source: trunk/kernel/kern/chdev.h

Last change on this file was 683, checked in by alain, 9 months ago

All modifications required to support the <tcp_chat> application
including error recovery in case of packet loss.A

File size: 15.6 KB
Line 
1/*
2 * chdev.h - channel device (chdev) descriptor and API definition.
3 *
4 * Authors  Alain Greiner    (2016,2017,2018,2019,2020)
5 *
6 * Copyright (c) UPMC Sorbonne Universites
7 *
8 * This file is part of ALMOS-MKH
9 *
10 * ALMOS-MKH is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; version 2.0 of the License.
13 *
14 * ALMOS-MKH is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
21 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24#ifndef _CHDEV_H_
25#define _CHDEV_H_
26
27#include <kernel_config.h>
28#include <hal_kernel_types.h>
29#include <xlist.h>
30#include <remote_busylock.h>
31#include <dev_iob.h>
32#include <dev_ioc.h>
33#include <dev_nic.h>
34#include <dev_pic.h>
35#include <dev_fbf.h>
36#include <dev_txt.h>
37
38/****************************************************************************************
39 *       Channel Device descriptor definition
40 *
41 * This file defines the kernel representation of a generic (i.e. implementation
42 * independant) Channel Device descriptor (in brief "chdev").
43 * ALMOS-MKH supports multi-channels peripherals, and defines one separated chdev
44 * descriptor for each channel (and for each RX/TX direction for NIC and TXT devices).
45 * Each chdev contains a trans-clusters waiting queue, registering the "client threads",
46 * and an associated "server thread", handling these requests.
47 * These descriptors are physically distributed on all clusters to minimize contention.
48 * Therefore a given I/O operation involve generally three clusters:
49 * - the client cluster, containing the client thread,
50 * - the server cluster, containing the chdev and the server thread,
51 * - the I/O cluster, containing the physical device.
52 ***************************************************************************************/
53
54/****  Forward declarations  ****/
55
56struct  chdev_s;
57struct  thread_s;
58struct  boot_info_s;
59
60/****************************************************************************************
61 * These macros extract functionality and  implementation from the peripheral type.
62 ***************************************************************************************/
63 
64#define FUNC_FROM_TYPE( type )    ((uint32_t)(type>>16))
65#define IMPL_FROM_TYPE( type )    ((uint32_t)(type & 0x0000FFFF))
66
67/****************************************************************************************
68 * This defines the generic prototypes for the functions that must be defined
69 * by all drivers implementing a generic device:
70 * - "cmd"     : start a blocking I/O operation.
71 * - "isr"     : complete an I/O operation.
72 * - "aux"     : not for all drivers (implement special functions)
73 * The "cmd", "isr", and "aux" driver functions are registered in the generic chdev
74 * descriptor at kernel init, and are called to start and complete an I/O operation. 
75***************************************************************************************/
76
77typedef void (dev_ini_t) ( xptr_t dev );     
78typedef void (dev_cmd_t) ( xptr_t thread ); 
79typedef void (dev_isr_t) ( struct chdev_s * dev ); 
80typedef void (dev_aux_t) ( void * args ); 
81
82/****************************************************************************************
83 * This enum defines the supported generic device types.
84 * These types are functionnal types: all (architecture specific) implementations
85 * provide the same set of operations and the same driver API.
86 * This enum must be consistent with the enum in files arch_info.h, and arch_class.py.
87 *
88 * WARNING : The ICU device exist in boot_info to specify the base address of the
89 *           distributed LAPIC controler, but it does not exist as a chdev in the kernel,
90 *           as it is hidden in the driver associated to the PIC device.
91 ***************************************************************************************/
92 
93enum dev_func_type
94{
95        DEV_FUNC_RAM   =  0,
96        DEV_FUNC_ROM   =  1,
97        DEV_FUNC_FBF   =  2,
98    DEV_FUNC_IOB   =  3,
99    DEV_FUNC_IOC   =  4,
100        DEV_FUNC_MMC   =  5,
101        DEV_FUNC_DMA   =  6,
102        DEV_FUNC_NIC   =  7,
103        DEV_FUNC_TIM   =  8,
104        DEV_FUNC_TXT   =  9,
105    DEV_FUNC_ICU   = 10,   
106    DEV_FUNC_PIC   = 11,
107
108    DEV_FUNC_NR    = 12,
109};
110
111/******************************************************************************************
112 * This structure defines a chdev (channel device) descriptor.
113 * This structure is NOT replicated, and can be located in any cluster.
114 * One server thread is in charge of handling the commands registered in the queue
115 * of clients associated to each chdev descriptor.
116 *
117 * For each device type ***, the specific extension is defined in the "dev_***.h" file.
118 *
119 * NOTE . For most chdevs, the busylock is used to protect the waiting queue changes,
120 *        when a client registers in this queue, or is removed after service.
121 *      . This busylock is also used to protect direct access to the shared
122 *        kernel TXT0 terminal, that does not use the waiting queue.
123 *      . For most chdevs, the client waiting queue is a list of threads, but it is
124 *        a list of sockets for the NIC chdevs. It is unused for ICU, PIC, and IOB.
125 *****************************************************************************************/
126
127typedef struct chdev_s
128{
129        uint32_t             func;        /*! peripheral functionnal type                    */
130        uint32_t             impl;        /*! peripheral implementation type                 */
131    uint32_t             channel;     /*! channel index                                  */
132    bool_t               is_rx;       /*! relevant for NIC and TXT peripherals           */
133        xptr_t               base;        /*! extended pointer on channel device segment     */
134    char                 name[16];    /*! name (required by DEVFS)                       */
135
136    dev_cmd_t          * cmd;         /*! local pointer on driver CMD function           */
137    dev_isr_t          * isr;         /*! local pointer on driver ISR function           */
138    dev_aux_t          * aux;         /*! local pointer on driver AUX function           */
139
140    struct thread_s    * server;      /*! local pointer on associated server thread      */
141
142    uint32_t             irq_type;    /*! associated IRQ type in local ICU               */
143    uint32_t             irq_id;      /*! associated IRQ index in local ICU              */
144
145        xlist_entry_t        wait_root;   /*! root of clients waiting queue                  */
146    remote_busylock_t    wait_lock;   /*! lock protecting waiting queue                  */
147    uint32_t             wait_nr;     /*! number of registered clients (NIC only)        */
148
149    union
150    {
151        iob_extend_t     iob;         /*! IOB specific extension                         */
152        ioc_extend_t     ioc;         /*! IOC specific extension                         */
153        nic_extend_t     nic;         /*! NIC specific extension                         */
154        pic_extend_t     pic;         /*! PIC specific extension                         */
155        fbf_extend_t     fbf;         /*! FBF specific extension                         */
156        txt_extend_t     txt;         /*! TXT specific extension                         */
157    } 
158    ext;
159}
160chdev_t;
161
162/******************************************************************************************
163 * This structure defines the channel_devices descriptors directory.
164 * Each entry in this structure contains an extended pointer on a chdev descriptor.
165 * There is one entry per channel OR per cluster, depending on peripheral type.
166 * This structure is replicated in each cluster, and is initialised during kernel init.
167 * It is used for fast access to a device descriptor, from type and channel for an
168 * external peripheral, or from type and cluster for an internal peripheral.
169 * - a "shared" chdev can be accessed by any thread running in any cluster.
170 * - a "private" chdev can only be accessed by a thread running in local cluster.
171 *****************************************************************************************/
172
173typedef struct chdev_directory_s
174{
175    xptr_t   iob;                                // external / single channel / shared
176    xptr_t   pic;                                // external / single channel / shared
177
178    xptr_t   ioc[CONFIG_MAX_IOC_CHANNELS];       // external / multi-channels / shared
179    xptr_t   fbf[CONFIG_MAX_FBF_CHANNELS];       // external / multi-channels / shared
180    xptr_t   txt_rx[CONFIG_MAX_TXT_CHANNELS];    // external / multi-channels / shared
181    xptr_t   txt_tx[CONFIG_MAX_TXT_CHANNELS];    // external / multi-channels / shared
182    xptr_t   nic_rx[CONFIG_MAX_NIC_CHANNELS];    // external / multi-channels / shared
183    xptr_t   nic_tx[CONFIG_MAX_NIC_CHANNELS];    // external / multi-channels / shared
184
185    xptr_t   mmc[CONFIG_MAX_CLUSTERS];           // internal / single channel / shared
186
187    xptr_t   dma[CONFIG_MAX_DMA_CHANNELS];       // internal / multi-channels / private
188}
189chdev_directory_t;
190
191/****************************************************************************************
192 * This function returns a printable string for a device functionnal types.
193 ****************************************************************************************
194 * @ func_type  : functionnal type.
195 * @ return pointer on string.
196 ***************************************************************************************/
197char * chdev_func_str( uint32_t func_type );
198
199/****************************************************************************************
200 * This  function allocates memory and initializes a chdev descriptor in local cluster,
201 * from arguments values.  It should be called by a local thread.
202 * The device specific fields are initialised later.
203 ****************************************************************************************
204 * @ func      : functionnal type.
205 * @ impl      : implementation type.
206 * @ channel   : channel index / for multi-channels peripherals.
207 * @ is_rx     : for NIC peripheral / NIC RX if true / NIC TX if false.
208 * @ base      : extended pointer on peripheral segment base.
209 * @ return a local pointer on created chdev / return NULL if failure.
210 ***************************************************************************************/
211chdev_t * chdev_create( uint32_t    func,
212                        uint32_t    impl,
213                        uint32_t    channel,
214                        bool_t      is_rx,
215                        xptr_t      base );
216
217/****************************************************************************************
218 * This generic function is executed by an user thread requesting an IOC or TXT chdev
219 * service. It registers the calling thread in the waiting queue of a the remote
220 * chdev descriptor identified by the <chdev_xp> argument.
221 * It activates (i.e. unblocks) the server thread associated to chdev, blocks itself,
222 * and deschedule.  It is supposed to be re-activated by the server thread.
223 * It can be called by a thread running in any cluster.
224 * It cannot be used for a NIC or FBF chdev, because it is only convenient for one shot
225 * I/O operations, as the server thread removes the client thread from the waiting
226 * queue when it starts to execute the command.
227 ****************************************************************************************
228 * Implementation Note:
229 * The following actions are executed in a critical section, thanks to the
230 * busylock_acquire / busylock_release mechanism :
231 * 1) it takes the lock protecting the waiting queue.
232 * 2) it registers client thread in the server queue.
233 * 3) it unblocks the server thread from the THREAD_BLOCKED_CLIENT condition.
234 * 4) it blocks the client thread on the THREAD_BLOCKED_IO condition.
235 * 5) it send an IPI to the core running the server thread to force scheduling.
236 * 6) it releases the lock protecting waiting queue.
237 * 7) it deschedules.
238 ****************************************************************************************
239 * @ chdev_xp  : extended pointer on remote chdev descriptor.
240 ***************************************************************************************/
241void chdev_register_command( xptr_t chdev_xp );
242
243/****************************************************************************************
244 * This generic function is executed by the server thread associated to an IOC or TXT
245 * chdev identified by the <chdev> argument, to execute all commands registered in the
246 * waiting queue attached to this chev.
247 * When the clients queue is empty, the server thread blocks on the THREAD_BLOCKED_CLIENT
248 * condition and deschedules. It is supposed to be re-activated by a client thread
249 * registering a new command.
250 * It cannot be used for a NIC or FBF chdev, because it is only convenient for one shot
251 * I/O operations, as the server thread removes the client thread from the waiting
252 * queue when it starts to execute the command.
253 ****************************************************************************************
254 * Implementation Note:
255 * All driver CMD functions are supposed to be blocking, and return only when the command
256 * is completed. These functions can use either a busy waiting policy, or a descheduling
257 * policy, blocking on the THREAD_BLOCKED_ISR condition. In the descheduling scenario,
258 * the server thread is supposed to be reactivated by the ISR attached to the hardware
259 * interrupts signaling command completion.
260 ****************************************************************************************
261 * @ chdev   : local pointer on device descriptor.
262 ***************************************************************************************/
263void chdev_server_func( chdev_t * chdev );
264
265/****************************************************************************************
266 * This function returns an extended pointer on the chdev associated to a pseudo file
267 * descriptor (type FILE_TYPE_DEV) identified by the <file_xp> argument.
268 * It can be called by a thread running in any cluster.
269 * It enters kernel panic if the inode has not the expected type.
270 ****************************************************************************************
271 * @ file_xp   : extended pointer on the pseudo file descriptor.
272 * @ return an extended pointer on chdev.
273 ***************************************************************************************/
274xptr_t chdev_from_file( xptr_t file_xp );
275
276/****************************************************************************************
277 * This function display relevant values for a remote chdev descriptor.
278 ****************************************************************************************
279 * @ chdev_xp   : pointer on chdev.
280 ***************************************************************************************/
281void chdev_display( xptr_t chdev_xp );
282
283/****************************************************************************************
284 * This function displays the local copy of the external chdevs directory.
285 * (global variable replicated in all clusters)
286 ***************************************************************************************/
287void chdev_dir_display( void );
288
289/****************************************************************************************
290 * This function displays the list of threads registered in the queue associated
291 * to the chdev identified by the <chdev_xp>.
292 ****************************************************************************************
293 * # root_xp  : extended pointer
294 ***************************************************************************************/
295void chdev_queue_display( xptr_t chdev_xp );
296
297#endif  /* _CHDEV_H_ */
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