[PATCH] ppc64: Add driver for BPA interrupt controllers

Add support for the integrated interrupt controller on BPA
CPUs. There is one of those for each SMT thread.

The mapping of interrupt numbers to HW interrupt sources
is described in arch/ppc64/kernel/bpa_iic.h.

This version hardcodes the 'Spider' chip as the secondary
interrupt controller. That is not really generic for the
architecture, but at the moment it is the only secondary
PIC that exists.

A little more work will be needed on this as soon as
we have boards with multiple external interrupt controllers.

Signed-off-by: Arnd Bergmann <arndb@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 191 insertions, 0 deletions

diff --git a/arch/ppc64/kernel/spider-pic.c b/arch/ppc64/kernel/spider-pic.c
new file mode 100644
index 000000000000..d5c9a02fb119
--- /dev/null
+++ b/arch/ppc64/kernel/spider-pic.c
@@ -0,0 +1,191 @@
+/*
+ * External Interrupt Controller on Spider South Bridge
+ *
+ * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
+ *
+ * Author: Arnd Bergmann <arndb@de.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+
+#include <asm/pgtable.h>
+#include <asm/prom.h>
+#include <asm/io.h>
+
+#include "bpa_iic.h"
+
+/* register layout taken from Spider spec, table 7.4-4 */
+enum {
+        TIR_DEN         = 0x004, /* Detection Enable Register */
+        TIR_MSK         = 0x084, /* Mask Level Register */
+        TIR_EDC         = 0x0c0, /* Edge Detection Clear Register */
+        TIR_PNDA        = 0x100, /* Pending Register A */
+        TIR_PNDB        = 0x104, /* Pending Register B */
+        TIR_CS          = 0x144, /* Current Status Register */
+        TIR_LCSA        = 0x150, /* Level Current Status Register A */
+        TIR_LCSB        = 0x154, /* Level Current Status Register B */
+        TIR_LCSC        = 0x158, /* Level Current Status Register C */
+        TIR_LCSD        = 0x15c, /* Level Current Status Register D */
+        TIR_CFGA        = 0x200, /* Setting Register A0 */
+        TIR_CFGB        = 0x204, /* Setting Register B0 */
+                        /* 0x208 ... 0x3ff Setting Register An/Bn */
+        TIR_PPNDA       = 0x400, /* Packet Pending Register A */
+        TIR_PPNDB       = 0x404, /* Packet Pending Register B */
+        TIR_PIERA       = 0x408, /* Packet Output Error Register A */
+        TIR_PIERB       = 0x40c, /* Packet Output Error Register B */
+        TIR_PIEN        = 0x444, /* Packet Output Enable Register */
+        TIR_PIPND       = 0x454, /* Packet Output Pending Register */
+        TIRDID          = 0x484, /* Spider Device ID Register */
+        REISTIM         = 0x500, /* Reissue Command Timeout Time Setting */
+        REISTIMEN       = 0x504, /* Reissue Command Timeout Setting */
+        REISWAITEN      = 0x508, /* Reissue Wait Control*/
+};
+
+static void __iomem *spider_pics[4];
+
+static void __iomem *spider_get_pic(int irq)
+{
+        int node = irq / IIC_NODE_STRIDE;
+        irq %= IIC_NODE_STRIDE;
+
+        if (irq >= IIC_EXT_OFFSET &&
+            irq < IIC_EXT_OFFSET + IIC_NUM_EXT &&
+            spider_pics)
+                return spider_pics[node];
+        return NULL;
+}
+
+static int spider_get_nr(unsigned int irq)
+{
+        return (irq % IIC_NODE_STRIDE) - IIC_EXT_OFFSET;
+}
+
+static void __iomem *spider_get_irq_config(int irq)
+{
+        void __iomem *pic;
+        pic = spider_get_pic(irq);
+        return pic + TIR_CFGA + 8 * spider_get_nr(irq);
+}
+
+static void spider_enable_irq(unsigned int irq)
+{
+        void __iomem *cfg = spider_get_irq_config(irq);
+        irq = spider_get_nr(irq);
+
+        out_be32(cfg, in_be32(cfg) | 0x3107000eu);
+        out_be32(cfg + 4, in_be32(cfg + 4) | 0x00020000u | irq);
+}
+
+static void spider_disable_irq(unsigned int irq)
+{
+        void __iomem *cfg = spider_get_irq_config(irq);
+        irq = spider_get_nr(irq);
+
+        out_be32(cfg, in_be32(cfg) & ~0x30000000u);
+}
+
+static unsigned int spider_startup_irq(unsigned int irq)
+{
+        spider_enable_irq(irq);
+        return 0;
+}
+
+static void spider_shutdown_irq(unsigned int irq)
+{
+        spider_disable_irq(irq);
+}
+
+static void spider_end_irq(unsigned int irq)
+{
+        spider_enable_irq(irq);
+}
+
+static void spider_ack_irq(unsigned int irq)
+{
+        spider_disable_irq(irq);
+        iic_local_enable();
+}
+
+static struct hw_interrupt_type spider_pic = {
+        .typename = " SPIDER   ",
+        .startup = spider_startup_irq,
+        .shutdown = spider_shutdown_irq,
+        .enable = spider_enable_irq,
+        .disable = spider_disable_irq,
+        .ack = spider_ack_irq,
+        .end = spider_end_irq,
+};
+
+
+int spider_get_irq(unsigned long int_pending)
+{
+        void __iomem *regs = spider_get_pic(int_pending);
+        unsigned long cs;
+        int irq;
+
+        cs = in_be32(regs + TIR_CS);
+
+        irq = cs >> 24;
+        if (irq != 63)
+                return irq;
+
+        return -1;
+}
+ 
+void spider_init_IRQ(void)
+{
+        int node;
+        struct device_node *dn;
+        unsigned int *property;
+        long spiderpic;
+        int n;
+
+/* FIXME: detect multiple PICs as soon as the device tree has them */
+        for (node = 0; node < 1; node++) {
+                dn = of_find_node_by_path("/");
+                n = prom_n_addr_cells(dn);
+                property = (unsigned int *) get_property(dn,
+                                "platform-spider-pic", NULL);
+
+                if (!property)
+                        continue;
+                for (spiderpic = 0; n > 0; --n)
+                        spiderpic = (spiderpic << 32) + *property++;
+                printk(KERN_DEBUG "SPIDER addr: %lx\n", spiderpic);
+                spider_pics[node] = __ioremap(spiderpic, 0x800, _PAGE_NO_CACHE);
+                for (n = 0; n < IIC_NUM_EXT; n++) {
+                        int irq = n + IIC_EXT_OFFSET + node * IIC_NODE_STRIDE;
+                        get_irq_desc(irq)->handler = &spider_pic;
+
+                /* do not mask any interrupts because of level */
+                out_be32(spider_pics[node] + TIR_MSK, 0x0);
+                
+                /* disable edge detection clear */
+                /* out_be32(spider_pics[node] + TIR_EDC, 0x0); */
+                
+                /* enable interrupt packets to be output */
+                out_be32(spider_pics[node] + TIR_PIEN,
+                        in_be32(spider_pics[node] + TIR_PIEN) | 0x1);
+                
+                /* Enable the interrupt detection enable bit. Do this last! */
+                out_be32(spider_pics[node] + TIR_DEN,
+                        in_be32(spider_pics[node] +TIR_DEN) | 0x1);
+
+                }
+        }
+}