[ARM] iop13xx: msi support

Enable devices to signal interrupts via PCI memory cycles.

rev6:
* fix enable/disable typo, Michael Ellerman

rev5:
* fix up ack, enable, and disable for iop13xx_msi_chip

rev4:
* move smp compile fix to separate patch
* use dynamic_irq_init in create_irq()
* hookup mask/unmask routines in iop13xx_msi_chip

rev3:
* change msi.c to use linux/smp.h instead of asm/smp.h
* call dynamic_irq_cleanup at destroy_irq time

rev2:
* destroy_irq did not take the full 128 bits of msi_irq_in_use into account
* added missing '&' for calls to test_and_set_bit and clear_bit

[ebiederm@xmission.com: review comments/suggestions]
[dan.j.williams@intel.com: cleanups/forward port to 2.6-git]
Signed-off-by: Daniel Wolstenholme <daniel.e.wolstenholme@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 194 insertions, 0 deletions

diff --git a/arch/arm/mach-iop13xx/msi.c b/arch/arm/mach-iop13xx/msi.c
new file mode 100644
index 00000000000..2d236930222
--- /dev/null
+++ b/arch/arm/mach-iop13xx/msi.c
@@ -0,0 +1,194 @@
+/*
+ * arch/arm/mach-iop13xx/msi.c
+ *
+ * PCI MSI support for the iop13xx processor
+ *
+ * Copyright (c) 2006, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ */
+#include <linux/pci.h>
+#include <linux/msi.h>
+#include <asm/mach/irq.h>
+#include <asm/irq.h>
+
+
+#define IOP13XX_NUM_MSI_IRQS 128
+static DECLARE_BITMAP(msi_irq_in_use, IOP13XX_NUM_MSI_IRQS);
+
+/* IMIPR0 CP6 R8 Page 1
+ */
+static inline u32 read_imipr_0(void)
+{
+	u32 val;
+	asm volatile("mrc p6, 0, %0, c8, c1, 0":"=r" (val));
+	return val;
+}
+static inline void write_imipr_0(u32 val)
+{
+	asm volatile("mcr p6, 0, %0, c8, c1, 0"::"r" (val));
+}
+
+/* IMIPR1 CP6 R9 Page 1
+ */
+static inline u32 read_imipr_1(void)
+{
+	u32 val;
+	asm volatile("mrc p6, 0, %0, c9, c1, 0":"=r" (val));
+	return val;
+}
+static inline void write_imipr_1(u32 val)
+{
+	asm volatile("mcr p6, 0, %0, c9, c1, 0"::"r" (val));
+}
+
+/* IMIPR2 CP6 R10 Page 1
+ */
+static inline u32 read_imipr_2(void)
+{
+	u32 val;
+	asm volatile("mrc p6, 0, %0, c10, c1, 0":"=r" (val));
+	return val;
+}
+static inline void write_imipr_2(u32 val)
+{
+	asm volatile("mcr p6, 0, %0, c10, c1, 0"::"r" (val));
+}
+
+/* IMIPR3 CP6 R11 Page 1
+ */
+static inline u32 read_imipr_3(void)
+{
+	u32 val;
+	asm volatile("mrc p6, 0, %0, c11, c1, 0":"=r" (val));
+	return val;
+}
+static inline void write_imipr_3(u32 val)
+{
+	asm volatile("mcr p6, 0, %0, c11, c1, 0"::"r" (val));
+}
+
+static u32 (*read_imipr[])(void) = {
+	read_imipr_0,
+	read_imipr_1,
+	read_imipr_2,
+	read_imipr_3,
+};
+
+static void (*write_imipr[])(u32) = {
+	write_imipr_0,
+	write_imipr_1,
+	write_imipr_2,
+	write_imipr_3,
+};
+
+static void iop13xx_msi_handler(unsigned int irq, struct irq_desc *desc)
+{
+	int i, j;
+	unsigned long status;
+
+	/* read IMIPR registers and find any active interrupts,
+	 * then call ISR for each active interrupt
+	 */
+	for (i = 0; i < ARRAY_SIZE(read_imipr); i++) {
+		status = (read_imipr[i])();
+		if (!status)
+			continue;
+
+		do {
+			j = find_first_bit(&status, 32);
+			(write_imipr[i])(1 << j); /* write back to clear bit */
+			desc = irq_desc + IRQ_IOP13XX_MSI_0 + j + (32*i);
+			desc_handle_irq(IRQ_IOP13XX_MSI_0 + j + (32*i),	desc);
+			status = (read_imipr[i])();
+		} while (status);
+	}
+}
+
+void __init iop13xx_msi_init(void)
+{
+	set_irq_chained_handler(IRQ_IOP13XX_INBD_MSI, iop13xx_msi_handler);
+}
+
+/*
+ * Dynamic irq allocate and deallocation
+ */
+int create_irq(void)
+{
+	int irq, pos;
+
+again:
+	pos = find_first_zero_bit(msi_irq_in_use, IOP13XX_NUM_MSI_IRQS);
+	irq = IRQ_IOP13XX_MSI_0 + pos;
+	if (irq > NR_IRQS)
+		return -ENOSPC;
+	/* test_and_set_bit operates on 32-bits at a time */
+	if (test_and_set_bit(pos, msi_irq_in_use))
+		goto again;
+
+	dynamic_irq_init(irq);
+
+	return irq;
+}
+
+void destroy_irq(unsigned int irq)
+{
+	int pos = irq - IRQ_IOP13XX_MSI_0;
+
+	dynamic_irq_cleanup(irq);
+
+	clear_bit(pos, msi_irq_in_use);
+}
+
+void arch_teardown_msi_irq(unsigned int irq)
+{
+	destroy_irq(irq);
+}
+
+static void iop13xx_msi_nop(unsigned int irq)
+{
+	return;
+}
+
+static struct irq_chip iop13xx_msi_chip = {
+	.name = "PCI-MSI",
+	.ack = iop13xx_msi_nop,
+	.enable = unmask_msi_irq,
+	.disable = mask_msi_irq,
+	.mask = mask_msi_irq,
+	.unmask = unmask_msi_irq,
+};
+
+int arch_setup_msi_irq(struct pci_dev *pdev, struct msi_desc *desc)
+{
+	int id, irq = create_irq();
+	struct msi_msg msg;
+
+	if (irq < 0)
+		return irq;
+
+	set_irq_msi(irq, desc);
+
+	msg.address_hi = 0x0;
+	msg.address_lo = IOP13XX_MU_MIMR_PCI;
+
+	id = iop13xx_cpu_id();
+	msg.data = (id << IOP13XX_MU_MIMR_CORE_SELECT) | (irq & 0x7f);
+
+	write_msi_msg(irq, &msg);
+	set_irq_chip_and_handler(irq, &iop13xx_msi_chip, handle_simple_irq);
+
+	return irq;
+}