[PATCH] Initial generic hypertransport interrupt support
This patch implements two functions ht_create_irq and ht_destroy_irq for
use by drivers. Several other functions are implemented as helpers for
arch specific irq_chip handlers.
The driver for the card I tested this on isn't yet ready to be merged.
However this code is and hypertransport irqs are in use in a few other
places in the kernel. Not that any of this will get merged before 2.6.19
Because the ipath-ht400 is slightly out of spec this code will need to be
generalized to work there.
I think all of the powerpc uses are for a plain interrupt controller in a
chipset so support for native hypertransport devices is a little less
interesting.
However I think this is a half way decent model on how to separate arch
specific and generic helper code, and I think this is a functional model of
how to get the architecture dependencies out of the msi code.
[akpm@osdl.org: Kconfig fix]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Greg KH <greg@kroah.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/pci/htirq.c b/drivers/pci/htirq.c
new file mode 100644
index 0000000..4ba4635
--- /dev/null
+++ b/drivers/pci/htirq.c
@@ -0,0 +1,189 @@
+/*
+ * File: htirq.c
+ * Purpose: Hypertransport Interrupt Capability
+ *
+ * Copyright (C) 2006 Linux Networx
+ * Copyright (C) Eric Biederman <ebiederman@lnxi.com>
+ */
+
+#include <linux/irq.h>
+#include <linux/pci.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/gfp.h>
+
+/* Global ht irq lock.
+ *
+ * This is needed to serialize access to the data port in hypertransport
+ * irq capability.
+ *
+ * With multiple simultaneous hypertransport irq devices it might pay
+ * to make this more fine grained. But start with simple, stupid, and correct.
+ */
+static DEFINE_SPINLOCK(ht_irq_lock);
+
+struct ht_irq_cfg {
+ struct pci_dev *dev;
+ unsigned pos;
+ unsigned idx;
+};
+
+void write_ht_irq_low(unsigned int irq, u32 data)
+{
+ struct ht_irq_cfg *cfg = get_irq_data(irq);
+ unsigned long flags;
+ spin_lock_irqsave(&ht_irq_lock, flags);
+ pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx);
+ pci_write_config_dword(cfg->dev, cfg->pos + 4, data);
+ spin_unlock_irqrestore(&ht_irq_lock, flags);
+}
+
+void write_ht_irq_high(unsigned int irq, u32 data)
+{
+ struct ht_irq_cfg *cfg = get_irq_data(irq);
+ unsigned long flags;
+ spin_lock_irqsave(&ht_irq_lock, flags);
+ pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx + 1);
+ pci_write_config_dword(cfg->dev, cfg->pos + 4, data);
+ spin_unlock_irqrestore(&ht_irq_lock, flags);
+}
+
+u32 read_ht_irq_low(unsigned int irq)
+{
+ struct ht_irq_cfg *cfg = get_irq_data(irq);
+ unsigned long flags;
+ u32 data;
+ spin_lock_irqsave(&ht_irq_lock, flags);
+ pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx);
+ pci_read_config_dword(cfg->dev, cfg->pos + 4, &data);
+ spin_unlock_irqrestore(&ht_irq_lock, flags);
+ return data;
+}
+
+u32 read_ht_irq_high(unsigned int irq)
+{
+ struct ht_irq_cfg *cfg = get_irq_data(irq);
+ unsigned long flags;
+ u32 data;
+ spin_lock_irqsave(&ht_irq_lock, flags);
+ pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx + 1);
+ pci_read_config_dword(cfg->dev, cfg->pos + 4, &data);
+ spin_unlock_irqrestore(&ht_irq_lock, flags);
+ return data;
+}
+
+void mask_ht_irq(unsigned int irq)
+{
+ struct ht_irq_cfg *cfg;
+ unsigned long flags;
+ u32 data;
+
+ cfg = get_irq_data(irq);
+
+ spin_lock_irqsave(&ht_irq_lock, flags);
+ pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx);
+ pci_read_config_dword(cfg->dev, cfg->pos + 4, &data);
+ data |= 1;
+ pci_write_config_dword(cfg->dev, cfg->pos + 4, data);
+ spin_unlock_irqrestore(&ht_irq_lock, flags);
+}
+
+void unmask_ht_irq(unsigned int irq)
+{
+ struct ht_irq_cfg *cfg;
+ unsigned long flags;
+ u32 data;
+
+ cfg = get_irq_data(irq);
+
+ spin_lock_irqsave(&ht_irq_lock, flags);
+ pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx);
+ pci_read_config_dword(cfg->dev, cfg->pos + 4, &data);
+ data &= ~1;
+ pci_write_config_dword(cfg->dev, cfg->pos + 4, data);
+ spin_unlock_irqrestore(&ht_irq_lock, flags);
+}
+
+/**
+ * ht_create_irq - create an irq and attach it to a device.
+ * @dev: The hypertransport device to find the irq capability on.
+ * @idx: Which of the possible irqs to attach to.
+ *
+ * ht_create_irq is needs to be called for all hypertransport devices
+ * that generate irqs.
+ *
+ * The irq number of the new irq or a negative error value is returned.
+ */
+int ht_create_irq(struct pci_dev *dev, int idx)
+{
+ struct ht_irq_cfg *cfg;
+ unsigned long flags;
+ u32 data;
+ int max_irq;
+ int pos;
+ int irq;
+
+ pos = pci_find_capability(dev, PCI_CAP_ID_HT);
+ while (pos) {
+ u8 subtype;
+ pci_read_config_byte(dev, pos + 3, &subtype);
+ if (subtype == HT_CAPTYPE_IRQ)
+ break;
+ pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_HT);
+ }
+ if (!pos)
+ return -EINVAL;
+
+ /* Verify the idx I want to use is in range */
+ spin_lock_irqsave(&ht_irq_lock, flags);
+ pci_write_config_byte(dev, pos + 2, 1);
+ pci_read_config_dword(dev, pos + 4, &data);
+ spin_unlock_irqrestore(&ht_irq_lock, flags);
+
+ max_irq = (data >> 16) & 0xff;
+ if ( idx > max_irq)
+ return -EINVAL;
+
+ cfg = kmalloc(sizeof(*cfg), GFP_KERNEL);
+ if (!cfg)
+ return -ENOMEM;
+
+ cfg->dev = dev;
+ cfg->pos = pos;
+ cfg->idx = 0x10 + (idx * 2);
+
+ irq = create_irq();
+ if (irq < 0) {
+ kfree(cfg);
+ return -EBUSY;
+ }
+ set_irq_data(irq, cfg);
+
+ if (arch_setup_ht_irq(irq, dev) < 0) {
+ ht_destroy_irq(irq);
+ return -EBUSY;
+ }
+
+ return irq;
+}
+
+/**
+ * ht_destroy_irq - destroy an irq created with ht_create_irq
+ *
+ * This reverses ht_create_irq removing the specified irq from
+ * existence. The irq should be free before this happens.
+ */
+void ht_destroy_irq(unsigned int irq)
+{
+ struct ht_irq_cfg *cfg;
+
+ cfg = get_irq_data(irq);
+ set_irq_chip(irq, NULL);
+ set_irq_data(irq, NULL);
+ destroy_irq(irq);
+
+ kfree(cfg);
+}
+
+EXPORT_SYMBOL(ht_create_irq);
+EXPORT_SYMBOL(ht_destroy_irq);