tpm/st33zp24/spi: Remove nbr_dummy_bytes variable usage
[deliverable/linux.git] / arch / mn10300 / kernel / mn10300-serial-low.S
CommitLineData
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1###############################################################################
2#
3# Virtual DMA driver for MN10300 serial ports
4#
5# Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
6# Written by David Howells (dhowells@redhat.com)
7#
8# This program is free software; you can redistribute it and/or
9# modify it under the terms of the GNU General Public Licence
10# as published by the Free Software Foundation; either version
11# 2 of the Licence, or (at your option) any later version.
12#
13###############################################################################
14#include <linux/sys.h>
15#include <linux/linkage.h>
16#include <asm/page.h>
17#include <asm/smp.h>
18#include <asm/cpu-regs.h>
19#include <asm/frame.inc>
20#include <asm/timer-regs.h>
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21#include <proc/cache.h>
22#include <unit/timex.h>
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23#include "mn10300-serial.h"
24
25#define SCxCTR 0x00
26#define SCxICR 0x04
27#define SCxTXB 0x08
28#define SCxRXB 0x09
29#define SCxSTR 0x0c
30#define SCxTIM 0x0d
31
32 .text
33
34###############################################################################
35#
36# serial port interrupt virtual DMA entry point
37# - intended to run at interrupt priority 1 (not affected by local_irq_disable)
38#
39###############################################################################
40 .balign L1_CACHE_BYTES
41ENTRY(mn10300_serial_vdma_interrupt)
368dd5ac 42# or EPSW_IE,psw # permit overriding by
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43 # debugging interrupts
44 movm [d2,d3,a2,a3,exreg0],(sp)
45
46 movhu (IAGR),a2 # see if which interrupt is
47 # pending
48 and IAGR_GN,a2
49 add a2,a2
50 add mn10300_serial_int_tbl,a2
51
52 mov (a2+),a3
53 mov (__iobase,a3),e2
54 mov (a2),a2
55 jmp (a2)
56
57###############################################################################
58#
59# serial port receive interrupt virtual DMA entry point
60# - intended to run at interrupt priority 1 (not affected by local_irq_disable)
61# - stores data/status byte pairs in the ring buffer
62# - induces a scheduler tick timer interrupt when done, which we then subvert
63# on entry:
64# A3 struct mn10300_serial_port *
65# E2 I/O port base
66#
67###############################################################################
68ENTRY(mn10300_serial_vdma_rx_handler)
69 mov (__rx_icr,a3),e3
70 mov GxICR_DETECT,d2
71 movbu d2,(e3) # ACK the interrupt
72 movhu (e3),d2 # flush
73
74 mov (__rx_inp,a3),d3
75 mov d3,a2
76 add 2,d3
77 and MNSC_BUFFER_SIZE-1,d3
78 mov (__rx_outp,a3),d2
79 cmp d3,d2
80 beq mnsc_vdma_rx_overflow
81
82 mov (__rx_buffer,a3),d2
83 add d2,a2
84 movhu (SCxSTR,e2),d2
85 movbu d2,(1,a2)
86 movbu (SCxRXB,e2),d2
87 movbu d2,(a2)
88 mov d3,(__rx_inp,a3)
89 bset MNSCx_RX_AVAIL,(__intr_flags,a3)
90
91mnsc_vdma_rx_done:
92 mov (__tm_icr,a3),a2
93 mov GxICR_LEVEL_6|GxICR_ENABLE|GxICR_REQUEST|GxICR_DETECT,d2
94 movhu d2,(a2) # request a slow interrupt
95 movhu (a2),d2 # flush
96
97 movm (sp),[d2,d3,a2,a3,exreg0]
98 rti
99
100mnsc_vdma_rx_overflow:
101 bset MNSCx_RX_OVERF,(__intr_flags,a3)
102 bra mnsc_vdma_rx_done
103
104###############################################################################
105#
106# serial port transmit interrupt virtual DMA entry point
107# - intended to run at interrupt priority 1 (not affected by local_irq_disable)
108# - retrieves data bytes from the ring buffer and passes them to the serial port
109# - induces a scheduler tick timer interrupt when done, which we then subvert
110# A3 struct mn10300_serial_port *
111# E2 I/O port base
112#
113###############################################################################
114 .balign L1_CACHE_BYTES
115ENTRY(mn10300_serial_vdma_tx_handler)
116 mov (__tx_icr,a3),e3
117 mov GxICR_DETECT,d2
118 movbu d2,(e3) # ACK the interrupt
119 movhu (e3),d2 # flush
120
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121 btst 0xFF,(__tx_flags,a3) # handle transmit flags
122 bne mnsc_vdma_tx_flags
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123
124 movbu (SCxSTR,e2),d2 # don't try and transmit a char if the
125 # buffer is not empty
126 btst SC01STR_TBF,d2 # (may have tried to jumpstart)
127 bne mnsc_vdma_tx_noint
128
129 movbu (__tx_xchar,a3),d2 # handle hi-pri XON/XOFF
130 or d2,d2
131 bne mnsc_vdma_tx_xchar
132
70430786 133 mov (__uart_state,a3),a2 # see if the TTY Tx queue has anything in it
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134 mov (__xmit_tail,a2),d3
135 mov (__xmit_head,a2),d2
136 cmp d3,d2
137 beq mnsc_vdma_tx_empty
138
139 mov (__xmit_buffer,a2),d2 # get a char from the buffer and
140 # transmit it
141 movbu (d3,d2),d2
142 movbu d2,(SCxTXB,e2) # Tx
143
144 inc d3 # advance the buffer pointer
145 and __UART_XMIT_SIZE-1,d3
146 mov (__xmit_head,a2),d2
147 mov d3,(__xmit_tail,a2)
148
149 sub d3,d2 # see if we've written everything
150 beq mnsc_vdma_tx_empty
151
152 and __UART_XMIT_SIZE-1,d2 # see if we just made a hole
153 cmp __UART_XMIT_SIZE-2,d2
154 beq mnsc_vdma_tx_made_hole
155
156mnsc_vdma_tx_done:
157 mov (__tm_icr,a3),a2
158 mov GxICR_LEVEL_6|GxICR_ENABLE|GxICR_REQUEST|GxICR_DETECT,d2
159 movhu d2,(a2) # request a slow interrupt
160 movhu (a2),d2 # flush
161
162mnsc_vdma_tx_noint:
163 movm (sp),[d2,d3,a2,a3,exreg0]
164 rti
165
166mnsc_vdma_tx_empty:
368dd5ac 167 mov +(NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL)|GxICR_DETECT),d2
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168 movhu d2,(e3) # disable the interrupt
169 movhu (e3),d2 # flush
170
171 bset MNSCx_TX_EMPTY,(__intr_flags,a3)
172 bra mnsc_vdma_tx_done
173
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174mnsc_vdma_tx_flags:
175 btst MNSCx_TX_STOP,(__tx_flags,a3)
176 bne mnsc_vdma_tx_stop
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177 movhu (SCxCTR,e2),d2 # turn on break mode
178 or SC01CTR_BKE,d2
179 movhu d2,(SCxCTR,e2)
8f0bcbca 180mnsc_vdma_tx_stop:
368dd5ac 181 mov +(NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL)|GxICR_DETECT),d2
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182 movhu d2,(e3) # disable transmit interrupts on this
183 # channel
184 movhu (e3),d2 # flush
185 bra mnsc_vdma_tx_noint
186
187mnsc_vdma_tx_xchar:
188 bclr 0xff,(__tx_xchar,a3)
189 movbu d2,(SCxTXB,e2)
190 bra mnsc_vdma_tx_done
191
192mnsc_vdma_tx_made_hole:
193 bset MNSCx_TX_SPACE,(__intr_flags,a3)
194 bra mnsc_vdma_tx_done
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