source: soft/giet_vm/giet_drivers/bdv_driver.c @ 400

Last change on this file since 400 was 357, checked in by alain, 10 years ago

cosmetic
File size: 14.7 KB
Line 
1///////////////////////////////////////////////////////////////////////////////////
2// File      : bdv_driver.c
3// Date      : 23/05/2013
4// Author    : alain greiner
5// Maintainer: cesar fuguet
6// Copyright (c) UPMC-LIP6
7///////////////////////////////////////////////////////////////////////////////////
8// The bdv_driver.c and bdv_driver.h files are part ot the GIET-VM kernel.
9// This driver supports the SocLib vci_block_device component, that is
10// a single channel, block oriented, external storage contrÃŽler.
11//
12// The _bdv_read() and _bdv_write() functions are always blocking.
13// They can be called in 3 modes:
14//
15// - In BOOT mode, these functions use a polling policy on the BDV STATUS
16//   register to detect transfer completion, as interrupts are not activated.
17//   This mode is used by the boot code to load the map.bin file into memory
18//   (before MMU activation), or to load the .elf files (after MMU activation).
19//
20// - In KERNEL mode, these functions use a descheduling strategy:
21//   The ISR executed when transfer completes should restart the calling task.
22//   There is no checking of user access right to the memory buffer.
23//   This mode must be used, for an "open" system call.
24//
25// - In USER mode, these functions use a descheduling strategy:
26//   The ISR executed when transfer completes should restart the calling task,
27//   The user access right to the memory buffer must be checked.
28//   This mode must be used for a "read/write" system call.
29//
30// As the BDV component can be used by several programs running in parallel,
31// the _bdv_lock variable guaranties exclusive access to the device.  The
32// _bdv_read() and _bdv_write() functions use atomic LL/SC to get the lock.
33//
34// Finally, the memory buffer must fulfill the following conditions:
35// - The buffer must be word aligned,
36// - The buffer must be mapped in user space for an user access,
37// - The buffer must be writable in case of (to_mem) access,
38// - The total number of physical pages occupied by the user buffer cannot
39//   be larger than 512 pages if the IOMMU is activated,
40// - All physical pages occupied by the user buffer must be contiguous
41//   if the IOMMU is not activated.
42// An error code is returned if these conditions are not verified.
43//
44// The SEG_IOC_BASE address must be defined in the hard_config.h file.
45///////////////////////////////////////////////////////////////////////////////////
46// Implementation notes:
47//
48// 1. In order to share code, the two _bdv_read() and _bdv_write() functions
49//    call the same _bdv_access() function.
50//
51// 2. All accesses to BDV registers are done by the two
52//    _bdv_set_register() and _bdv_get_register() low-level functions,
53//    that are handling virtual / physical extended addressing.
54///////////////////////////////////////////////////////////////////////////////////
55
56#include <giet_config.h>
57#include <hard_config.h>
58#include <bdv_driver.h>
59#include <xcu_driver.h>
60#include <ioc_driver.h>
61#include <utils.h>
62#include <tty_driver.h>
63#include <ctx_handler.h>
64
65#if !defined(GIET_NO_HARD_CC)
66# error: You must define GIET_NO_HARD_CC in the giet_config.h file
67#endif
68
69///////////////////////////////////////////////////////////////////////////////
70// BDV global variables
71///////////////////////////////////////////////////////////////////////////////
72
73#define in_unckdata __attribute__((section (".unckdata")))
74#define in_kdata __attribute__((section (".kdata")))
75
76#if GIET_NO_HARD_CC
77in_unckdata giet_lock_t           _bdv_lock __attribute__((aligned(64)));
78in_unckdata volatile unsigned int _bdv_status;
79in_unckdata volatile unsigned int _bdv_gtid;
80#else
81in_kdata giet_lock_t           _bdv_lock __attribute__((aligned(64)));
82in_kdata volatile unsigned int _bdv_status;
83in_kdata volatile unsigned int _bdv_gtid;
84#endif
85
86///////////////////////////////////////////////////////////////////////////////
87// This low_level function returns the value contained in register (index).
88///////////////////////////////////////////////////////////////////////////////
89unsigned int _bdv_get_register( unsigned int index )
90{
91    unsigned int* vaddr = (unsigned int*)SEG_IOC_BASE + index;
92    return _io_extended_read( vaddr );
93}
94
95///////////////////////////////////////////////////////////////////////////////
96// This low-level function set a new value in register (index).
97///////////////////////////////////////////////////////////////////////////////
98void _bdv_set_register( unsigned int index,
99                        unsigned int value ) 
100{
101    unsigned int* vaddr = (unsigned int*)SEG_IOC_BASE + index;
102    _io_extended_write( vaddr, value );
103}
104
105///////////////////////////////////////////////////////////////////////////////
106// This function transfer data between a memory buffer and the block device.
107// The buffer lentgth is (count*block_size) bytes.
108// Arguments are:
109// - to_mem     : from external storage to memory when non 0.
110// - mode       : BOOT / KERNEL / USER
111// - lba        : first block index on the external storage.
112// - buf_paddr  : physical base address of the memory buffer.
113// - count      : number of blocks to be transfered.
114// Returns 0 if success, > 0 if error.
115///////////////////////////////////////////////////////////////////////////////
116static unsigned int _bdv_access( unsigned int       to_mem,
117                                 unsigned int       mode,
118                                 unsigned int       lba,
119                                 unsigned long long buf_paddr,
120                                 unsigned int       count) 
121{
122
123#if GIET_DEBUG_IOC_DRIVER
124unsigned int procid  = _get_procid();
125unsigned int cxy     = procid / NB_PROCS_MAX;
126unsigned int lpid    = procid % NB_PROCS_MAX;
127unsigned int x       = cxy >> Y_WIDTH;
128unsigned int y       = cxy & ((1<<Y_WIDTH) - 1);
129
130_printf("\n[BDV DEBUG] Processor[%d,%d,%d] enters _bdv_access() at cycle %d\n"
131        " - mode    = %d\n"
132        " - paddr   = %l\n"
133        " - sectors = %x\n"
134        " - lba     = %x\n",
135        x, y, lpid, _get_proctime(), mode, buf_paddr, count, lba );
136#endif
137
138    unsigned int       error = 0;
139
140    // get the lock protecting BDV
141    _get_lock(&_bdv_lock);
142
143    // set device registers
144    _bdv_set_register( BLOCK_DEVICE_BUFFER    , (unsigned int)buf_paddr );
145    _bdv_set_register( BLOCK_DEVICE_BUFFER_EXT, (unsigned int)(buf_paddr>>32) );
146    _bdv_set_register( BLOCK_DEVICE_COUNT     , count );
147    _bdv_set_register( BLOCK_DEVICE_LBA       , lba );
148
149#if GIET_DEBUG_IOC_DRIVER
150_printf("\n[BDV DEBUG] _bdv_access() : config registers set\n");
151#endif
152
153    // In BOOT mode, we launch transfer, and poll the BDV_STATUS
154    // register because IRQs are masked.
155    if ( mode == IOC_BOOT_MODE ) 
156    {
157        // Launch transfert
158        if (to_mem == 0) _bdv_set_register( BLOCK_DEVICE_OP, BLOCK_DEVICE_WRITE );
159        else             _bdv_set_register( BLOCK_DEVICE_OP, BLOCK_DEVICE_READ );
160
161#if GIET_DEBUG_IOC_DRIVER
162_printf("\n[BDV DEBUG] _bdv_access() : transfert launched in polling mode\n");
163#endif
164        unsigned int status;
165        do
166        {
167            status = _bdv_get_register( BLOCK_DEVICE_STATUS );
168
169#if GIET_DEBUG_IOC_DRIVER
170_printf("\n[BDV DEBUG] _bdv_access() : ... waiting on BDV_STATUS register ...\n");
171#endif
172        }
173        while( (status != BLOCK_DEVICE_READ_SUCCESS)  &&
174               (status != BLOCK_DEVICE_READ_ERROR)    &&
175               (status != BLOCK_DEVICE_WRITE_SUCCESS) &&
176               (status != BLOCK_DEVICE_WRITE_ERROR)   );      // busy waiting
177
178        // analyse status
179        error = ( (status == BLOCK_DEVICE_READ_ERROR) ||
180                  (status == BLOCK_DEVICE_WRITE_ERROR) );
181
182        // release lock
183        _release_lock(&_bdv_lock);     
184    }
185    // in USER or KERNEL mode, we deschedule the task.
186    // When the task is rescheduled, we check the _bdv_status variable,
187    // and release the lock.
188    // We need a critical section, because we must reset the RUN bit
189        // before to launch the transfer, and we don't want to be descheduled
190        // between these two operations.
191    else
192    {
193        unsigned int save_sr;
194        unsigned int ltid = _get_current_task_id();
195        unsigned int gpid = _get_procid();
196
197        // activates BDV interrupts
198        _bdv_set_register( BLOCK_DEVICE_IRQ_ENABLE, 1 );
199
200        // set the _bdv_status variable
201        _bdv_status = BLOCK_DEVICE_BUSY;
202
203        // enters critical section
204        _it_disable( &save_sr ); 
205
206        // set _bdv_gtid and reset runnable
207        _bdv_gtid = (gpid<<16) + ltid;
208        _set_task_slot( gpid, ltid, CTX_RUN_ID, 0 ); 
209       
210        // launch transfer
211        if (to_mem == 0) _bdv_set_register( BLOCK_DEVICE_OP, BLOCK_DEVICE_WRITE );
212        else             _bdv_set_register( BLOCK_DEVICE_OP, BLOCK_DEVICE_READ  );
213
214#if GIET_DEBUG_IOC_DRIVER
215_printf("\n[BDV DEBUG] _bdv_access() : transfert lauched in interrupt mode\n");
216#endif
217        // deschedule task
218        _ctx_switch();                     
219
220        // restore SR
221        _it_restore( &save_sr );
222
223        // analyse status
224        error = ( (_bdv_status == BLOCK_DEVICE_READ_ERROR) ||
225                  (_bdv_status == BLOCK_DEVICE_WRITE_ERROR) );
226
227        // reset _bdv_status and release lock
228        _bdv_status = BLOCK_DEVICE_IDLE; 
229        _release_lock(&_bdv_lock);     
230    }
231
232#if GIET_DEBUG_IOC_DRIVER
233_printf("\n[BDV DEBUG] Processor[%d,%d,%d] exit _bdv_access() at cycle %d\n",
234        x, y, lpid, _get_proctime() );
235#endif
236
237    return error;
238} // end _bdv_access()
239
240///////////////////////////////////////////////////////////////////////////////
241// This function cheks block size, and desactivates the interrupts.
242// Return 0 for success, > 0 if error
243///////////////////////////////////////////////////////////////////////////////
244unsigned int _bdv_init()
245{
246    if ( _bdv_get_register( BLOCK_DEVICE_BLOCK_SIZE ) != 512 )
247    {
248        _printf("\n[GIET ERROR] in _bdv_init() : block size must be 512 bytes\n");
249        return 1; 
250    }
251
252    _bdv_set_register( BLOCK_DEVICE_IRQ_ENABLE, 0 );
253    return 0;
254}
255
256///////////////////////////////////////////////////////////////////////////////
257// Transfer data from the block device to a memory buffer.
258// - mode     : BOOT / KERNEL / USER
259// - lba      : first block index on the block device
260// - buffer   : base address of the memory buffer (must be word aligned)
261// - count    : number of blocks to be transfered.
262// Returns 0 if success, > 0 if error.
263///////////////////////////////////////////////////////////////////////////////
264unsigned int _bdv_read( unsigned int       mode, 
265                        unsigned int       lba, 
266                        unsigned long long buffer, 
267                        unsigned int       count) 
268{
269    return _bdv_access( 1,        // read access
270                        mode, 
271                        lba,
272                        buffer,
273                        count );
274}
275
276///////////////////////////////////////////////////////////////////////////////
277// Transfer data from a memory buffer to the block device.
278// - mode     : BOOT / KERNEL / USER
279// - lba      : first block index on the block device
280// - buffer   : base address of the memory buffer (must be word aligned)
281// - count    : number of blocks to be transfered.
282// Returns 0 if success, > 0 if error.
283///////////////////////////////////////////////////////////////////////////////
284unsigned int _bdv_write( unsigned int       mode, 
285                         unsigned int       lba, 
286                         unsigned long long buffer, 
287                         unsigned int       count ) 
288{
289    return _bdv_access( 0,        // write access
290                        mode, 
291                        lba,
292                        buffer,
293                        count );
294}
295
296///////////////////////////////////////////////////////////////////////////////
297// Returns device status.
298///////////////////////////////////////////////////////////////////////////////
299unsigned int _bdv_get_status()
300{
301    return _bdv_get_register( BLOCK_DEVICE_STATUS );
302}
303
304///////////////////////////////////////////////////////////////////////////////
305// Returns block size.
306///////////////////////////////////////////////////////////////////////////////
307unsigned int _bdv_get_block_size()
308{
309    return _bdv_get_register( BLOCK_DEVICE_BLOCK_SIZE );
310}
311
312///////////////////////////////////////////////////////////////////////////////////
313// This ISR save the status, acknowledge the IRQ,
314// and activates the task waiting on IO transfer.
315// It can be an HWI or a SWI.
316//
317// TODO the _set_task_slot access should be replaced by an atomic LL/SC
318//      when the CTX_RUN bool will be replaced by a bit_vector.
319///////////////////////////////////////////////////////////////////////////////////
320void _bdv_isr( unsigned int irq_type,   // HWI / WTI
321               unsigned int irq_id,     // index returned by ICU
322               unsigned int channel )   // unused
323{
324    // get BDV status (and reset IRQ)
325    unsigned int status =  _bdv_get_register( BLOCK_DEVICE_STATUS ); 
326
327    // check status: does nothing if IDLE or BUSY
328    if ( (status == BLOCK_DEVICE_IDLE) ||
329         (status == BLOCK_DEVICE_BUSY) )   return;
330 
331    // save status in kernel buffer _bdv_status
332    _bdv_status = status; 
333
334    // identify task waiting on BDV
335    unsigned int rprocid     = _bdv_gtid>>16;
336    unsigned int ltid        = _bdv_gtid & 0xFFFF;
337    unsigned int remote_xy   = rprocid / NB_PROCS_MAX;
338    unsigned int remote_lpid = rprocid % NB_PROCS_MAX;
339
340    // re-activates sleeping task
341    _set_task_slot( rprocid,     // global processor index
342                    ltid,        // local task index on processor
343                    CTX_RUN_ID,  // CTX_RUN slot
344                    1 );         // running
345
346    // requires a context switch for remote processor running the waiting task
347    _xcu_send_wti( remote_xy,    // remote cluster index
348                   remote_lpid,  // remote local processor index
349                   0 );          // don't force context switch if not idle
350
351#if GIET_DEBUG_IRQS  // we don't take the TTY lock to avoid deadlock
352unsigned int procid     = _get_procid();
353unsigned int cluster_xy = procid / NB_PROCS_MAX;
354unsigned int lpid       = procid % NB_PROCS_MAX;
355unsigned int x              = cluster_xy >> Y_WIDTH;
356unsigned int y              = cluster_xy & ((1<<Y_WIDTH)-1);
357unsigned int rx             = remote_xy >> Y_WIDTH;
358unsigned int ry             = remote_xy & ((1<<Y_WIDTH)-1);
359_puts("\n[IRQS DEBUG] Processor[");
360_putd(x );
361_puts(",");
362_putd(y );
363_puts(",");
364_putd(lpid );
365_puts("] enters _bdv_isr() at cycle ");
366_putd(_get_proctime() );
367_puts("\n  for task ");
368_putd(ltid );
369_puts(" running on processor[");
370_putd(rx );
371_puts(",");
372_putd(ry );
373_puts(",");
374_putd(remote_lpid );
375_puts(" / bdv status = ");
376_putx(_bdv_status );
377_puts("\n");
378#endif
379
380}
381
382
383// Local Variables:
384// tab-width: 4
385// c-basic-offset: 4
386// c-file-offsets:((innamespace . 0)(inline-open . 0))
387// indent-tabs-mode: nil
388// End:
389// vim: filetype=c:expandtab:shiftwidth=4:tabstop=4:softtabstop=4
390
Note: See TracBrowser for help on using the repository browser.