linux-kernel - Re: [x86 setup 17/33] A20 handling code

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Date:	Tue, 10 Jul 2007 20:27:51 +0200 (CEST)
From:	Jan Engelhardt <jengelh@...putergmbh.de>
To:	"H. Peter Anvin" <hpa@...or.com>
cc:	linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
	andi@...stfloor.org, akpm@...ux-foundation.org
Subject: Re: [x86 setup 17/33] A20 handling code


On Jul 9 2007 19:51, H. Peter Anvin wrote:

>+		status = inb(0x64);
>+		if (status & 1) {
>+			/* Read and discard input data */
>+			io_delay();
>+			(void)inb(0x60);

Is the (void) cast needed for some obscure reason? Let's hope inb _is_ declared
as volatile. (Minus the volatile flames.

>+		} else if (!(status & 2)) {
>+			/* Buffers empty, finished! */
>+			return 0;
>+		}
>+	}
>+
>+	return -1;
>+}
>+
>+
>+#define A20_TEST_ADDR	(4*0x80)
>+#define A20_TEST_SHORT  32
>+#define A20_TEST_LONG	2097152	/* 2^21 */

Maybe...?
#define A20_TEST_LONG (1 << 21)

>+/* Quick test to see if A20 is already enabled */
>+static int a20_test_short(void)
>+{
>+	return a20_test(A20_TEST_SHORT);
>+}
>+
>+/* Longer test that actually waits for A20 to come on line; this
>+   is useful when dealing with the KBC or other slow external circuitry. */
>+static int a20_test_long(void)
>+{
>+	return a20_test(A20_TEST_LONG);
>+}

To me looks like some of these (or other functions) could return bool.



	Jan
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