Even more tweaks at flow control supportsyslinux-1.64-pre4

4 files changed, 81 insertions, 25 deletions

diff --git a/isolinux.asm b/isolinux.asm
index 33903d2c..e88d52e0 100644
--- a/isolinux.asm
+++ b/isolinux.asm
@@ -351,6 +351,7 @@ VidRows         resb 1			; Rows on screen-1
 FlowControl	equ $
 FlowOutput	resb 1			; Outputs to assert for serial flow
 FlowInput	resb 1			; Input bits for serial flow
+FlowIgnore	resb 1			; Ignore input unless these bits set
 RetryCount      resb 1			; Used for disk access retries
 KbdFlags	resb 1			; Check for keyboard escapes
 LoadFlags	resb 1			; Loadflags from kernel
@@ -1197,8 +1198,11 @@ pc_serial:	call getint			; "serial" command
 		call ungetc
 		call getint			; Hardware flow control?
 		jnc .valid_flow
-		xor bl,bl			; Default -> no flow control
+		xor bx,bx			; Default -> no flow control
 .valid_flow:
+		and bh,0Fh			; FlowIgnore
+		shl bh,4
+		mov [FlowIgnore],bh
 		mov bh,bl
 		and bx,0F003h			; Valid bits
 		mov [FlowControl],bx
@@ -1237,8 +1241,7 @@ pc_serial:	call getint			; "serial" command
 
 		add dx,byte 3			; DX -> MCR
 		in al,dx
-		mov ah,[FlowOutput]		; DTR and RTS control
-		or al,ah			; Assert bits
+		or al,[FlowOutput]		; Assert bits
 		call slow_out
 
 		; Show some life
@@ -3463,6 +3466,14 @@ pollchar:
 		add dx,byte 5		; DX -> LSR
 		in al,dx
 		test al,1		; ZF = 0 if data pending
+		jz .done
+		inc dx			; DX -> MSR
+		mov ah,[FlowIgnore]	; Required status bits
+		in al,dx
+		and al,ah
+		cmp al,ah
+		setne al
+		dec al			; Set ZF = 0 if equal
 .done:		popad
 		ret
 
@@ -3476,10 +3487,16 @@ getchar:
 		mov bx,[SerialPort]
 		and bx,bx
 		jz .again
-		lea dx,[bx+5]		; Serial status register
+		lea dx,[bx+5]		; DX -> LSR
 		in al,dx
 		test al,1
 		jz .again
+		inc dx			; DX -> MSR
+		mov ah,[FlowIgnore]
+		in al,dx
+		and al,ah
+		cmp al,ah
+		jne .again
 .serial:	xor ah,ah		; Avoid confusion
 		xchg dx,bx		; Data port
 		in al,dx
diff --git a/ldlinux.asm b/ldlinux.asm
index c9b723b7..722e748d 100644
--- a/ldlinux.asm
+++ b/ldlinux.asm
@@ -326,6 +326,7 @@ VidRows         resb 1			; Rows on screen-1
 FlowControl	equ $
 FlowOutput	resb 1			; Outputs to assert for serial flow
 FlowInput	resb 1			; Input bits for serial flow
+FlowIgnore	resb 1			; Ignore input unless these bits set
 RetryCount      resb 1			; Used for disk access retries
 KbdFlags	resb 1			; Check for keyboard escapes
 LoadFlags	resb 1			; Loadflags from kernel
@@ -1295,8 +1296,11 @@ pc_serial:	call getint			; "serial" command
 		call ungetc
 		call getint			; Hardware flow control?
 		jnc .valid_flow
-		xor bl,bl			; Default -> no flow control
+		xor bx,bx			; Default -> no flow control
 .valid_flow:
+		and bh,0Fh			; FlowIgnore
+		shl bh,4
+		mov [FlowIgnore],bh
 		mov bh,bl
 		and bx,0F003h			; Valid bits
 		mov [FlowControl],bx
@@ -1335,8 +1339,7 @@ pc_serial:	call getint			; "serial" command
 
 		add dx,byte 3			; DX -> MCR
 		in al,dx
-		mov ah,[FlowOutput]		; DTR and RTS control
-		or al,ah			; Assert bits
+		or al,[FlowOutput]		; Assert bits
 		call slow_out
 
 		; Show some life
@@ -3415,6 +3418,14 @@ pollchar:
 		add dx,byte 5		; DX -> LSR
 		in al,dx
 		test al,1		; ZF = 0 if data pending
+		jz .done
+		inc dx			; DX -> MSR
+		mov ah,[FlowIgnore]	; Required status bits
+		in al,dx
+		and al,ah
+		cmp al,ah
+		setne al
+		dec al			; Set ZF = 0 if equal
 .done:		popad
 		ret
 
@@ -3428,10 +3439,16 @@ getchar:
 		mov bx,[SerialPort]
 		and bx,bx
 		jz .again
-		lea dx,[bx+5]		; Serial status register
+		lea dx,[bx+5]		; DX -> LSR
 		in al,dx
 		test al,1
 		jz .again
+		inc dx			; DX -> MSR
+		mov ah,[FlowIgnore]
+		in al,dx
+		and al,ah
+		cmp al,ah
+		jne .again
 .serial:	xor ah,ah		; Avoid confusion
 		xchg dx,bx		; Data port
 		in al,dx
diff --git a/pxelinux.asm b/pxelinux.asm
index a2b6a3c4..efcec2cb 100644
--- a/pxelinux.asm
+++ b/pxelinux.asm
@@ -386,6 +386,7 @@ VidRows         resb 1			; Rows on screen-1
 FlowControl	equ $
 FlowOutput	resb 1			; Outputs to assert for serial flow
 FlowInput	resb 1			; Input bits for serial flow
+FlowIgnore	resb 1			; Ignore input unless these bits set
 RetryCount      resb 1			; Used for disk access retries
 KbdFlags	resb 1			; Check for keyboard escapes
 LoadFlags	resb 1			; Loadflags from kernel
@@ -1012,8 +1013,11 @@ pc_serial:	call getint			; "serial" command
 		call ungetc
 		call getint			; Hardware flow control?
 		jnc .valid_flow
-		xor bl,bl			; Default -> no flow control
+		xor bx,bx			; Default -> no flow control
 .valid_flow:
+		and bh,0Fh			; FlowIgnore
+		shl bh,4
+		mov [FlowIgnore],bh
 		mov bh,bl
 		and bx,0F003h			; Valid bits
 		mov [FlowControl],bx
@@ -1052,8 +1056,7 @@ pc_serial:	call getint			; "serial" command
 
 		add dx,byte 3			; DX -> MCR
 		in al,dx
-		mov ah,[FlowOutput]		; DTR and RTS control
-		or al,ah			; Assert bits
+		or al,[FlowOutput]		; Assert bits
 		call slow_out
 
 		; Show some life
@@ -3516,6 +3519,14 @@ pollchar:
 		add dx,byte 5		; DX -> LSR
 		in al,dx
 		test al,1		; ZF = 0 if data pending
+		jz .done
+		inc dx			; DX -> MSR
+		mov ah,[FlowIgnore]	; Required status bits
+		in al,dx
+		and al,ah
+		cmp al,ah
+		setne al
+		dec al			; Set ZF = 0 if equal
 .done:		popad
 		ret
 
@@ -3529,10 +3540,16 @@ getchar:
 		mov bx,[SerialPort]
 		and bx,bx
 		jz .again
-		lea dx,[bx+5]		; Serial status register
+		lea dx,[bx+5]		; DX -> LSR
 		in al,dx
 		test al,1
 		jz .again
+		inc dx			; DX -> MSR
+		mov ah,[FlowIgnore]
+		in al,dx
+		and al,ah
+		cmp al,ah
+		jne .again
 .serial:	xor ah,ah		; Avoid confusion
 		xchg dx,bx		; Data port
 		in al,dx
diff --git a/syslinux.doc b/syslinux.doc
index ce6c0236..ffa3884f 100644
--- a/syslinux.doc
+++ b/syslinux.doc
@@ -209,23 +209,28 @@ SERIAL port [[baudrate] flowcontrol]
 	bits, no parity, 1 stop bit.
 
 	"flowcontrol" is a combination of the following bits:
-	  1 - Assert DTR
- 	  2 - Assert RTS
-	 16 - Wait for CTS assertion
-	 32 - Wait for DSR assertion
-	 64 - Wait for RI assertion
-	128 - Wait for DCD assertion
+	0x001 - Assert DTR
+ 	0x002 - Assert RTS
+	0x010 - Wait for CTS assertion
+	0x020 - Wait for DSR assertion
+	0x040 - Wait for RI assertion
+	0x080 - Wait for DCD assertion
+	0x100 - Ignore input unless CTS asserted
+	0x200 - Ignore input unless DSR asserted
+	0x400 - Ignore input unless RI asserted
+	0x800 - Ignore input unless DCD asserted
+
+	All other bits are reserved.
 
 	Typical values are:
 
-	  0 - No flow control (default)
-	 19 - RTS/CTS flow control
-	 35 - DTR/DSR flow control
-	131 - DTR/DCD flow control
+	    0 - No flow control (default)
+	0x013 - RTS/CTS flow control
+	0x813 - RTS/CTS flow control, modem input
+	0x023 - DTR/DSR flow control
+	0x083 - DTR/DCD flow control
 
-	All other values are reserved.
-
-	For this directive to be guaranteed to work properly, it
+	For the SERIAL directive to be guaranteed to work properly, it
 	should be the first directive in the configuration file.
 
 FONT filename