76 lines
		
	
	
		
			1.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			76 lines
		
	
	
		
			1.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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 * hvconsole.c
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 * Copyright (C) 2004 Hollis Blanchard, IBM Corporation
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 * Copyright (C) 2004 IBM Corporation
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 *
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 * Additional Author(s):
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 *  Ryan S. Arnold <rsa@us.ibm.com>
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 *
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 * LPAR console support.
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 */
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#include <linux/kernel.h>
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#include <linux/export.h>
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#include <linux/errno.h>
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#include <asm/hvcall.h>
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#include <asm/hvconsole.h>
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#include <asm/plpar_wrappers.h>
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/**
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 * hvc_get_chars - retrieve characters from firmware for denoted vterm adapter
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 * @vtermno: The vtermno or unit_address of the adapter from which to fetch the
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 *	data.
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 * @buf: The character buffer into which to put the character data fetched from
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 *	firmware.
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 * @count: not used?
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 */
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int hvc_get_chars(uint32_t vtermno, char *buf, int count)
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{
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	long ret;
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	unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
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	unsigned long *lbuf = (unsigned long *)buf;
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	ret = plpar_hcall(H_GET_TERM_CHAR, retbuf, vtermno);
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	lbuf[0] = be64_to_cpu(retbuf[1]);
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	lbuf[1] = be64_to_cpu(retbuf[2]);
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	if (ret == H_SUCCESS)
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		return retbuf[0];
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	return 0;
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}
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EXPORT_SYMBOL(hvc_get_chars);
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/**
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 * hvc_put_chars: send characters to firmware for denoted vterm adapter
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 * @vtermno: The vtermno or unit_address of the adapter from which the data
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 *	originated.
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 * @buf: The character buffer that contains the character data to send to
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 *	firmware. Must be at least 16 bytes, even if count is less than 16.
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 * @count: Send this number of characters.
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 */
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int hvc_put_chars(uint32_t vtermno, const char *buf, int count)
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{
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	unsigned long *lbuf = (unsigned long *) buf;
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	long ret;
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	/* hcall will ret H_PARAMETER if 'count' exceeds firmware max.*/
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	if (count > MAX_VIO_PUT_CHARS)
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		count = MAX_VIO_PUT_CHARS;
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	ret = plpar_hcall_norets(H_PUT_TERM_CHAR, vtermno, count,
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				 cpu_to_be64(lbuf[0]),
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				 cpu_to_be64(lbuf[1]));
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	if (ret == H_SUCCESS)
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		return count;
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	if (ret == H_BUSY)
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		return -EAGAIN;
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	return -EIO;
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}
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EXPORT_SYMBOL(hvc_put_chars);
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