source: branches/minix3-book/kernel/system/do_vdevio.c@ 25

Last change on this file since 25 was 4, checked in by Mattia Monga, 14 years ago

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1/* The kernel call implemented in this file:
2 * m_type: SYS_VDEVIO
3 *
4 * The parameters for this kernel call are:
5 * m2_i3: DIO_REQUEST (request input or output)
6 * m2_i1: DIO_TYPE (flag indicating byte, word, or long)
7 * m2_p1: DIO_VEC_ADDR (pointer to port/ value pairs)
8 * m2_i2: DIO_VEC_SIZE (number of ports to read or write)
9 */
10
11#include "../system.h"
12#include <minix/devio.h>
13
14#if USE_VDEVIO
15
16/* Buffer for SYS_VDEVIO to copy (port,value)-pairs from/ to user. */
17PRIVATE char vdevio_buf[VDEVIO_BUF_SIZE];
18PRIVATE pvb_pair_t *pvb = (pvb_pair_t *) vdevio_buf;
19PRIVATE pvw_pair_t *pvw = (pvw_pair_t *) vdevio_buf;
20PRIVATE pvl_pair_t *pvl = (pvl_pair_t *) vdevio_buf;
21
22/*===========================================================================*
23 * do_vdevio *
24 *===========================================================================*/
25PUBLIC int do_vdevio(m_ptr)
26register message *m_ptr; /* pointer to request message */
27{
28/* Perform a series of device I/O on behalf of a non-kernel process. The
29 * I/O addresses and I/O values are fetched from and returned to some buffer
30 * in user space. The actual I/O is wrapped by lock() and unlock() to prevent
31 * that I/O batch from being interrrupted.
32 * This is the counterpart of do_devio, which performs a single device I/O.
33 */
34 int vec_size; /* size of vector */
35 int io_in; /* true if input */
36 size_t bytes; /* # bytes to be copied */
37 int caller_proc; /* process number of caller */
38 vir_bytes caller_vir; /* virtual address at caller */
39 phys_bytes caller_phys; /* physical address at caller */
40 int i;
41
42 /* Get the request, size of the request vector, and check the values. */
43 if (m_ptr->DIO_REQUEST == DIO_INPUT) io_in = TRUE;
44 else if (m_ptr->DIO_REQUEST == DIO_OUTPUT) io_in = FALSE;
45 else return(EINVAL);
46 if ((vec_size = m_ptr->DIO_VEC_SIZE) <= 0) return(EINVAL);
47 switch (m_ptr->DIO_TYPE) {
48 case DIO_BYTE: bytes = vec_size * sizeof(pvb_pair_t); break;
49 case DIO_WORD: bytes = vec_size * sizeof(pvw_pair_t); break;
50 case DIO_LONG: bytes = vec_size * sizeof(pvl_pair_t); break;
51 default: return(EINVAL); /* check type once and for all */
52 }
53 if (bytes > sizeof(vdevio_buf)) return(E2BIG);
54
55 /* Calculate physical addresses and copy (port,value)-pairs from user. */
56 caller_proc = m_ptr->m_source;
57 caller_vir = (vir_bytes) m_ptr->DIO_VEC_ADDR;
58 caller_phys = umap_local(proc_addr(caller_proc), D, caller_vir, bytes);
59 if (0 == caller_phys) return(EFAULT);
60 phys_copy(caller_phys, vir2phys(vdevio_buf), (phys_bytes) bytes);
61
62 /* Perform actual device I/O for byte, word, and long values. Note that
63 * the entire switch is wrapped in lock() and unlock() to prevent the I/O
64 * batch from being interrupted.
65 */
66 lock(13, "do_vdevio");
67 switch (m_ptr->DIO_TYPE) {
68 case DIO_BYTE: /* byte values */
69 if (io_in) for (i=0; i<vec_size; i++) pvb[i].value = inb(pvb[i].port);
70 else for (i=0; i<vec_size; i++) outb(pvb[i].port, pvb[i].value);
71 break;
72 case DIO_WORD: /* word values */
73 if (io_in) for (i=0; i<vec_size; i++) pvw[i].value = inw(pvw[i].port);
74 else for (i=0; i<vec_size; i++) outw(pvw[i].port, pvw[i].value);
75 break;
76 default: /* long values */
77 if (io_in) for (i=0; i<vec_size; i++) pvl[i].value = inl(pvl[i].port);
78 else for (i=0; i<vec_size; i++) outl(pvb[i].port, pvl[i].value);
79 }
80 unlock(13);
81
82 /* Almost done, copy back results for input requests. */
83 if (io_in) phys_copy(vir2phys(vdevio_buf), caller_phys, (phys_bytes) bytes);
84 return(OK);
85}
86
87#endif /* USE_VDEVIO */
88
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