dma: tegra: register as an OF DMA controller

Call of_dma_controller_register() so that DMA clients can look up the
Tegra DMA controller using standard APIs. This requires the of_xlate()
function to save off the DMA slave ID, and for tegra_dma_slave_config()
not to over-write this information; once DMA client drivers are converted
to dma_request_slave_channel() and DT-based lookups, they won't set this
field of struct dma_slave_config anymore.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Thierry Reding <treding@nvidia.com>

1 files changed, 36 insertions, 3 deletions

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index afa5844c9346..d11bb3620f27 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -1,7 +1,7 @@
 /*
  * DMA driver for Nvidia's Tegra20 APB DMA controller.
  *
- * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2012-2013, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -29,6 +29,7 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/of_dma.h>
 #include <linux/platform_device.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
@@ -199,6 +200,7 @@ struct tegra_dma_channel {
         void                    *callback_param;
 
         /* Channel-slave specific configuration */
+        unsigned int slave_id;
         struct dma_slave_config dma_sconfig;
         struct tegra_dma_channel_regs   channel_reg;
 };
@@ -340,6 +342,8 @@ static int tegra_dma_slave_config(struct dma_chan *dc,
         }
 
         memcpy(&tdc->dma_sconfig, sconfig, sizeof(*sconfig));
+        if (!tdc->slave_id)
+                tdc->slave_id = sconfig->slave_id;
         tdc->config_init = true;
         return 0;
 }
@@ -942,7 +946,7 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_slave_sg(
         ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32;
 
         csr |= TEGRA_APBDMA_CSR_ONCE | TEGRA_APBDMA_CSR_FLOW;
-        csr |= tdc->dma_sconfig.slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
+        csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
         if (flags & DMA_PREP_INTERRUPT)
                 csr |= TEGRA_APBDMA_CSR_IE_EOC;
 
@@ -1086,7 +1090,7 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_dma_cyclic(
         csr |= TEGRA_APBDMA_CSR_FLOW;
         if (flags & DMA_PREP_INTERRUPT)
                 csr |= TEGRA_APBDMA_CSR_IE_EOC;
-        csr |= tdc->dma_sconfig.slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
+        csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
 
         apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;
 
@@ -1206,6 +1210,25 @@ static void tegra_dma_free_chan_resources(struct dma_chan *dc)
                 kfree(sg_req);
         }
         clk_disable_unprepare(tdma->dma_clk);
+
+        tdc->slave_id = 0;
+}
+
+static struct dma_chan *tegra_dma_of_xlate(struct of_phandle_args *dma_spec,
+                                           struct of_dma *ofdma)
+{
+        struct tegra_dma *tdma = ofdma->of_dma_data;
+        struct dma_chan *chan;
+        struct tegra_dma_channel *tdc;
+
+        chan = dma_get_any_slave_channel(&tdma->dma_dev);
+        if (!chan)
+                return NULL;
+
+        tdc = to_tegra_dma_chan(chan);
+        tdc->slave_id = dma_spec->args[0];
+
+        return chan;
 }
 
 /* Tegra20 specific DMA controller information */
@@ -1383,10 +1406,20 @@ static int tegra_dma_probe(struct platform_device *pdev)
                 goto err_irq;
         }
 
+        ret = of_dma_controller_register(pdev->dev.of_node,
+                                         tegra_dma_of_xlate, tdma);
+        if (ret < 0) {
+                dev_err(&pdev->dev,
+                        "Tegra20 APB DMA OF registration failed %d\n", ret);
+                goto err_unregister_dma_dev;
+        }
+
         dev_info(&pdev->dev, "Tegra20 APB DMA driver register %d channels\n",
                         cdata->nr_channels);
         return 0;
 
+err_unregister_dma_dev:
+        dma_async_device_unregister(&tdma->dma_dev);
 err_irq:
         while (--i >= 0) {
                 struct tegra_dma_channel *tdc = &tdma->channels[i];