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 <[e-mail]>

arch/powerpc/include/asm/msi_bitmap.h

···
 void msi_bitmap_free_hwirqs(struct msi_bitmap *bmp, unsigned int offset,
 			    unsigned int num);
 void msi_bitmap_reserve_hwirq(struct msi_bitmap *bmp, unsigned int hwirq);
-int msi_bitmap_alloc_hwirqs_from_offset(struct msi_bitmap *bmp, int offset,
-					int num);
 
 int msi_bitmap_reserve_dt_hwirqs(struct msi_bitmap *bmp);
 

arch/powerpc/sysdev/fsl_msi.c

···
 		 * 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.
···
 			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;
 		}
···
 		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__);
···
 
 		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",

arch/powerpc/sysdev/fsl_msi.h

···
 
 #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 */
···
 #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 {
···
 	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];

arch/powerpc/sysdev/msi_bitmap.c

···
 #include <asm/msi_bitmap.h>
 #include <asm/setup.h>
 
-int msi_bitmap_alloc_hwirqs_from_offset(struct msi_bitmap *bmp, int offset,
-					int num)
-{
-	unsigned long flags;
-	int index;
-	int 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);
-	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;
-}
-
 int msi_bitmap_alloc_hwirqs(struct msi_bitmap *bmp, int num)
 {
-	return msi_bitmap_alloc_hwirqs_from_offset(bmp, 0, num);
+	unsigned long flags;
+	int offset, order = get_count_order(num);
+
+	spin_lock_irqsave(&bmp->lock, flags);
+	/*
+	 * 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: allocated 0x%x (2^%d) at offset 0x%x\n",
+		 num, order, offset);
+
+	return offset;
 }
 
 void msi_bitmap_free_hwirqs(struct msi_bitmap *bmp, unsigned int offset,