Revert "powerpc/fsl_msi: spread msi ints across different MSIRs"

This reverts commit c822e73731fce3b49a4887140878d084d8a44c08.

This commit conflicted with a bitmap allocator change that partially
accomplishes the same thing, but which does so more correctly.  Revert
this one until it can be respun on top of the correct change.

Signed-off-by: Scott Wood <scottwood@freescale.com>

3 files changed, 11 insertions, 50 deletions

diff --git a/arch/powerpc/sysdev/fsl_msi.c b/arch/powerpc/sysdev/fsl_msi.c
index 37254eff7324..e2ee226464f8 100644
--- a/arch/powerpc/sysdev/fsl_msi.c
+++ b/arch/powerpc/sysdev/fsl_msi.c
@@ -213,8 +213,6 @@ static int fsl_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
                  * available interrupt.
                  */
                 list_for_each_entry(msi_data, &msi_head, list) {
-                        int off;
-
                         /*
                          * If the PCI node has an fsl,msi property, then we
                          * restrict our search to the corresponding MSI node.
@@ -226,28 +224,7 @@ static int fsl_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
                         if (phandle && (phandle != msi_data->phandle))
                                 continue;
 
-                        /*
-                         * Allocate the msi message so that it fits on distinct
-                         * MSIR registers. Obviously, since MSIR registers are
-                         * limited they will overlap at one point.
-                         *
-                         * Due to the format of the newly introduced MSIIR1 in
-                         * mpic 4.3, consecutive msi message values map to
-                         * distinct MSIRs, thus distinct msi irq cascades, so
-                         * nothing special needs to be done in this case.
-                         * On older mpic versions the chose distinct SRS
-                         * values by aligning the msi message value to the
-                         * SRS field shift.
-                         */
-                        if (msi_data->feature & FSL_PIC_FTR_MPIC_4_3) {
-                                off = 0;
-                        } else {
-                                off = atomic_inc_return(&msi_data->msi_alloc_cnt) %
-                                        msi_data->msir_num;
-                                off <<= msi_data->srs_shift;
-                        }
-                        hwirq = msi_bitmap_alloc_hwirqs_from_offset(
-                                                &msi_data->bitmap, off, 1);
+                        hwirq = msi_bitmap_alloc_hwirqs(&msi_data->bitmap, 1);
                         if (hwirq >= 0)
                                 break;
                 }
@@ -487,17 +464,12 @@ static int fsl_of_msi_probe(struct platform_device *dev)
                 goto error_out;
         }
 
-        atomic_set(&msi->msi_alloc_cnt, -1);
-
         p = of_get_property(dev->dev.of_node, "msi-available-ranges", &len);
 
         if (of_device_is_compatible(dev->dev.of_node, "fsl,mpic-msi-v4.3") ||
             of_device_is_compatible(dev->dev.of_node, "fsl,vmpic-msi-v4.3")) {
                 msi->srs_shift = MSIIR1_SRS_SHIFT;
                 msi->ibs_shift = MSIIR1_IBS_SHIFT;
-                msi->msir_num = NR_MSI_REG_MSIIR1;
-                msi->feature |= FSL_PIC_FTR_MPIC_4_3;
-
                 if (p)
                         dev_warn(&dev->dev, "%s: dose not support msi-available-ranges property\n",
                                 __func__);
@@ -515,7 +487,6 @@ static int fsl_of_msi_probe(struct platform_device *dev)
 
                 msi->srs_shift = MSIIR_SRS_SHIFT;
                 msi->ibs_shift = MSIIR_IBS_SHIFT;
-                msi->msir_num = NR_MSI_REG_MSIIR;
 
                 if (p && len % (2 * sizeof(u32)) != 0) {
                         dev_err(&dev->dev, "%s: Malformed msi-available-ranges property\n",
diff --git a/arch/powerpc/sysdev/fsl_msi.h b/arch/powerpc/sysdev/fsl_msi.h
index 50ec4b04c732..420cfcbdac01 100644
--- a/arch/powerpc/sysdev/fsl_msi.h
+++ b/arch/powerpc/sysdev/fsl_msi.h
@@ -15,7 +15,6 @@
 
 #include <linux/of.h>
 #include <asm/msi_bitmap.h>
-#include <asm/atomic.h>
 
 #define NR_MSI_REG_MSIIR        8  /* MSIIR can index 8 MSI registers */
 #define NR_MSI_REG_MSIIR1       16 /* MSIIR1 can index 16 MSI registers */
@@ -28,8 +27,6 @@
 #define FSL_PIC_IP_IPIC   0x00000002
 #define FSL_PIC_IP_VMPIC  0x00000003
 
-#define FSL_PIC_FTR_MPIC_4_3 0x00000010
-
 struct fsl_msi_cascade_data;
 
 struct fsl_msi {
@@ -40,8 +37,6 @@ struct fsl_msi {
         u32 msiir_offset; /* Offset of MSIIR, relative to start of CCSR */
         u32 ibs_shift; /* Shift of interrupt bit select */
         u32 srs_shift; /* Shift of the shared interrupt register select */
-        u32 msir_num; /* Number of available MSIR regs */
-        atomic_t msi_alloc_cnt; /* Counter for MSI hwirq allocations */
         void __iomem *msi_regs;
         u32 feature;
         struct fsl_msi_cascade_data *cascade_array[NR_MSI_REG_MAX];
diff --git a/arch/powerpc/sysdev/msi_bitmap.c b/arch/powerpc/sysdev/msi_bitmap.c
index 8b7d8fc2b120..2ff630267e9e 100644
--- a/arch/powerpc/sysdev/msi_bitmap.c
+++ b/arch/powerpc/sysdev/msi_bitmap.c
@@ -14,28 +14,23 @@
 #include <asm/msi_bitmap.h>
 #include <asm/setup.h>
 
-int msi_bitmap_alloc_hwirqs_from_offset(struct msi_bitmap *bmp, int offset,
-                                        int num)
+int msi_bitmap_alloc_hwirqs(struct msi_bitmap *bmp, int num)
 {
         unsigned long flags;
-        int index;
-        int order = get_count_order(num);
+        int offset, order = get_count_order(num);
 
         spin_lock_irqsave(&bmp->lock, flags);
-        index = bitmap_find_next_zero_area(bmp->bitmap, bmp->irq_count,
-                                           offset, num, (1 << order) - 1);
-        bitmap_set(bmp->bitmap, index, num);
+        /*
+         * This is fast, but stricter than we need. We might want to add
+         * a fallback routine which does a linear search with no alignment.
+         */
+        offset = bitmap_find_free_region(bmp->bitmap, bmp->irq_count, order);
         spin_unlock_irqrestore(&bmp->lock, flags);
 
-        pr_debug("msi_bitmap: found %d free bits starting from offset %d at index %d\n",
-                 num, offset, index);
-
-        return index;
-}
+        pr_debug("msi_bitmap: allocated 0x%x (2^%d) at offset 0x%x\n",
+                 num, order, offset);
 
-int msi_bitmap_alloc_hwirqs(struct msi_bitmap *bmp, int num)
-{
-        return msi_bitmap_alloc_hwirqs_from_offset(bmp, 0, num);
+        return offset;
 }
 
 void msi_bitmap_free_hwirqs(struct msi_bitmap *bmp, unsigned int offset,