63 lines
2.1 KiB
C
63 lines
2.1 KiB
C
/* The system call implemented in this file:
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* m_type: SYS_SDEVIO
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*
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* The parameters for this system call are:
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* m2_i3: DIO_REQUEST (request input or output)
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* m2_i1: DIO_TYPE (flag indicating byte, word, or long)
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* m2_l1: DIO_PORT (port to read/ write)
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* m2_p1: DIO_VEC_ADDR (virtual address of buffer)
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* m2_l2: DIO_VEC_SIZE (number of elements)
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* m2_i2: DIO_VEC_PROC (process where buffer is)
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*/
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#include "../system.h"
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#include <minix/devio.h>
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#if USE_SDEVIO
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/*===========================================================================*
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* do_sdevio *
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*===========================================================================*/
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PUBLIC int do_sdevio(m_ptr)
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register message *m_ptr; /* pointer to request message */
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{
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int proc_nr = m_ptr->DIO_VEC_PROC;
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int count = m_ptr->DIO_VEC_SIZE;
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long port = m_ptr->DIO_PORT;
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phys_bytes phys_buf;
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/* Check if process number is OK. A process number is allowed here, because
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* driver may directly provide a pointer to a buffer at the user-process
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* that initiated the device I/O. Kernel processes, of course, are denied.
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*/
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if (proc_nr == SELF) proc_nr = m_ptr->m_source;
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if (! isokprocn(proc_nr)) return(EINVAL);
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if (iskerneln(proc_nr)) return(EPERM);
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/* Get and check physical address. */
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if ((phys_buf = numap_local(proc_nr, (vir_bytes) m_ptr->DIO_VEC_ADDR, count)) == 0)
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return(EFAULT);
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/* Perform device I/O for bytes and words. Longs are not supported. */
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if (m_ptr->DIO_REQUEST == DIO_INPUT) {
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switch (m_ptr->DIO_TYPE) {
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case DIO_BYTE: phys_insb(port, phys_buf, count); break;
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case DIO_WORD: phys_insw(port, phys_buf, count); break;
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default: return(EINVAL);
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}
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} else if (m_ptr->DIO_REQUEST == DIO_OUTPUT) {
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switch (m_ptr->DIO_TYPE) {
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case DIO_BYTE: phys_outsb(port, phys_buf, count); break;
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case DIO_WORD: phys_outsw(port, phys_buf, count); break;
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default: return(EINVAL);
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}
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}
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else {
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return(EINVAL);
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}
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return(OK);
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}
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#endif /* USE_SDEVIO */
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