Thread (88 messages) 88 messages, 11 authors, 2008-01-10

Re: [PATCH] ASoC drivers for the Freescale MPC8610 SoC

From: Olof Johansson <hidden>
Date: 2007-12-20 04:00:15
Also in: alsa-devel

Hi,

This is a fairly substantial driver to get through, but here are some
initial comments on some of the simpler stuff:


On Wed, Dec 19, 2007 at 06:03:09PM -0600, Timur Tabi wrote:
This patch adds ALSA SoC device drivers for the Freescale MPC8610 SoC
and the MPC8610-HPCD reference board.
[...]
quoted hunk ↗ jump to hunk
diff --git a/arch/powerpc/platforms/86xx/mpc8610_hpcd.c b/arch/powerpc/platforms/86xx/mpc8610_hpcd.c
index 6390895..6e1bde3 100644
--- a/arch/powerpc/platforms/86xx/mpc8610_hpcd.c
+++ b/arch/powerpc/platforms/86xx/mpc8610_hpcd.c
@@ -34,9 +34,27 @@
 
 #include <asm/mpic.h>
 
+#include <asm/of_platform.h>
 #include <sysdev/fsl_pci.h>
 #include <sysdev/fsl_soc.h>
 
+static struct of_device_id mpc8610_ids[] = {
+	{ .type = "soc", },
+	{}
Please scan based on compatible instead of device_type.
quoted hunk ↗ jump to hunk
diff --git a/sound/soc/fsl/Kconfig b/sound/soc/fsl/Kconfig
new file mode 100644
index 0000000..4a5bbd2
--- /dev/null
+++ b/sound/soc/fsl/Kconfig
@@ -0,0 +1,21 @@
+menu "ALSA SoC audio for Freescale SOCs"
+
+config SND_SOC_MPC8610
+	bool "ALSA SoC support for the MPC8610 SOC"
+	depends on SND_SOC #&& MPC8610_HPCD
+	default y #if MPC8610
+	help
+	  Say Y if you want to add support for codecs attached to the SSI
+          device on an MPC8610.
Don't default configs to 'y'. Also, what's with the commented-out
dependencies and if?
+config SND_SOC_MPC8610_HPCD
+	# ALSA SoC support for Freescale MPC8610HPCD
+	bool "ALSA SoC support for the Freescale MPC8610 HPCD board"
+	depends on SND_SOC_MPC8610
+	select SND_SOC_CS4270
+	select SND_SOC_CS4270_VD33_ERRATA
+	default y #if MPC8610_HPCD
+	help
+	  Say Y if you want to enable audio on the Freescale MPC8610 HPCD.
Same here w.r.t. defaults and dependencies.
quoted hunk ↗ jump to hunk
diff --git a/sound/soc/fsl/fsl_dma.c b/sound/soc/fsl/fsl_dma.c
new file mode 100644
index 0000000..6b86be0
--- /dev/null
+++ b/sound/soc/fsl/fsl_dma.c
@@ -0,0 +1,819 @@
+/*
+ * Freescale DMA ALSA SoC PCM driver
+ *
+ * Author: Timur Tabi <timur@freescale.com>
+ *
+ * Copyright 2007 Freescale Semiconductor, Inc.  This file is licensed under
+ * the terms of the GNU General Public License version 2.  This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ *
+ * This driver implements ASoC support for the Elo DMA controller, which is
+ * the DMA controller on Freescale 83xx, 85xx, and 86xx SOCs. In ALSA terms,
+ * the PCM driver is what handles the DMA buffer.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+
+#include <sound/driver.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+
+#include <asm/io.h>
+
+#include "fsl_dma.h"
+
+/*
+ * The formats that the DMA controller supports, which is anything
+ * that is 8, 16, or 32 bits.
+ */
+#define FSLDMA_PCM_FORMATS (SNDRV_PCM_FMTBIT_S8 	| \
+			    SNDRV_PCM_FMTBIT_U8 	| \
+			    SNDRV_PCM_FMTBIT_S16_LE     | \
+			    SNDRV_PCM_FMTBIT_S16_BE     | \
+			    SNDRV_PCM_FMTBIT_U16_LE     | \
+			    SNDRV_PCM_FMTBIT_U16_BE     | \
+			    SNDRV_PCM_FMTBIT_S24_LE     | \
+			    SNDRV_PCM_FMTBIT_S24_BE     | \
+			    SNDRV_PCM_FMTBIT_U24_LE     | \
+			    SNDRV_PCM_FMTBIT_U24_BE     | \
+			    SNDRV_PCM_FMTBIT_S32_LE     | \
+			    SNDRV_PCM_FMTBIT_S32_BE     | \
+			    SNDRV_PCM_FMTBIT_U32_LE     | \
+			    SNDRV_PCM_FMTBIT_U32_BE)
+
+#define FSLDMA_PCM_RATES (SNDRV_PCM_RATE_5512 | SNDRV_PCM_RATE_8000_192000 | \
+			  SNDRV_PCM_RATE_CONTINUOUS)
+
+/* DMA global data.  This structure is used by fsl_dma_open() to determine
+ * which DMA channels to assign to a substream.  Unfortunately, ASoC V1 does
+ * not allow the machine driver to provide this information to the PCM
+ * driver in advance, and there's no way to differentiate between the two
+ * DMA controllers.  So for now, this driver only supports one SSI device
+ * using two DMA channels.  We cannot support multiple DMA devices.
+ *
+ * ssi_stx_phys: bus address of SSI STX register
+ * ssi_srx_phys: bus address of SSI SRX register
+ * dma_channel: pointer to the DMA channel's registers
+ * irq: IRQ for this DMA channel
+ * assigned: set to 1 if that DMA channel is assigned to a substream
+ */
This goes for the whole patch: You've got good documentation, but it's
not in docbook format. Please reformat it since it should be a pretty
simple thing to do.
+/*
+ * Initialize this PCM driver.
+ *
+ * This function is called when the codec driver calls snd_soc_new_pcms(),
+ * once for each .dai_link in the machine driver's snd_soc_machine
+ * structure.
+ */
+static int fsl_dma_new(struct snd_card *card, struct snd_soc_codec_dai *dai,
+	struct snd_pcm *pcm)
+{
+	static u64 fsl_dma_dmamask = 0xffffffff;
+	int ret;
+
+	if (!card->dev->dma_mask)
+		card->dev->dma_mask = &fsl_dma_dmamask;
I haven't read how your channel allocation works, but providing a
pointer to a local static variable is a bit fishy no matter what.
+	/* Find the DMA channels to use.  For now, we always use the first DMA
+	   controller. */
+	for_each_compatible_node(dma_np, NULL, "fsl,mpc8610-dma") {
+		iprop = of_get_property(dma_np, "cell-index", NULL);
+		if (iprop && (*iprop == 0)) {
+			of_node_put(dma_np);
+			break;
+		}
+	}
Do you ever anticipate having other dma users on the system, such as
memcpy offload? You'll probably need allocation support for channels
when that day comes (I ended up writing a simple library for dma channel
management for that very reason on my platform).


-Olof
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