mkinitrd-magellan/isolinux/serirq.inc

;; -----------------------------------------------------------------------
;;
;;   Copyright 2009 Intel Corporation; author: H. Peter Anvin
;;
;;   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, Inc., 53 Temple Place Ste 330,
;;   Boston MA 02111-1307, USA; either version 2 of the License, or
;;   (at your option) any later version; incorporated herein by reference.
;;
;; -----------------------------------------------------------------------

;;
;; serirq.inc
;;
;; Serial port IRQ code
;;
;; We don't know what IRQ, if any, we have, so map all of them...
;;

		section .text
		bits 16
		align 8

		section .bss
		alignb 8

%assign n 0
%rep 16
		section .text
serstub_irq %+ n :
		push dword [cs:oldirq %+ n]
		jmp short irq_common

		section .bss
oldirq %+ n	resd 1
%assign n n+1
%endrep

		section .text
irq_common:
		pushf
		push ax
		push dx
		mov dx,[cs:SerialPort]
		add dx,5			; DX -> LSR
		in al,dx
		test al,1			; Received data
		jnz .data
.done:
		pop dx
		pop ax
		popf
		retf				; Chain to next handler
.data:
		push es
		push di
		mov ax,aux_seg + (aux.serial >> 4)
		mov es,ax
		mov di,[cs:SerialHead]
.loop:
		mov dx,[cs:SerialPort]		; DX -> RDR
		in al,dx
		stosb
		mov ah,[cs:FlowIgnore]
		add dx,5			; DX -> LSR
		in al,dx
		push ax
		and al,ah
		cmp al,ah
		jne .drop
		and di,serial_buf_size-1	; Wrap around if necessary
		cmp di,[cs:SerialTail]		; Would this cause overflow?
		je .drop			; If so, just drop the data
		mov [cs:SerialHead],di
.drop:
		pop ax
		test al,1			; More data?
		jnz .loop
.full:
		pop di
		pop es
		jmp .done

		section .data
;
; SerialIRQPort will generally track SerialPort, but will be 0 when an
; IRQ service is not installed.
;
SerialIRQPort	dw 0			; Serial port w IRQ service
SerialHead	dw 0			; Head of serial port rx buffer
SerialTail	dw 0			; Tail of serial port rx buffer

		section .bss
IRQMask		resw 1			; PIC IRQ mask status

		section .text

sirq_install:
		pushad

		call sirq_cleanup

		; Save the old interrupt vectors
		mov si,4*08h
		mov di,oldirq0
		mov cx,8
		rep movsd
		mov si,4*70h
		mov cx,8
		rep movsd

		; Install new interrupt vectors
		mov di,4*08h
		mov cx,8
		mov eax,serstub_irq0
.pic0:
		stosd
		add ax,serstub_irq1 - serstub_irq0
		loop .pic0
		mov di,4*70h
		mov cx,8
.pic1:
		stosd
		add ax,serstub_irq1 - serstub_irq0
		loop .pic1

		mov bx,[SerialPort]
		mov [SerialIRQPort],bx

		lea dx,[bx+5]		; DX -> LCR
		mov al,03h		; Clear DLAB (should already be...)
		slow_out dx,al

		lea dx,[bx+1]		; DX -> IER
		mov al,1		; Enable receive interrupt
		slow_out dx,al

		;
		; Enable all ther interupt lines at the PIC.  Some BIOSes
		; only enable the timer interrupts and other interrupts
		; actively in use by the BIOS.
		;
		in al,0xA1		; Secondary PIC mask register
		mov ah,al
		in al,0x21		; Primary PIC mask register
		mov [IRQMask],ax

		io_delay

		xor ax,ax		; Remove all interrupt masks
		out 0x21,al
		out 0xA1,al

		popad
		ret

sirq_cleanup_nowipe:
		pushad
		push ds
		push es
		xor ax,ax
		mov ds,ax
		mov es,ax

		mov bx,[SerialIRQPort]
		and bx,bx
		jz .done

		lea dx,[bx+5]		; DX -> LCR
		mov al,03h		; Clear DLAB (should already be...)
		slow_out dx,al

		lea dx,[bx+1]		; DX -> IER
		xor ax,ax
		slow_out dx,al		; Clear IER

		; Restore PIC masks
		mov ax,[IRQMask]
		out 0x21,al
		mov al,ah
		out 0xA1,al

		; Restore the original interrupt vectors
		mov si,oldirq0
		mov di,4*08h
		mov cx,8
		rep movsd
		mov di,4*70h
		mov cx,8
		rep movsd

		xor ax,ax
		mov [SerialIRQPort],ax		; No active interrupt system

.done:
		pop es
		pop ds
		popad
		ret

sirq_cleanup:
		call sirq_cleanup_nowipe
		pushad
		push es
		; Just in case it might contain a password, erase the
		; serial port receive buffer...
		mov ax,aux_seg + (aux.serial >> 4)
		mov es,ax
		xor eax,eax
		mov [cs:SerialHead],eax
		mov cx,serial_buf_size >> 2
		xor di,di
		rep stosd
		pop es
		popad
		ret

		section .text
1	;; -----------------------------------------------------------------------
2	;;
3	;; Copyright 2009 Intel Corporation; author: H. Peter Anvin
4	;;
5	;; This program is free software; you can redistribute it and/or modify
6	;; it under the terms of the GNU General Public License as published by
7	;; the Free Software Foundation, Inc., 53 Temple Place Ste 330,
8	;; Boston MA 02111-1307, USA; either version 2 of the License, or
9	;; (at your option) any later version; incorporated herein by reference.
10	;;
11	;; -----------------------------------------------------------------------
12
13	;;
14	;; serirq.inc
15	;;
16	;; Serial port IRQ code
17	;;
18	;; We don't know what IRQ, if any, we have, so map all of them...
19	;;
20
21	section .text
22	bits 16
23	align 8
24
25	section .bss
26	alignb 8
27
28	%assign n 0
29	%rep 16
30	section .text
31	serstub_irq %+ n :
32	push dword [cs:oldirq %+ n]
33	jmp short irq_common
34
35	section .bss
36	oldirq %+ n resd 1
37	%assign n n+1
38	%endrep
39
40	section .text
41	irq_common:
42	pushf
43	push ax
44	push dx
45	mov dx,[cs:SerialPort]
46	add dx,5 ; DX -> LSR
47	in al,dx
48	test al,1 ; Received data
49	jnz .data
50	.done:
51	pop dx
52	pop ax
53	popf
54	retf ; Chain to next handler
55	.data:
56	push es
57	push di
58	mov ax,aux_seg + (aux.serial >> 4)
59	mov es,ax
60	mov di,[cs:SerialHead]
61	.loop:
62	mov dx,[cs:SerialPort] ; DX -> RDR
63	in al,dx
64	stosb
65	mov ah,[cs:FlowIgnore]
66	add dx,5 ; DX -> LSR
67	in al,dx
68	push ax
69	and al,ah
70	cmp al,ah
71	jne .drop
72	and di,serial_buf_size-1 ; Wrap around if necessary
73	cmp di,[cs:SerialTail] ; Would this cause overflow?
74	je .drop ; If so, just drop the data
75	mov [cs:SerialHead],di
76	.drop:
77	pop ax
78	test al,1 ; More data?
79	jnz .loop
80	.full:
81	pop di
82	pop es
83	jmp .done
84
85	section .data
86	;
87	; SerialIRQPort will generally track SerialPort, but will be 0 when an
88	; IRQ service is not installed.
89	;
90	SerialIRQPort dw 0 ; Serial port w IRQ service
91	SerialHead dw 0 ; Head of serial port rx buffer
92	SerialTail dw 0 ; Tail of serial port rx buffer
93
94	section .bss
95	IRQMask resw 1 ; PIC IRQ mask status
96
97	section .text
98
99	sirq_install:
100	pushad
101
102	call sirq_cleanup
103
104	; Save the old interrupt vectors
105	mov si,4*08h
106	mov di,oldirq0
107	mov cx,8
108	rep movsd
109	mov si,4*70h
110	mov cx,8
111	rep movsd
112
113	; Install new interrupt vectors
114	mov di,4*08h
115	mov cx,8
116	mov eax,serstub_irq0
117	.pic0:
118	stosd
119	add ax,serstub_irq1 - serstub_irq0
120	loop .pic0
121	mov di,4*70h
122	mov cx,8
123	.pic1:
124	stosd
125	add ax,serstub_irq1 - serstub_irq0
126	loop .pic1
127
128	mov bx,[SerialPort]
129	mov [SerialIRQPort],bx
130
131	lea dx,[bx+5] ; DX -> LCR
132	mov al,03h ; Clear DLAB (should already be...)
133	slow_out dx,al
134
135	lea dx,[bx+1] ; DX -> IER
136	mov al,1 ; Enable receive interrupt
137	slow_out dx,al
138
139	;
140	; Enable all ther interupt lines at the PIC. Some BIOSes
141	; only enable the timer interrupts and other interrupts
142	; actively in use by the BIOS.
143	;
144	in al,0xA1 ; Secondary PIC mask register
145	mov ah,al
146	in al,0x21 ; Primary PIC mask register
147	mov [IRQMask],ax
148
149	io_delay
150
151	xor ax,ax ; Remove all interrupt masks
152	out 0x21,al
153	out 0xA1,al
154
155	popad
156	ret
157
158	sirq_cleanup_nowipe:
159	pushad
160	push ds
161	push es
162	xor ax,ax
163	mov ds,ax
164	mov es,ax
165
166	mov bx,[SerialIRQPort]
167	and bx,bx
168	jz .done
169
170	lea dx,[bx+5] ; DX -> LCR
171	mov al,03h ; Clear DLAB (should already be...)
172	slow_out dx,al
173
174	lea dx,[bx+1] ; DX -> IER
175	xor ax,ax
176	slow_out dx,al ; Clear IER
177
178	; Restore PIC masks
179	mov ax,[IRQMask]
180	out 0x21,al
181	mov al,ah
182	out 0xA1,al
183
184	; Restore the original interrupt vectors
185	mov si,oldirq0
186	mov di,4*08h
187	mov cx,8
188	rep movsd
189	mov di,4*70h
190	mov cx,8
191	rep movsd
192
193	xor ax,ax
194	mov [SerialIRQPort],ax ; No active interrupt system
195
196	.done:
197	pop es
198	pop ds
199	popad
200	ret
201
202	sirq_cleanup:
203	call sirq_cleanup_nowipe
204	pushad
205	push es
206	; Just in case it might contain a password, erase the
207	; serial port receive buffer...
208	mov ax,aux_seg + (aux.serial >> 4)
209	mov es,ax
210	xor eax,eax
211	mov [cs:SerialHead],eax
212	mov cx,serial_buf_size >> 2
213	xor di,di
214	rep stosd
215	pop es
216	popad
217	ret
218
219	section .text