drm/omap: add dmm_read() and dmm_write() wrappers

This patch adds wrapper functions for readl() and writel(), dmm_read()
and dmm_write(), so that we can implement workaround for DRA7 errata
i878.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

drivers/gpu/drm/omapdrm/omap_dmm_tiler.c

@@ -79,6 +79,16 @@ static const uint32_t reg[][4] = {
 			DMM_PAT_DESCR__2, DMM_PAT_DESCR__3},
 };
 
+static u32 dmm_read(struct dmm *dmm, u32 reg)
+{
+	return readl(dmm->base + reg);
+}
+
+static void dmm_write(struct dmm *dmm, u32 val, u32 reg)
+{
+	writel(val, dmm->base + reg);
+}
+
 /* simple allocator to grab next 16 byte aligned memory from txn */
 static void *alloc_dma(struct dmm_txn *txn, size_t sz, dma_addr_t *pa)
 {
@@ -108,7 +118,7 @@ static int wait_status(struct refill_engine *engine, uint32_t wait_mask)
 
 	i = DMM_FIXED_RETRY_COUNT;
 	while (true) {
-		r = readl(dmm->base + reg[PAT_STATUS][engine->id]);
+		r = dmm_read(dmm, reg[PAT_STATUS][engine->id]);
 		err = r & DMM_PATSTATUS_ERR;
 		if (err)
 			return -EFAULT;
@@ -140,11 +150,11 @@ static void release_engine(struct refill_engine *engine)
 static irqreturn_t omap_dmm_irq_handler(int irq, void *arg)
 {
 	struct dmm *dmm = arg;
-	uint32_t status = readl(dmm->base + DMM_PAT_IRQSTATUS);
+	uint32_t status = dmm_read(dmm, DMM_PAT_IRQSTATUS);
 	int i;
 
 	/* ack IRQ */
-	writel(status, dmm->base + DMM_PAT_IRQSTATUS);
+	dmm_write(dmm, status, DMM_PAT_IRQSTATUS);
 
 	for (i = 0; i < dmm->num_engines; i++) {
 		if (status & DMM_IRQSTAT_LST) {
@@ -264,7 +274,7 @@ static int dmm_txn_commit(struct dmm_txn *txn, bool wait)
 	txn->last_pat->next_pa = 0;
 
 	/* write to PAT_DESCR to clear out any pending transaction */
-	writel(0x0, dmm->base + reg[PAT_DESCR][engine->id]);
+	dmm_write(dmm, 0x0, reg[PAT_DESCR][engine->id]);
 
 	/* wait for engine ready: */
 	ret = wait_status(engine, DMM_PATSTATUS_READY);
@@ -280,8 +290,7 @@ static int dmm_txn_commit(struct dmm_txn *txn, bool wait)
 	smp_mb();
 
 	/* kick reload */
-	writel(engine->refill_pa,
-		dmm->base + reg[PAT_DESCR][engine->id]);
+	dmm_write(dmm, engine->refill_pa, reg[PAT_DESCR][engine->id]);
 
 	if (wait) {
 		if (!wait_for_completion_timeout(&engine->compl,
@@ -657,7 +666,7 @@ static int omap_dmm_probe(struct platform_device *dev)
 
 	omap_dmm->dev = &dev->dev;
 
-	hwinfo = readl(omap_dmm->base + DMM_PAT_HWINFO);
+	hwinfo = dmm_read(omap_dmm, DMM_PAT_HWINFO);
 	omap_dmm->num_engines = (hwinfo >> 24) & 0x1F;
 	omap_dmm->num_lut = (hwinfo >> 16) & 0x1F;
 	omap_dmm->container_width = 256;
@@ -666,7 +675,7 @@ static int omap_dmm_probe(struct platform_device *dev)
 	atomic_set(&omap_dmm->engine_counter, omap_dmm->num_engines);
 
 	/* read out actual LUT width and height */
-	pat_geom = readl(omap_dmm->base + DMM_PAT_GEOMETRY);
+	pat_geom = dmm_read(omap_dmm, DMM_PAT_GEOMETRY);
 	omap_dmm->lut_width = ((pat_geom >> 16) & 0xF) << 5;
 	omap_dmm->lut_height = ((pat_geom >> 24) & 0xF) << 5;
 
@@ -676,12 +685,12 @@ static int omap_dmm_probe(struct platform_device *dev)
 		omap_dmm->num_lut++;
 
 	/* initialize DMM registers */
-	writel(0x88888888, omap_dmm->base + DMM_PAT_VIEW__0);
-	writel(0x88888888, omap_dmm->base + DMM_PAT_VIEW__1);
-	writel(0x80808080, omap_dmm->base + DMM_PAT_VIEW_MAP__0);
-	writel(0x80000000, omap_dmm->base + DMM_PAT_VIEW_MAP_BASE);
-	writel(0x88888888, omap_dmm->base + DMM_TILER_OR__0);
-	writel(0x88888888, omap_dmm->base + DMM_TILER_OR__1);
+	dmm_write(omap_dmm, 0x88888888, DMM_PAT_VIEW__0);
+	dmm_write(omap_dmm, 0x88888888, DMM_PAT_VIEW__1);
+	dmm_write(omap_dmm, 0x80808080, DMM_PAT_VIEW_MAP__0);
+	dmm_write(omap_dmm, 0x80000000, DMM_PAT_VIEW_MAP_BASE);
+	dmm_write(omap_dmm, 0x88888888, DMM_TILER_OR__0);
+	dmm_write(omap_dmm, 0x88888888, DMM_TILER_OR__1);
 
 	ret = request_irq(omap_dmm->irq, omap_dmm_irq_handler, IRQF_SHARED,
 				"omap_dmm_irq_handler", omap_dmm);
@@ -699,7 +708,7 @@ static int omap_dmm_probe(struct platform_device *dev)
 	 * buffers for accelerated pan/scroll) and FILL_DSC<n> which
 	 * we just generally don't care about.
 	 */
-	writel(0x7e7e7e7e, omap_dmm->base + DMM_PAT_IRQENABLE_SET);
+	dmm_write(omap_dmm, 0x7e7e7e7e, DMM_PAT_IRQENABLE_SET);
 
 	omap_dmm->dummy_page = alloc_page(GFP_KERNEL | __GFP_DMA32);
 	if (!omap_dmm->dummy_page) {