Re: [PATCH] Making TI bridges work with kernel PCMCIA

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

>Hello!
>
>The driver for Cardbus/PCMCIA bridges (yenta_socket) doesn't initialize 
>the irqmux register of TI bridges.  In fact, the driver doesn't even 
>access that register.
>
>My experience shows that relying in the initial values of that register is
>not a good idea.  It is set to use ISA interrupts, but they don't work
>with either of two motherboards I tested the bridge with.
>
>Bridge:
>CardBus bridge: Texas Instruments PCI1410 PC card Cardbus Controller (rev 01)
>
>Fisrt system:
>Athlon 1GHz, motherboard AOpen KT-133.
>
>Second system:
>Compaq AP500, 2 x Pentium II, motherboard with Intel 440BX chipset.
>
>This patch makes the same thing as "irq_mode=0" does in the standalone
>PCMCIA driver (i82365).  It means that PCMCIA cards inserted to the socket
>have their interrupt redirected to the same PCI interrupt that is used for
>the Card Status Change (csc) notification.  I believe that's the safest
>behavior, as it avoids probing ISA interupts.
>
>Since the patch changes ti_open(), it affects all TI bridges.  This should 
>be the right thing to do according to the pcmcia-cs sources.  I'm a bit 
>surprized that the driver doesn't access those registers at all except 
>some old TI113x models.
>
>The code with TI122X_SCR_INTRTIE has been copied from pcmcia-cs without
>changes.  It should only affect two-socket bridges.
>
>The patch is against 2.4.17-rc2.

I have to use a similar workaround on pmac laptops. However, I do that
in the platform specific quirks.

Ben.

>=========================
>--- linux.orig/drivers/pcmcia/ti113x.h
>+++ linux/drivers/pcmcia/ti113x.h
>@@ -150,11 +150,27 @@
>  */
> static int ti_open(pci_socket_t *socket)
> {
>+	u32 irqmux;
>+	u8 devctl, sysctl;
> 	u8 new, reg = exca_readb(socket, I365_INTCTL);
> 
> 	new = reg & ~I365_INTR_ENA;
> 	if (new != reg)
> 		exca_writeb(socket, I365_INTCTL, new);
>+
>+	/* Disable ISA interrupt routing ... */
>+	devctl = config_readb(socket, TI113X_DEVICE_CONTROL);
>+	devctl &= ~TI113X_DCR_IMODE_MASK;
>+	config_writeb(socket, TI113X_DEVICE_CONTROL, devctl);
>+	/* ... and enable PCI routing instead */
>+	sysctl = config_readb(socket, TI113X_SYSTEM_CONTROL);
>+	irqmux = config_readl(socket, TI122X_IRQMUX);
>+	irqmux = (irqmux & ~0x0f) | 0x02; /* route INTA */
>+	if (!(sysctl & TI122X_SCR_INTRTIE)) {
>+		irqmux = (irqmux & ~0xf0) | 0x20; /* route INTB */
>+	}
>+	config_writel(socket, TI122X_IRQMUX, irqmux);
>+
> 	return 0;
> }