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kernel/linux-rt-4.4.41/arch/tile/include/gxio/uart.h 3.35 KB
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  /*
   * Copyright 2013 Tilera Corporation. All Rights Reserved.
   *
   *   This program is free software; you can redistribute it and/or
   *   modify it under the terms of the GNU General Public License
   *   as published by the Free Software Foundation, version 2.
   *
   *   This program is distributed in the hope that it will be useful, but
   *   WITHOUT ANY WARRANTY; without even the implied warranty of
   *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
   *   NON INFRINGEMENT.  See the GNU General Public License for
   *   more details.
   */
  
  #ifndef _GXIO_UART_H_
  #define _GXIO_UART_H_
  
  #include "common.h"
  
  #include <hv/drv_uart_intf.h>
  #include <hv/iorpc.h>
  
  /*
   *
   * An API for manipulating UART interface.
   */
  
  /*
   *
   * The Rshim allows access to the processor's UART interface.
   */
  
  /* A context object used to manage UART resources. */
  typedef struct {
  
  	/* File descriptor for calling up to the hypervisor. */
  	int fd;
  
  	/* The VA at which our MMIO registers are mapped. */
  	char *mmio_base;
  
  } gxio_uart_context_t;
  
  /* Request UART interrupts.
   *
   *  Request that interrupts be delivered to a tile when the UART's
   *  Receive FIFO is written, or the Write FIFO is read.
   *
   * @param context Pointer to a properly initialized gxio_uart_context_t.
   * @param bind_cpu_x X coordinate of CPU to which interrupt will be delivered.
   * @param bind_cpu_y Y coordinate of CPU to which interrupt will be delivered.
   * @param bind_interrupt IPI interrupt number.
   * @param bind_event Sub-interrupt event bit number; a negative value can
   *  disable the interrupt.
   * @return Zero if all of the requested UART events were successfully
   *  configured to interrupt.
   */
  extern int gxio_uart_cfg_interrupt(gxio_uart_context_t *context,
  				   int bind_cpu_x,
  				   int bind_cpu_y,
  				   int bind_interrupt, int bind_event);
  
  /* Initialize a UART context.
   *
   *  A properly initialized context must be obtained before any of the other
   *  gxio_uart routines may be used.
   *
   * @param context Pointer to a gxio_uart_context_t, which will be initialized
   *  by this routine, if it succeeds.
   * @param uart_index Index of the UART to use.
   * @return Zero if the context was successfully initialized, else a
   *  GXIO_ERR_xxx error code.
   */
  extern int gxio_uart_init(gxio_uart_context_t *context, int uart_index);
  
  /* Destroy a UART context.
   *
   *  Once destroyed, a context may not be used with any gxio_uart routines
   *  other than gxio_uart_init().  After this routine returns, no further
   *  interrupts requested on this context will be delivered.  The state and
   *  configuration of the pins which had been attached to this context are
   *  unchanged by this operation.
   *
   * @param context Pointer to a gxio_uart_context_t.
   * @return Zero if the context was successfully destroyed, else a
   *  GXIO_ERR_xxx error code.
   */
  extern int gxio_uart_destroy(gxio_uart_context_t *context);
  
  /* Write UART register.
   * @param context Pointer to a gxio_uart_context_t.
   * @param offset UART register offset.
   * @param word Data will be wrote to UART reigister.
   */
  extern void gxio_uart_write(gxio_uart_context_t *context, uint64_t offset,
  			    uint64_t word);
  
  /* Read UART register.
   * @param context Pointer to a gxio_uart_context_t.
   * @param offset UART register offset.
   * @return Data read from UART register.
   */
  extern uint64_t gxio_uart_read(gxio_uart_context_t *context, uint64_t offset);
  
  #endif /* _GXIO_UART_H_ */