From 012d53b0453ac7a5ec03fb802434fe64e6f85bf5 Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin" <hpa@zytor.com>
Date: Mon, 9 Jun 2008 16:16:31 -0700
Subject: [PATCH] PXELINUX: Enable idle calls on select platforms

Enable idle calls on select platforms, based on device ID.
In particular, certain Broadcom chips need them to avoid FIFO stalls.
---
 core/comboot.inc  | 10 ++++------
 core/conio.inc    |  6 ++++--
 core/pxelinux.asm | 27 +++++++++++++++++----------
 3 files changed, 25 insertions(+), 18 deletions(-)

diff --git a/core/comboot.inc b/core/comboot.inc
index df9bb00..b843372 100644
--- a/core/comboot.inc
+++ b/core/comboot.inc
@@ -971,14 +971,12 @@ zero_string	db 0			; Empty, null-terminated string
 
 ;
 ; This is the feature flag array for INT 22h AX=0015h
+;
+; Note: PXELINUX clears the idle is noop flag if appropriate
+; in pxe_detect_nic_type
+;
 feature_flags:
-%if IS_PXELINUX
-		db 1			; Have local boot, idle not noop
-%elif IS_ISOLINUX
 		db 3			; Have local boot, idle is noop
-%else
-		db 2			; No local boot, idle is noop
-%endif
 feature_flags_len equ ($-feature_flags)
 
 err_notdos	db ': attempted DOS system call', CR, LF, 0
diff --git a/core/conio.inc b/core/conio.inc
index 4700596..0dc3f1d 100644
--- a/core/conio.inc
+++ b/core/conio.inc
@@ -282,6 +282,7 @@ write_serial_str:
 ;
 pollchar:
 		pushad
+		DO_IDLE
 		mov ah,11h		; Poll keyboard
 		int 16h
 		jnz .done		; Keyboard response
@@ -306,7 +307,6 @@ pollchar:
 ; getchar: Read a character from keyboard or serial port
 ;
 getchar:
-		RESET_IDLE
 .again:
 		DO_IDLE
 		mov ah,11h		; Poll keyboard
@@ -339,7 +339,9 @@ getchar:
 		jz .func_key
 		mov bx,KbdMap		; Convert character sets
 		xlatb
-.func_key:	ret
+.func_key:
+		RESET_IDLE		; Character received
+		ret
 
 %ifdef DEBUG_TRACERS
 ;
diff --git a/core/pxelinux.asm b/core/pxelinux.asm
index fccf82f..9e2d2fb 100644
--- a/core/pxelinux.asm
+++ b/core/pxelinux.asm
@@ -54,12 +54,7 @@ TFTP_BLOCKSIZE	equ (1 << TFTP_BLOCKSIZE_LG2)
 SECTOR_SHIFT	equ TFTP_BLOCKSIZE_LG2
 SECTOR_SIZE	equ TFTP_BLOCKSIZE
 
-;
-; This is what we need to do when idle
-; *** This is disabled because some PXE stacks wait for unacceptably
-; *** long if there are no packets receivable.
-
-%define HAVE_IDLE 0			; idle is not a noop
+%define HAVE_IDLE 1			; idle is not a noop
 
 %if HAVE_IDLE
 %macro	RESET_IDLE 0
@@ -652,6 +647,12 @@ udp_init:
 %include "cpuinit.inc"
 
 ;
+; Detect NIC type and initialize the idle mechanism
+;
+		call pxe_detect_nic_type
+		RESET_IDLE
+
+;
 ; Now we're all set to start with our *real* business.	First load the
 ; configuration file (if any) and parse it.
 ;
@@ -1091,7 +1092,6 @@ searchdir:
 		mov bx,[bx]
 		push bx			; [bp-8]  - TID (local port no)
 
-		mov [pxe_udp_write_pkt.status],byte 0
 		mov [pxe_udp_write_pkt.sip],eax
 		; Now figure out the gateway
 		xor eax,[MyIP]
@@ -1127,7 +1127,6 @@ searchdir:
 
 .pkt_loop:	mov bx,[bp-8]		; TID
 		mov di,packet_buf
-		mov word [pxe_udp_read_pkt.status],0
 		mov [pxe_udp_read_pkt.buffer],di
 		mov [pxe_udp_read_pkt.buffer+2],ds
 		mov word [pxe_udp_read_pkt.buffersize],packet_buf_size
@@ -1691,6 +1690,9 @@ pxenv:
 		mov [cs:PXEStack+2],ss
 		lss sp,[cs:InitStack]
 %endif
+		; Pre-clear the Status field
+		mov word [es:di],cs
+
 		; This works either for the PXENV+ or the !PXE calling
 		; convention, as long as we ignore CF (which is redundant
 		; with AX anyway.)
@@ -2621,6 +2623,9 @@ genipopt:
 ; passed since the last poll, and reset this when a character is
 ; received (RESET_IDLE).
 ;
+; Note: we only do this if pxe_detect_nic_type has cleared the
+; "idle is noop" bit in feature_flags.
+;
 %if HAVE_IDLE
 
 reset_idle:
@@ -2631,13 +2636,15 @@ reset_idle:
 		ret
 
 check_for_arp:
+		test byte [cs:feature_flags],2
+		jnz .ret
 		push ax
 		mov ax,[cs:BIOS_timer]
 		sub ax,[cs:IdleTimer]
 		cmp ax,4
 		pop ax
 		jae .need_poll
-		ret
+.ret:		ret
 .need_poll:	pushad
 		push ds
 		push es
@@ -2645,7 +2652,6 @@ check_for_arp:
 		mov ds,ax
 		mov es,ax
 		mov di,packet_buf
-		mov [pxe_udp_read_pkt.status],al	; 0
 		mov [pxe_udp_read_pkt.buffer],di
 		mov [pxe_udp_read_pkt.buffer+2],ds
 		mov word [pxe_udp_read_pkt.buffersize],packet_buf_size
@@ -2684,6 +2690,7 @@ writestr	equ cwritestr
 %include "strcpy.inc"		; strcpy()
 %include "rawcon.inc"		; Console I/O w/o using the console functions
 %include "dnsresolv.inc"	; DNS resolver
+%include "pxeidle.inc"		; Idle mechanism
 %include "adv.inc"		; Auxillary Data Vector
 
 ; -----------------------------------------------------------------------------
-- 
2.7.4