arch/tile/include/gxio/uart.h

   1 /*
   2  * Copyright 2013 Tilera Corporation. All Rights Reserved.
   3  *
   4  *   This program is free software; you can redistribute it and/or
   5  *   modify it under the terms of the GNU General Public License
   6  *   as published by the Free Software Foundation, version 2.
   7  *
   8  *   This program is distributed in the hope that it will be useful, but
   9  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  11  *   NON INFRINGEMENT.  See the GNU General Public License for
  12  *   more details.
  13  */
  14
  15 #ifndef _GXIO_UART_H_
  16 #define _GXIO_UART_H_
  17
  18 #include "common.h"
  19
  20 #include <hv/drv_uart_intf.h>
  21 #include <hv/iorpc.h>
  22
  23 /*
  24  *
  25  * An API for manipulating UART interface.
  26  */
  27
  28 /*
  29  *
  30  * The Rshim allows access to the processor's UART interface.
  31  */
  32
  33 /* A context object used to manage UART resources. */
  34 typedef struct {
  35
  36         /* File descriptor for calling up to the hypervisor. */
  37         int fd;
  38
  39         /* The VA at which our MMIO registers are mapped. */
  40         char *mmio_base;
  41
  42 } gxio_uart_context_t;
  43
  44 /* Request UART interrupts.
  45  *
  46  *  Request that interrupts be delivered to a tile when the UART's
  47  *  Receive FIFO is written, or the Write FIFO is read.
  48  *
  49  * @param context Pointer to a properly initialized gxio_uart_context_t.
  50  * @param bind_cpu_x X coordinate of CPU to which interrupt will be delivered.
  51  * @param bind_cpu_y Y coordinate of CPU to which interrupt will be delivered.
  52  * @param bind_interrupt IPI interrupt number.
  53  * @param bind_event Sub-interrupt event bit number; a negative value can
  54  *  disable the interrupt.
  55  * @return Zero if all of the requested UART events were successfully
  56  *  configured to interrupt.
  57  */
  58 extern int gxio_uart_cfg_interrupt(gxio_uart_context_t *context,
  59                                    int bind_cpu_x,
  60                                    int bind_cpu_y,
  61                                    int bind_interrupt, int bind_event);
  62
  63 /* Initialize a UART context.
  64  *
  65  *  A properly initialized context must be obtained before any of the other
  66  *  gxio_uart routines may be used.
  67  *
  68  * @param context Pointer to a gxio_uart_context_t, which will be initialized
  69  *  by this routine, if it succeeds.
  70  * @param uart_index Index of the UART to use.
  71  * @return Zero if the context was successfully initialized, else a
  72  *  GXIO_ERR_xxx error code.
  73  */
  74 extern int gxio_uart_init(gxio_uart_context_t *context, int uart_index);
  75
  76 /* Destroy a UART context.
  77  *
  78  *  Once destroyed, a context may not be used with any gxio_uart routines
  79  *  other than gxio_uart_init().  After this routine returns, no further
  80  *  interrupts requested on this context will be delivered.  The state and
  81  *  configuration of the pins which had been attached to this context are
  82  *  unchanged by this operation.
  83  *
  84  * @param context Pointer to a gxio_uart_context_t.
  85  * @return Zero if the context was successfully destroyed, else a
  86  *  GXIO_ERR_xxx error code.
  87  */
  88 extern int gxio_uart_destroy(gxio_uart_context_t *context);
  89
  90 /* Write UART register.
  91  * @param context Pointer to a gxio_uart_context_t.
  92  * @param offset UART register offset.
  93  * @param word Data will be wrote to UART reigister.
  94  */
  95 extern void gxio_uart_write(gxio_uart_context_t *context, uint64_t offset,
  96                             uint64_t word);
  97
  98 /* Read UART register.
  99  * @param context Pointer to a gxio_uart_context_t.
 100  * @param offset UART register offset.
 101  * @return Data read from UART register.
 102  */
 103 extern uint64_t gxio_uart_read(gxio_uart_context_t *context, uint64_t offset);
 104
 105 #endif /* _GXIO_UART_H_ */