is don 164 Configuring the Turbo decode parameters is done by using the ioctl :c:macro:`XSDFEC_SET_TURBO` using auto-generated parameters to fill the :c:type:`struct xsdfec_turbo <xsdfec_turbo>` for the desired Turbo code.
165 165
166 Adding Turbo decode can only be done if the fo 166 Adding Turbo decode can only be done if the following restrictions are met:
167 167
168 - The ``code`` member of :c:type:`stru 168 - The ``code`` member of :c:type:`struct xsdfec_config <xsdfec_config>` filled by the ioctl :c:macro:`XSDFEC_GET_CONFIG` indicates the SD-FEC core is configured as TURBO
169 - The ``state`` member of struct :c:ty 169 - The ``state`` member of struct :c:type:`xsdfec_status <xsdfec_status>` filled by the ioctl :c:macro:`XSDFEC_GET_STATUS` indicates the SD-FEC core has not STARTED
170 170
171 Enable Interrupts 171 Enable Interrupts
172 ----------------- 172 -----------------
173 173
174 Enabling or disabling interrupts is done by us 174 Enabling or disabling interrupts is done by using the ioctl :c:macro:`XSDFEC_SET_IRQ`. The members of the parameter passed, :c:type:`struct xsdfec_irq <xsdfec_irq>`, to the ioctl are used to set and clear different categories of interrupts. The category of interrupt is controlled as following:
175 175
176 - ``enable_isr`` controls the ``tlast`` inte 176 - ``enable_isr`` controls the ``tlast`` interrupts
177 - ``enable_ecc_isr`` controls the ECC interr 177 - ``enable_ecc_isr`` controls the ECC interrupts
178 178
179 If the ``code`` member of :c:type:`struct xsdf 179 If the ``code`` member of :c:type:`struct xsdfec_config <xsdfec_config>` filled by the ioctl :c:macro:`XSDFEC_GET_CONFIG` indicates the SD-FEC core is configured as TURBO then the enabling ECC errors is not required.
180 180
181 Bypass the SD-FEC 181 Bypass the SD-FEC
182 ----------------- 182 -----------------
183 183
184 Bypassing the SD-FEC is done by using the ioct 184 Bypassing the SD-FEC is done by using the ioctl :c:macro:`XSDFEC_SET_BYPASS`
185 185
186 Bypassing the SD-FEC can only be done if the f 186 Bypassing the SD-FEC can only be done if the following restrictions are met:
187 187
188 - The ``state`` member of :c:type:`str 188 - The ``state`` member of :c:type:`struct xsdfec_status <xsdfec_status>` filled by the ioctl :c:macro:`XSDFEC_GET_STATUS` indicates the SD-FEC core has not STARTED
189 189
190 Start the SD-FEC core 190 Start the SD-FEC core
191 --------------------- 191 ---------------------
192 192
193 Start the SD-FEC core by using the ioctl :c:ma 193 Start the SD-FEC core by using the ioctl :c:macro:`XSDFEC_START_DEV`
194 194
195 Get SD-FEC Status 195 Get SD-FEC Status
196 ----------------- 196 -----------------
197 197
198 Get the SD-FEC status of the device by using t 198 Get the SD-FEC status of the device by using the ioctl :c:macro:`XSDFEC_GET_STATUS`, which will fill the :c:type:`struct xsdfec_status <xsdfec_status>`
199 199
200 Monitor for Interrupts 200 Monitor for Interrupts
201 ---------------------- 201 ----------------------
202 202
203 - Use the poll system call to monitor 203 - Use the poll system call to monitor for an interrupt. The poll system call waits for an interrupt to wake it up or times out if no interrupt occurs.
204 - On return Poll ``revents`` will indi 204 - On return Poll ``revents`` will indicate whether stats and/or state have been updated
205 - ``POLLPRI`` indicates a crit 205 - ``POLLPRI`` indicates a critical error and the user should use :c:macro:`XSDFEC_GET_STATUS` and :c:macro:`XSDFEC_GET_STATS` to confirm
206 - ``POLLRDNORM`` indicates a n 206 - ``POLLRDNORM`` indicates a non-critical error has occurred and the user should use :c:macro:`XSDFEC_GET_STATS` to confirm
207 - Get stats by using the ioctl :c:macr 207 - Get stats by using the ioctl :c:macro:`XSDFEC_GET_STATS`
208 - For critical error the ``isr 208 - For critical error the ``isr_err_count`` or ``uecc_count`` member of :c:type:`struct xsdfec_stats <xsdfec_stats>` is non-zero
209 - For non-critical errors the 209 - For non-critical errors the ``cecc_count`` member of :c:type:`struct xsdfec_stats <xsdfec_stats>` is non-zero
210 - Get state by using the ioctl :c:macr 210 - Get state by using the ioctl :c:macro:`XSDFEC_GET_STATUS`
211 - For a critical error the ``s 211 - For a critical error the ``state`` of :c:type:`xsdfec_status <xsdfec_status>` will indicate a Reset Is Required
212 - Clear stats by using the ioctl :c:ma 212 - Clear stats by using the ioctl :c:macro:`XSDFEC_CLEAR_STATS`
213 213
214 If a critical error is detected where a reset 214 If a critical error is detected where a reset is required. The application is required to call the ioctl :c:macro:`XSDFEC_SET_DEFAULT_CONFIG`, after the reset and it is not required to call the ioctl :c:macro:`XSDFEC_STOP_DEV`
215 215
216 Note: Using poll system call prevents busy loo 216 Note: Using poll system call prevents busy looping using :c:macro:`XSDFEC_GET_STATS` and :c:macro:`XSDFEC_GET_STATUS`
217 217
218 Stop the SD-FEC Core 218 Stop the SD-FEC Core
219 --------------------- 219 ---------------------
220 220
221 Stop the device by using the ioctl :c:macro:`X 221 Stop the device by using the ioctl :c:macro:`XSDFEC_STOP_DEV`
222 222
223 Set the Default Configuration 223 Set the Default Configuration
224 ----------------------------- 224 -----------------------------
225 225
226 Load default configuration by using the ioctl 226 Load default configuration by using the ioctl :c:macro:`XSDFEC_SET_DEFAULT_CONFIG` to restore the driver.
227 227
228 Limitations 228 Limitations
229 ----------- 229 -----------
230 230
231 Users should not duplicate SD-FEC device file 231 Users should not duplicate SD-FEC device file handlers, for example fork() or dup() a process that has a created an SD-FEC file handler.
232 232
233 Driver IOCTLs 233 Driver IOCTLs
234 ============== 234 ==============
235 235
236 .. c:macro:: XSDFEC_START_DEV 236 .. c:macro:: XSDFEC_START_DEV
237 .. kernel-doc:: include/uapi/misc/xilinx_sdfec 237 .. kernel-doc:: include/uapi/misc/xilinx_sdfec.h
238 :doc: XSDFEC_START_DEV 238 :doc: XSDFEC_START_DEV
239 239
240 .. c:macro:: XSDFEC_STOP_DEV 240 .. c:macro:: XSDFEC_STOP_DEV
241 .. kernel-doc:: include/uapi/misc/xilinx_sdfec 241 .. kernel-doc:: include/uapi/misc/xilinx_sdfec.h
242 :doc: XSDFEC_STOP_DEV 242 :doc: XSDFEC_STOP_DEV
243 243
244 .. c:macro:: XSDFEC_GET_STATUS 244 .. c:macro:: XSDFEC_GET_STATUS
245 .. kernel-doc:: include/uapi/misc/xilinx_sdfec 245 .. kernel-doc:: include/uapi/misc/xilinx_sdfec.h
246 :doc: XSDFEC_GET_STATUS 246 :doc: XSDFEC_GET_STATUS
247 247
248 .. c:macro:: XSDFEC_SET_IRQ 248 .. c:macro:: XSDFEC_SET_IRQ
249 .. kernel-doc:: include/uapi/misc/xilinx_sdfec 249 .. kernel-doc:: include/uapi/misc/xilinx_sdfec.h
250 :doc: XSDFEC_SET_IRQ 250 :doc: XSDFEC_SET_IRQ
251 251
252 .. c:macro:: XSDFEC_SET_TURBO 252 .. c:macro:: XSDFEC_SET_TURBO
253 .. kernel-doc:: include/uapi/misc/xilinx_sdfec 253 .. kernel-doc:: include/uapi/misc/xilinx_sdfec.h
254 :doc: XSDFEC_SET_TURBO 254 :doc: XSDFEC_SET_TURBO
255 255
256 .. c:macro:: XSDFEC_ADD_LDPC_CODE_PARAMS 256 .. c:macro:: XSDFEC_ADD_LDPC_CODE_PARAMS
257 .. kernel-doc:: include/uapi/misc/xilinx_sdfec 257 .. kernel-doc:: include/uapi/misc/xilinx_sdfec.h
258 :doc: XSDFEC_ADD_LDPC_CODE_PARAMS 258 :doc: XSDFEC_ADD_LDPC_CODE_PARAMS
259 259
260 .. c:macro:: XSDFEC_GET_CONFIG 260 .. c:macro:: XSDFEC_GET_CONFIG
261 .. kernel-doc:: include/uapi/misc/xilinx_sdfec 261 .. kernel-doc:: include/uapi/misc/xilinx_sdfec.h
262 :doc: XSDFEC_GET_CONFIG 262 :doc: XSDFEC_GET_CONFIG
263 263
264 .. c:macro:: XSDFEC_SET_ORDER 264 .. c:macro:: XSDFEC_SET_ORDER
265 .. kernel-doc:: include/uapi/misc/xilinx_sdfec 265 .. kernel-doc:: include/uapi/misc/xilinx_sdfec.h
266 :doc: XSDFEC_SET_ORDER 266 :doc: XSDFEC_SET_ORDER
267 267
268 .. c:macro:: XSDFEC_SET_BYPASS 268 .. c:macro:: XSDFEC_SET_BYPASS
269 .. kernel-doc:: include/uapi/misc/xilinx_sdfec 269 .. kernel-doc:: include/uapi/misc/xilinx_sdfec.h
270 :doc: XSDFEC_SET_BYPASS 270 :doc: XSDFEC_SET_BYPASS
271 271
272 .. c:macro:: XSDFEC_IS_ACTIVE 272 .. c:macro:: XSDFEC_IS_ACTIVE
273 .. kernel-doc:: include/uapi/misc/xilinx_sdfec 273 .. kernel-doc:: include/uapi/misc/xilinx_sdfec.h
274 :doc: XSDFEC_IS_ACTIVE 274 :doc: XSDFEC_IS_ACTIVE
275 275
276 .. c:macro:: XSDFEC_CLEAR_STATS 276 .. c:macro:: XSDFEC_CLEAR_STATS
277 .. kernel-doc:: include/uapi/misc/xilinx_sdfec 277 .. kernel-doc:: include/uapi/misc/xilinx_sdfec.h
278 :doc: XSDFEC_CLEAR_STATS 278 :doc: XSDFEC_CLEAR_STATS
279 279
280 .. c:macro:: XSDFEC_GET_STATS 280 .. c:macro:: XSDFEC_GET_STATS
281 .. kernel-doc:: include/uapi/misc/xilinx_sdfec 281 .. kernel-doc:: include/uapi/misc/xilinx_sdfec.h
282 :doc: XSDFEC_GET_STATS 282 :doc: XSDFEC_GET_STATS
283 283
284 .. c:macro:: XSDFEC_SET_DEFAULT_CONFIG 284 .. c:macro:: XSDFEC_SET_DEFAULT_CONFIG
285 .. kernel-doc:: include/uapi/misc/xilinx_sdfec 285 .. kernel-doc:: include/uapi/misc/xilinx_sdfec.h
286 :doc: XSDFEC_SET_DEFAULT_CONFIG 286 :doc: XSDFEC_SET_DEFAULT_CONFIG
287 287
288 Driver Type Definitions 288 Driver Type Definitions
289 ======================= 289 =======================
290 290
291 .. kernel-doc:: include/uapi/misc/xilinx_sdfec 291 .. kernel-doc:: include/uapi/misc/xilinx_sdfec.h
292 :internal: 292 :internal:
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