m68k/mac: fix nubus slot irq disable and shutdown (c4af5da7) · Commits · e / devices / android_kernel_oneplus_sm7250

arch/m68k/include/asm/mac_via.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -257,6 +257,8 @@ extern int rbv_present,via_alt_mapping;
		extern void via_register_interrupts(void);
		extern void via_irq_enable(int);
		extern void via_irq_disable(int);
		extern void via_nubus_irq_startup(int irq);
		extern void via_nubus_irq_shutdown(int irq);
		extern void via1_irq(unsigned int irq, struct irq_desc *desc);
		extern void via1_set_head(int);
		extern int via2_scsi_drq_pending(void);

arch/m68k/mac/macints.c

+27 −0

Original line number	Diff line number	Diff line
		@@ -151,10 +151,15 @@ irqreturn_t mac_debug_handler(int, void *);

		/* #define DEBUG_MACINTS */

		static unsigned int mac_irq_startup(struct irq_data *);
		static void mac_irq_shutdown(struct irq_data *);

		static struct irq_chip mac_irq_chip = {
		.name = "mac",
		.irq_enable = mac_irq_enable,
		.irq_disable = mac_irq_disable,
		.irq_startup = mac_irq_startup,
		.irq_shutdown = mac_irq_shutdown,
		};

		void __init mac_init_IRQ(void)
		@@ -274,6 +279,28 @@ void mac_irq_disable(struct irq_data *data)
		}
		}

		static unsigned int mac_irq_startup(struct irq_data *data)
		{
		int irq = data->irq;

		if (IRQ_SRC(irq) == 7 && !oss_present)
		via_nubus_irq_startup(irq);
		else
		mac_irq_enable(data);

		return 0;
		}

		static void mac_irq_shutdown(struct irq_data *data)
		{
		int irq = data->irq;

		if (IRQ_SRC(irq) == 7 && !oss_present)
		via_nubus_irq_shutdown(irq);
		else
		mac_irq_disable(data);
		}

		static int num_debug[8];

		irqreturn_t mac_debug_handler(int irq, void *dev_id)

arch/m68k/mac/via.c

+81 −42

Original line number	Diff line number	Diff line
		@@ -63,18 +63,47 @@ static int gIER,gIFR,gBufA,gBufB;
		#define MAC_CLOCK_LOW (MAC_CLOCK_TICK&0xFF)
		#define MAC_CLOCK_HIGH (MAC_CLOCK_TICK>>8)

		/* To disable a NuBus slot on Quadras we make that slot IRQ line an output set
		* high. On RBV we just use the slot interrupt enable register. On Macs with
		* genuine VIA chips we must use nubus_disabled to keep track of disabled slot
		* interrupts. When any slot IRQ is disabled we mask the (edge triggered) CA1
		* or "SLOTS" interrupt. When no slot is disabled, we unmask the CA1 interrupt.
		* So, on genuine VIAs, having more than one NuBus IRQ can mean trouble,
		* because closing one of those drivers can mask all of the NuBus interrupts.
		* Also, since we can't mask the unregistered slot IRQs on genuine VIAs, it's
		* possible to get interrupts from cards that MacOS or the ROM has configured
		* but we have not. FWIW, "Designing Cards and Drivers for Macintosh II and
		* Macintosh SE", page 9-8, says, a slot IRQ with no driver would crash MacOS.

		/*
		* On Macs with a genuine VIA chip there is no way to mask an individual slot
		* interrupt. This limitation also seems to apply to VIA clone logic cores in
		* Quadra-like ASICs. (RBV and OSS machines don't have this limitation.)
		*
		* We used to fake it by configuring the relevent VIA pin as an output
		* (to mask the interrupt) or input (to unmask). That scheme did not work on
		* (at least) the Quadra 700. A NuBus card's /NMRQ signal is an open-collector
		* circuit (see Designing Cards and Drivers for Macintosh II and Macintosh SE,
		* p. 10-11 etc) but VIA outputs are not (see datasheet).
		*
		* Driving these outputs high must cause the VIA to source current and the
		* card to sink current when it asserts /NMRQ. Current will flow but the pin
		* voltage is uncertain and so the /NMRQ condition may still cause a transition
		* at the VIA2 CA1 input (which explains the lost interrupts). A side effect
		* is that a disabled slot IRQ can never be tested as pending or not.
		*
		* Driving these outputs low doesn't work either. All the slot /NMRQ lines are
		* (active low) OR'd together to generate the CA1 (aka "SLOTS") interrupt (see
		* The Guide To Macintosh Family Hardware, 2nd edition p. 167). If we drive a
		* disabled /NMRQ line low, the falling edge immediately triggers a CA1
		* interrupt and all slot interrupts after that will generate no transition
		* and therefore no interrupt, even after being re-enabled.
		*
		* So we make the VIA port A I/O lines inputs and use nubus_disabled to keep
		* track of their states. When any slot IRQ becomes disabled we mask the CA1
		* umbrella interrupt. Only when all slot IRQs become enabled do we unmask
		* the CA1 interrupt. It must remain enabled even when cards have no interrupt
		* handler registered. Drivers must therefore disable a slot interrupt at the
		* device before they call free_irq (like shared and autovector interrupts).
		*
		* There is also a related problem when MacOS is used to boot Linux. A network
		* card brought up by a MacOS driver may raise an interrupt while Linux boots.
		* This can be fatal since it can't be handled until the right driver loads
		* (if such a driver exists at all). Apparently related to this hardware
		* limitation, "Designing Cards and Drivers", p. 9-8, says that a slot
		* interrupt with no driver would crash MacOS (the book was written before
		* the appearance of Macs with RBV or OSS).
		*/

		static u8 nubus_disabled;

		void via_debug_dump(void);
		@@ -354,34 +383,55 @@ void __init via_nubus_init(void)
		via2[gBufB] \|= 0x02;
		}

		/* Disable all the slot interrupts (where possible). */
		/*
		* Disable the slot interrupts. On some hardware that's not possible.
		* On some hardware it's unclear what all of these I/O lines do.
		*/

		switch (macintosh_config->via_type) {
		case MAC_VIA_II:
		/* Just make the port A lines inputs. */
		switch(macintosh_config->ident) {
		case MAC_MODEL_II:
		case MAC_MODEL_IIX:
		case MAC_MODEL_IICX:
		case MAC_MODEL_SE30:
		/* The top two bits are RAM size outputs. */
		via2[vDirA] &= 0xC0;
		break;
		default:
		via2[vDirA] &= 0x80;
		}
		case MAC_VIA_QUADRA:
		pr_debug("VIA2 vDirA is 0x%02X\n", via2[vDirA]);
		break;
		case MAC_VIA_IIci:
		/* RBV. Disable all the slot interrupts. SIER works like IER. */
		via2[rSIER] = 0x7F;
		break;
		}
		}

		void via_nubus_irq_startup(int irq)
		{
		int irq_idx = IRQ_IDX(irq);

		switch (macintosh_config->via_type) {
		case MAC_VIA_II:
		case MAC_VIA_QUADRA:
		/* Disable the inactive slot interrupts by making those lines outputs. */
		if ((macintosh_config->adb_type != MAC_ADB_PB1) &&
		(macintosh_config->adb_type != MAC_ADB_PB2)) {
		via2[vBufA] \|= 0x7F;
		via2[vDirA] \|= 0x7F;
		/* Make the port A line an input. Probably redundant. */
		if (macintosh_config->via_type == MAC_VIA_II) {
		/* The top two bits are RAM size outputs. */
		via2[vDirA] &= 0xC0 \| ~(1 << irq_idx);
		} else {
		/* Allow NuBus slots 9 through F. */
		via2[vDirA] &= 0x80 \| ~(1 << irq_idx);
		}
		/* fall through */
		case MAC_VIA_IIci:
		via_irq_enable(irq);
		break;
		}
		}

		void via_nubus_irq_shutdown(int irq)
		{
		switch (macintosh_config->via_type) {
		case MAC_VIA_II:
		case MAC_VIA_QUADRA:
		/* Ensure that the umbrella CA1 interrupt remains enabled. */
		via_irq_enable(irq);
		break;
		case MAC_VIA_IIci:
		via_irq_disable(irq);
		break;
		}
		}
		@@ -507,6 +557,7 @@ void via_irq_enable(int irq) {
		} else if (irq_src == 7) {
		switch (macintosh_config->via_type) {
		case MAC_VIA_II:
		case MAC_VIA_QUADRA:
		nubus_disabled &= ~(1 << irq_idx);
		/* Enable the CA1 interrupt when no slot is disabled. */
		if (!nubus_disabled)
		@@ -518,14 +569,6 @@ void via_irq_enable(int irq) {
		*/
		via2[rSIER] = IER_SET_BIT(irq_idx);
		break;
		case MAC_VIA_QUADRA:
		/* Make the port A line an input to enable the slot irq.
		* But not on PowerBooks, that's ADB.
		*/
		if ((macintosh_config->adb_type != MAC_ADB_PB1) &&
		(macintosh_config->adb_type != MAC_ADB_PB2))
		via2[vDirA] &= ~(1 << irq_idx);
		break;
		}
		}
		}
		@@ -545,6 +588,7 @@ void via_irq_disable(int irq) {
		} else if (irq_src == 7) {
		switch (macintosh_config->via_type) {
		case MAC_VIA_II:
		case MAC_VIA_QUADRA:
		nubus_disabled \|= 1 << irq_idx;
		if (nubus_disabled)
		via2[gIER] = IER_CLR_BIT(1);
		@@ -552,11 +596,6 @@ void via_irq_disable(int irq) {
		case MAC_VIA_IIci:
		via2[rSIER] = IER_CLR_BIT(irq_idx);
		break;
		case MAC_VIA_QUADRA:
		if ((macintosh_config->adb_type != MAC_ADB_PB1) &&
		(macintosh_config->adb_type != MAC_ADB_PB2))
		via2[vDirA] \|= 1 << irq_idx;
		break;
		}
		}
		}