drivers/iommu/amd: Clean up iommu_pc_get_set_reg()

Clean up coding style and fix a bug in the 64-bit register read logic
since it overwrites the upper 32-bit when reading the lower 32-bit.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Jörg Rödel <joro@8bytes.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: iommu@lists.linux-foundation.org
Link: http://lkml.kernel.org/r/1487926102-13073-5-git-send-email-Suravee.Suthikulpanit@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

drivers/iommu/amd_iommu_init.c

@@ -2763,22 +2763,25 @@ static int iommu_pc_get_set_reg_val(struct amd_iommu *iommu,
 	if (WARN_ON((fxn > 0x28) || (fxn & 7)))
 		return -ENODEV;
 
-	offset = (u32)(((0x40|bank) << 12) | (cntr << 8) | fxn);
+	offset = (u32)(((0x40 | bank) << 12) | (cntr << 8) | fxn);
 
 	/* Limit the offset to the hw defined mmio region aperture */
-	max_offset_lim = (u32)(((0x40|iommu->max_banks) << 12) |
+	max_offset_lim = (u32)(((0x40 | iommu->max_banks) << 12) |
 				(iommu->max_counters << 8) | 0x28);
 	if ((offset < MMIO_CNTR_REG_OFFSET) ||
 	    (offset > max_offset_lim))
 		return -EINVAL;
 
 	if (is_write) {
-		writel((u32)*value, iommu->mmio_base + offset);
-		writel((*value >> 32), iommu->mmio_base + offset + 4);
+		u64 val = *value & GENMASK_ULL(47, 0);
+
+		writel((u32)val, iommu->mmio_base + offset);
+		writel((val >> 32), iommu->mmio_base + offset + 4);
 	} else {
 		*value = readl(iommu->mmio_base + offset + 4);
 		*value <<= 32;
-		*value = readl(iommu->mmio_base + offset);
+		*value |= readl(iommu->mmio_base + offset);
+		*value &= GENMASK_ULL(47, 0);
 	}
 
 	return 0;