[PATCH] genirq: msi: implement helper functions read_msi_msg and write_msi_msg

In support of this I also add a struct msi_msg that captures the the two
address and one data field ina typical msi message, and I remember the pos and
if the address is 64bit in struct msi_desc.

This makes the code a little more readable and easier to maintain, and paves
the way to further simplfications.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rajesh Shah <rajesh.shah@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 104 insertions, 106 deletions

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 75d1c0dacffa..cca6cb3ccdac 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -87,63 +87,100 @@ static void msi_set_mask_bit(unsigned int vector, int flag)
         }
 }
 
-#ifdef CONFIG_SMP
-static void set_msi_affinity(unsigned int vector, cpumask_t cpu_mask)
+static void read_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
 {
-        struct msi_desc *entry;
-        u32 address_hi, address_lo;
-        unsigned int irq = vector;
-        unsigned int dest_cpu = first_cpu(cpu_mask);
-
-        entry = (struct msi_desc *)msi_desc[vector];
-        if (!entry || !entry->dev)
-                return;
+        switch(entry->msi_attrib.type) {
+        case PCI_CAP_ID_MSI:
+        {
+                struct pci_dev *dev = entry->dev;
+                int pos = entry->msi_attrib.pos;
+                u16 data;
+
+                pci_read_config_dword(dev, msi_lower_address_reg(pos),
+                                        &msg->address_lo);
+                if (entry->msi_attrib.is_64) {
+                        pci_read_config_dword(dev, msi_upper_address_reg(pos),
+                                                &msg->address_hi);
+                        pci_read_config_word(dev, msi_data_reg(pos, 1), &data);
+                } else {
+                        msg->address_hi = 0;
+                        pci_read_config_word(dev, msi_data_reg(pos, 1), &data);
+                }
+                msg->data = data;
+                break;
+        }
+        case PCI_CAP_ID_MSIX:
+        {
+                void __iomem *base;
+                base = entry->mask_base +
+                        entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
+
+                msg->address_lo = readl(base + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
+                msg->address_hi = readl(base + PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
+                msg->data = readl(base + PCI_MSIX_ENTRY_DATA_OFFSET);
+                break;
+        }
+        default:
+                BUG();
+        }
+}
 
+static void write_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
+{
         switch (entry->msi_attrib.type) {
         case PCI_CAP_ID_MSI:
         {
-                int pos = pci_find_capability(entry->dev, PCI_CAP_ID_MSI);
-
-                if (!pos)
-                        return;
-
-                pci_read_config_dword(entry->dev, msi_upper_address_reg(pos),
-                        &address_hi);
-                pci_read_config_dword(entry->dev, msi_lower_address_reg(pos),
-                        &address_lo);
-
-                msi_ops->target(vector, dest_cpu, &address_hi, &address_lo);
-
-                pci_write_config_dword(entry->dev, msi_upper_address_reg(pos),
-                        address_hi);
-                pci_write_config_dword(entry->dev, msi_lower_address_reg(pos),
-                        address_lo);
-                set_native_irq_info(irq, cpu_mask);
+                struct pci_dev *dev = entry->dev;
+                int pos = entry->msi_attrib.pos;
+
+                pci_write_config_dword(dev, msi_lower_address_reg(pos),
+                                        msg->address_lo);
+                if (entry->msi_attrib.is_64) {
+                        pci_write_config_dword(dev, msi_upper_address_reg(pos),
+                                                msg->address_hi);
+                        pci_write_config_word(dev, msi_data_reg(pos, 1),
+                                                msg->data);
+                } else {
+                        pci_write_config_word(dev, msi_data_reg(pos, 0),
+                                                msg->data);
+                }
                 break;
         }
         case PCI_CAP_ID_MSIX:
         {
-                int offset_hi =
-                        entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +
-                                PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET;
-                int offset_lo =
-                        entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +
-                                PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET;
-
-                address_hi = readl(entry->mask_base + offset_hi);
-                address_lo = readl(entry->mask_base + offset_lo);
-
-                msi_ops->target(vector, dest_cpu, &address_hi, &address_lo);
-
-                writel(address_hi, entry->mask_base + offset_hi);
-                writel(address_lo, entry->mask_base + offset_lo);
-                set_native_irq_info(irq, cpu_mask);
+                void __iomem *base;
+                base = entry->mask_base +
+                        entry->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
+
+                writel(msg->address_lo,
+                        base + PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
+                writel(msg->address_hi,
+                        base + PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
+                writel(msg->data, base + PCI_MSIX_ENTRY_DATA_OFFSET);
                 break;
         }
         default:
-                break;
+                BUG();
         }
 }
+
+#ifdef CONFIG_SMP
+static void set_msi_affinity(unsigned int vector, cpumask_t cpu_mask)
+{
+        struct msi_desc *entry;
+        struct msi_msg msg;
+        unsigned int irq = vector;
+        unsigned int dest_cpu = first_cpu(cpu_mask);
+
+        entry = (struct msi_desc *)msi_desc[vector];
+        if (!entry || !entry->dev)
+                return;
+
+        read_msi_msg(entry, &msg);
+        msi_ops->target(vector, dest_cpu, &msg.address_hi, &msg.address_lo);
+        write_msi_msg(entry, &msg);
+        set_native_irq_info(irq, cpu_mask);
+}
 #else
 #define set_msi_affinity NULL
 #endif /* CONFIG_SMP */
@@ -606,23 +643,10 @@ int pci_save_msix_state(struct pci_dev *dev)
 
         vector = head = dev->irq;
         while (head != tail) {
-                int j;
-                void __iomem *base;
                 struct msi_desc *entry;
 
                 entry = msi_desc[vector];
-                base = entry->mask_base;
-                j = entry->msi_attrib.entry_nr;
-
-                entry->address_lo_save =
-                        readl(base + j * PCI_MSIX_ENTRY_SIZE +
-                              PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
-                entry->address_hi_save =
-                        readl(base + j * PCI_MSIX_ENTRY_SIZE +
-                              PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
-                entry->data_save =
-                        readl(base + j * PCI_MSIX_ENTRY_SIZE +
-                              PCI_MSIX_ENTRY_DATA_OFFSET);
+                read_msi_msg(entry, &entry->msg_save);
 
                 tail = msi_desc[vector]->link.tail;
                 vector = tail;
@@ -639,8 +663,6 @@ void pci_restore_msix_state(struct pci_dev *dev)
         u16 save;
         int pos;
         int vector, head, tail = 0;
-        void __iomem *base;
-        int j;
         struct msi_desc *entry;
         int temp;
         struct pci_cap_saved_state *save_state;
@@ -663,18 +685,7 @@ void pci_restore_msix_state(struct pci_dev *dev)
         vector = head = dev->irq;
         while (head != tail) {
                 entry = msi_desc[vector];
-                base = entry->mask_base;
-                j = entry->msi_attrib.entry_nr;
-
-                writel(entry->address_lo_save,
-                        base + j * PCI_MSIX_ENTRY_SIZE +
-                        PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
-                writel(entry->address_hi_save,
-                        base + j * PCI_MSIX_ENTRY_SIZE +
-                        PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
-                writel(entry->data_save,
-                        base + j * PCI_MSIX_ENTRY_SIZE +
-                        PCI_MSIX_ENTRY_DATA_OFFSET);
+                write_msi_msg(entry, &entry->msg_save);
 
                 tail = msi_desc[vector]->link.tail;
                 vector = tail;
@@ -689,29 +700,19 @@ void pci_restore_msix_state(struct pci_dev *dev)
 static int msi_register_init(struct pci_dev *dev, struct msi_desc *entry)
 {
         int status;
-        u32 address_hi;
-        u32 address_lo;
-        u32 data;
+        struct msi_msg msg;
         int pos, vector = dev->irq;
         u16 control;
 
-        pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
+        pos = entry->msi_attrib.pos;
         pci_read_config_word(dev, msi_control_reg(pos), &control);
 
         /* Configure MSI capability structure */
-        status = msi_ops->setup(dev, vector, &address_hi, &address_lo, &data);
+        status = msi_ops->setup(dev, vector, &msg.address_hi, &msg.address_lo, &msg.data);
         if (status < 0)
                 return status;
 
-        pci_write_config_dword(dev, msi_lower_address_reg(pos), address_lo);
-        if (is_64bit_address(control)) {
-                pci_write_config_dword(dev,
-                        msi_upper_address_reg(pos), address_hi);
-                pci_write_config_word(dev,
-                        msi_data_reg(pos, 1), data);
-        } else
-                pci_write_config_word(dev,
-                        msi_data_reg(pos, 0), data);
+        write_msi_msg(entry, &msg);
         if (entry->msi_attrib.maskbit) {
                 unsigned int maskbits, temp;
                 /* All MSIs are unmasked by default, Mask them all */
@@ -761,9 +762,11 @@ static int msi_capability_init(struct pci_dev *dev)
         entry->link.tail = vector;
         entry->msi_attrib.type = PCI_CAP_ID_MSI;
         entry->msi_attrib.state = 0;                    /* Mark it not active */
+        entry->msi_attrib.is_64 = is_64bit_address(control);
         entry->msi_attrib.entry_nr = 0;
         entry->msi_attrib.maskbit = is_mask_bit_support(control);
         entry->msi_attrib.default_vector = dev->irq;    /* Save IOAPIC IRQ */
+        entry->msi_attrib.pos = pos;
         dev->irq = vector;
         entry->dev = dev;
         if (is_mask_bit_support(control)) {
@@ -801,9 +804,7 @@ static int msix_capability_init(struct pci_dev *dev,
                                 struct msix_entry *entries, int nvec)
 {
         struct msi_desc *head = NULL, *tail = NULL, *entry = NULL;
-        u32 address_hi;
-        u32 address_lo;
-        u32 data;
+        struct msi_msg msg;
         int status;
         int vector, pos, i, j, nr_entries, temp = 0;
         unsigned long phys_addr;
@@ -840,9 +841,11 @@ static int msix_capability_init(struct pci_dev *dev,
                 entries[i].vector = vector;
                 entry->msi_attrib.type = PCI_CAP_ID_MSIX;
                 entry->msi_attrib.state = 0;            /* Mark it not active */
+                entry->msi_attrib.is_64 = 1;
                 entry->msi_attrib.entry_nr = j;
                 entry->msi_attrib.maskbit = 1;
                 entry->msi_attrib.default_vector = dev->irq;
+                entry->msi_attrib.pos = pos;
                 entry->dev = dev;
                 entry->mask_base = base;
                 if (!head) {
@@ -861,21 +864,13 @@ static int msix_capability_init(struct pci_dev *dev,
                 irq_handler_init(PCI_CAP_ID_MSIX, vector, 1);
                 /* Configure MSI-X capability structure */
                 status = msi_ops->setup(dev, vector,
-                                        &address_hi,
-                                        &address_lo,
-                                        &data);
+                                        &msg.address_hi,
+                                        &msg.address_lo,
+                                        &msg.data);
                 if (status < 0)
                         break;
 
-                writel(address_lo,
-                        base + j * PCI_MSIX_ENTRY_SIZE +
-                        PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET);
-                writel(address_hi,
-                        base + j * PCI_MSIX_ENTRY_SIZE +
-                        PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET);
-                writel(data,
-                        base + j * PCI_MSIX_ENTRY_SIZE +
-                        PCI_MSIX_ENTRY_DATA_OFFSET);
+                write_msi_msg(entry, &msg);
                 attach_msi_entry(entry, vector);
         }
         if (i != nvec) {
diff --git a/drivers/pci/msi.h b/drivers/pci/msi.h
index 9b31d4cbbce4..62f61b61d2c9 100644
--- a/drivers/pci/msi.h
+++ b/drivers/pci/msi.h
@@ -130,10 +130,10 @@ struct msi_desc {
                 __u8    type    : 5;    /* {0: unused, 5h:MSI, 11h:MSI-X} */
                 __u8    maskbit : 1;    /* mask-pending bit supported ?   */
                 __u8    state   : 1;    /* {0: free, 1: busy}             */
-                __u8    reserved: 1;    /* reserved                       */
+                __u8    is_64   : 1;    /* Address size: 0=32bit 1=64bit  */
                 __u8    entry_nr;       /* specific enabled entry         */
                 __u8    default_vector; /* default pre-assigned vector    */
-                __u8    unused;         /* formerly unused destination cpu*/
+                __u8    pos;            /* Location of the msi capability */
         }msi_attrib;
 
         struct {
@@ -146,10 +146,7 @@ struct msi_desc {
 
 #ifdef CONFIG_PM
         /* PM save area for MSIX address/data */
-
-        u32     address_hi_save;
-        u32     address_lo_save;
-        u32     data_save;
+        struct msi_msg msg_save;
 #endif
 };
 
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 4431ce4e1e6f..b9bb6c46e056 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -595,6 +595,12 @@ struct msix_entry {
         u16     entry;  /* driver uses to specify entry, OS writes */
 };
 
+struct msi_msg {
+        u32     address_lo;     /* low 32 bits of msi message address */
+        u32     address_hi;     /* high 32 bits of msi message address */
+        u32     data;           /* 16 bits of msi message data */
+};
+
 #ifndef CONFIG_PCI_MSI
 static inline void pci_scan_msi_device(struct pci_dev *dev) {}
 static inline int pci_enable_msi(struct pci_dev *dev) {return -1;}