Thread (42 messages) 42 messages, 4 authors, 2015-10-13

Re: [PATCH v2 4/9] dmaengine: st_fdma: Add STMicroelectronics FDMA engine driver support

From: Arnd Bergmann <arnd@arndb.de>
Date: 2015-09-11 20:30:30
Also in: linux-arm-kernel, lkml

On Friday 11 September 2015 15:14:26 Peter Griffin wrote:
+
+#include "st_fdma.h"
Just move the contents of that file here, no other driver should
be including it.
+static struct dma_chan *st_fdma_of_xlate(struct of_phandle_args *dma_spec,
+					 struct of_dma *ofdma)
+{
+	struct st_fdma_dev *fdev = ofdma->of_dma_data;
+	struct st_fdma_cfg cfg;
+
+	if (dma_spec->args_count < 1)
+		return NULL;
+
+	cfg.of_node = dma_spec->np;
+	cfg.req_line = dma_spec->args[0];
+	cfg.req_ctrl = 0;
+	cfg.type = ST_FDMA_TYPE_FREE_RUN;
+
+	if (dma_spec->args_count > 1)
+		cfg.req_ctrl = dma_spec->args[1] & REQ_CTRL_CFG_MASK;
+
+	if (dma_spec->args_count > 2)
+		cfg.type = dma_spec->args[2];
The binding mandates #dma-cells=<3>, so you can just return an error
otherwise.
+	dev_dbg(fdev->dev, "xlate req_line:%d type:%d req_ctrl:%#x\n",
+		cfg.req_line, cfg.type, cfg.req_ctrl);
+
+	return dma_request_channel(fdev->dma_device.cap_mask,
+			st_fdma_filter_fn, &cfg);
+}
Why this indirection? You should be able to just use
dma_get_any_slave_channel() to get the first available channel and
then configure it the same way that the filter function does.
+bool st_fdma_filter_fn(struct dma_chan *chan, void *param)
+{
+	struct st_fdma_cfg *config = param;
+	struct st_fdma_chan *fchan = to_st_fdma_chan(chan);
+
+	if (!param)
+		return false;
+
+	if (fchan->fdev->dma_device.dev->of_node != config->of_node)
+		return false;
+
+	fchan->cfg = *config;
+
+	return true;
+}
Please drop this until there is a board file that references the
function. Otherwise it's just dead code. I assume there are some
users in arch/sh/ in a private tree?

	Arnd
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