[alsa-devel] [PATCH V3 3/5] ALSA: add Intel HDMI LPE audio driver for BYT/CHT-T
Anand, Jerome
jerome.anand at intel.com
Thu Jan 19 11:39:29 CET 2017
> -----Original Message-----
> From: Takashi Iwai [mailto:tiwai at suse.de]
> Sent: Wednesday, January 18, 2017 5:16 PM
> To: Anand, Jerome <jerome.anand at intel.com>
> Cc: intel-gfx at lists.freedesktop.org; alsa-devel at alsa-project.org;
> ville.syrjala at linux.intel.com; broonie at kernel.org; pierre-
> louis.bossart at linux.intel.com; Ughreja, Rakesh A
> <rakesh.a.ughreja at intel.com>
> Subject: Re: [PATCH V3 3/5] ALSA: add Intel HDMI LPE audio driver for
> BYT/CHT-T
>
> On Tue, 10 Jan 2017 06:08:39 +0100,
> Jerome Anand wrote:
> >
> > On Baytrail and Cherrytrail, HDaudio may be fused out or disabled by
> > the BIOS. This driver enables an alternate path to the i915 display
> > registers and DMA.
> >
> > Although there is no hardware path between i915 display and LPE/SST
> > audio clusters, this HDMI capability is referred to in the
> > documentation as "HDMI LPE Audio" so we keep the name for consistency.
> > There is no hardware path or control dependencies with the LPE/SST DSP
> functionality.
> >
> > The hdmi-lpe-audio driver will be probed when the i915 driver creates
> > a child platform device.
> >
> > Since this driver is neither SoC nor PCI, a new x86 folder is added
> > Additional indirections in the code will be cleaned up in the next
> > series to aid smoother DP integration
> >
> > Signed-off-by: Pierre-Louis Bossart
> > <pierre-louis.bossart at linux.intel.com>
> > Signed-off-by: Jerome Anand <jerome.anand at intel.com>
>
> Just a few knitpicks below:
>
Thank you for the detailed review.
> > --- a/sound/Makefile
> > +++ b/sound/Makefile
> > @@ -5,7 +5,7 @@ obj-$(CONFIG_SOUND) += soundcore.o
> > obj-$(CONFIG_SOUND_PRIME) += oss/
> > obj-$(CONFIG_DMASOUND) += oss/
> > obj-$(CONFIG_SND) += core/ i2c/ drivers/ isa/ pci/ ppc/ arm/ sh/ synth/
> usb/ \
> > - firewire/ sparc/ spi/ parisc/ pcmcia/ mips/ soc/ atmel/ hda/
> > + firewire/ sparc/ spi/ parisc/ pcmcia/ mips/ soc/ atmel/ hda/ x86/
> > obj-$(CONFIG_SND_AOA) += aoa/
> >
> > # This one must be compilable even if sound is configured out diff
> > --git a/sound/x86/Kconfig b/sound/x86/Kconfig new file mode 100644
> > index 0000000..e9297d0
> > --- /dev/null
> > +++ b/sound/x86/Kconfig
> > @@ -0,0 +1,16 @@
> > +menuconfig SND_X86
> > + tristate "X86 sound devices"
>
> This should depends on X86.
>
Ok will add it
>
> > + ---help---
> > +
> > + X86 sound devices that don't fall under SoC or PCI categories
> > +
> > +if SND_X86
> > +
> > +config HDMI_LPE_AUDIO
> > + tristate "HDMI audio without HDaudio on Intel Atom platforms"
> > + depends on DRM_I915
> > + default n
>
> default=n is superfluous.
>
Ok will remove it
> > + help
> > + Choose this option to support HDMI LPE Audio mode
> > +
> > +endif # SND_X86
> > diff --git a/sound/x86/Makefile b/sound/x86/Makefile new file mode
> > 100644 index 0000000..54d002d
> > --- /dev/null
> > +++ b/sound/x86/Makefile
> > @@ -0,0 +1,6 @@
> > +ccflags-y += -Iinclude/drm
>
> Do we really need this?
>
Not needed now I believe , will remove it
> > +snd-hdmi-lpe-audio-objs += \
> > + intel_hdmi_lpe_audio.o
> > +
> > +obj-$(CONFIG_HDMI_LPE_AUDIO) += snd-hdmi-lpe-audio.o
> > diff --git a/sound/x86/intel_hdmi_lpe_audio.c
> > b/sound/x86/intel_hdmi_lpe_audio.c
> > new file mode 100644
> > index 0000000..c2ebce1
> > --- /dev/null
> > +++ b/sound/x86/intel_hdmi_lpe_audio.c
> > @@ -0,0 +1,614 @@
> > +/*
> > + * intel_hdmi_lpe_audio.c - Intel HDMI LPE audio driver for Atom
> > +platforms
> > + *
> > + * Copyright (C) 2016 Intel Corp
> > + * Authors:
> > + * Jerome Anand <jerome.anand at intel.com>
> > + * Aravind Siddappaji <aravindx.siddappaji at intel.com>
> > + *
> >
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~
> > +~~~~~
> > + *
> > + * This program is free software; you can redistribute it and/or
> > +modify
> > + * it under the terms of the GNU General Public License as published
> > +by
> > + * the Free Software Foundation; version 2 of the License.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > +but
> > + * WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> GNU
> > + * General Public License for more details.
> > + *
> > + *
> >
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~
> > +~~~~~
> > + */
> > +
> > +#include <linux/platform_device.h>
> > +#include <linux/irqreturn.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/slab.h>
> > +#include <linux/module.h>
> > +#include <linux/pci.h>
> > +#include <sound/pcm.h>
> > +#include <sound/core.h>
>
> Usually sound/core.h comes before other sound/* inclusions.
>
OK, will move it up
> > +#include <sound/pcm_params.h>
> > +#include <sound/initval.h>
> > +#include <sound/control.h>
> > +#include <sound/initval.h>
> > +#include <drm/intel_lpe_audio.h>
> > +#include "intel_hdmi_lpe_audio.h"
> > +
> > +/* globals*/
> > +struct platform_device *hlpe_pdev;
> > +int hlpe_state;
> > +union otm_hdmi_eld_t hlpe_eld;
>
> Are these really globals? I couldn't find the reference from others in the
> patchset.
>
These are internal to the file. I'll make them static.
> > +
> > +struct hdmi_lpe_audio_ctx {
> > + int irq;
> > + void __iomem *mmio_start;
> > + had_event_call_back had_event_callbacks;
> > + struct snd_intel_had_interface *had_interface;
> > + void *had_pvt_data;
> > + int tmds_clock_speed;
> > + unsigned int had_config_offset;
> > + int hdmi_audio_interrupt_mask;
> > + struct work_struct hdmi_audio_wq;
> > +};
> > +
> > +static inline void hdmi_set_eld(void *eld)
>
> You need no inline unless it's really mandatory.
> Let compiler optimize. It's often smarter than us.
>
Ok, will remove inline from the code
> > +{
> > + int size;
> > +
> > + BUILD_BUG_ON(sizeof(hlpe_eld) > HDMI_MAX_ELD_BYTES);
> > +
> > + size = sizeof(hlpe_eld);
> > + memcpy((void *)&hlpe_eld, eld, size); }
> > +
> > +static inline int hdmi_get_eld(void *eld) {
> > + uint8_t *eld_data = (uint8_t *)&hlpe_eld;
> > +
> > + memcpy(eld, (void *)&hlpe_eld, sizeof(hlpe_eld));
> > +
> > + print_hex_dump_bytes("eld: ", DUMP_PREFIX_NONE, eld_data,
> > + sizeof(hlpe_eld));
> > + return 0;
> > +}
> > +
> > +
> > +static inline struct hdmi_lpe_audio_ctx *get_hdmi_context(void) {
> > + struct hdmi_lpe_audio_ctx *ctx;
> > +
> > + ctx = platform_get_drvdata(hlpe_pdev);
> > + return ctx;
> > +}
> > +
> > +/*
> > + * return whether HDMI audio device is busy.
> > + */
> > +bool mid_hdmi_audio_is_busy(void *ddev) {
> > + struct hdmi_lpe_audio_ctx *ctx;
> > + int hdmi_audio_busy = 0;
> > + struct hdmi_audio_event hdmi_audio_event;
> > +
> > + dev_dbg(&hlpe_pdev->dev, "%s: Enter", __func__);
> > +
> > + ctx = platform_get_drvdata(hlpe_pdev);
> > +
> > + if (hlpe_state == hdmi_connector_status_disconnected) {
> > + /* HDMI is not connected, assuming audio device is idle. */
> > + return false;
> > + }
> > +
> > + if (ctx->had_interface) {
> > + hdmi_audio_event.type =
> HAD_EVENT_QUERY_IS_AUDIO_BUSY;
> > + hdmi_audio_busy = ctx->had_interface->query(
> > + ctx->had_pvt_data,
> > + hdmi_audio_event);
> > + return hdmi_audio_busy != 0;
> > + }
> > + return false;
> > +}
> > +
> > +/*
> > + * return whether HDMI audio device is suspended.
>
> It's a bit confusing description. The function does suspend and returns true if
> it has suspended, or disconnected / IF doesn't exist.
>
> IMO, a standard negative error code or zero return value would be more
> straightforward in such a case.
>
Ok, I'll change the description to accommodate disconnected state too
> > + */
> > +bool mid_hdmi_audio_suspend(void *ddev) {
> > + struct hdmi_lpe_audio_ctx *ctx;
> > + struct hdmi_audio_event hdmi_audio_event;
> > + int ret = 0;
> > +
> > + ctx = platform_get_drvdata(hlpe_pdev);
> > +
> > + if (hlpe_state == hdmi_connector_status_disconnected) {
> > + /* HDMI is not connected, assuming audio device
> > + * is suspended already.
> > + */
> > + return true;
> > + }
> > +
> > + dev_dbg(&hlpe_pdev->dev, "%s: hlpe_state %d", __func__,
> > + hlpe_state);
> > +
> > + if (ctx->had_interface) {
> > + hdmi_audio_event.type = 0;
> > + ret = ctx->had_interface->suspend(ctx->had_pvt_data,
> > + hdmi_audio_event);
> > + return (ret == 0) ? true : false;
> > + }
> > + return true;
> > +}
> > +
> > +void mid_hdmi_audio_resume(void *ddev) {
> > + struct hdmi_lpe_audio_ctx *ctx;
> > +
> > + ctx = platform_get_drvdata(hlpe_pdev);
> > +
> > + if (hlpe_state == hdmi_connector_status_disconnected) {
> > + /* HDMI is not connected, there is no need
> > + * to resume audio device.
> > + */
> > + return;
> > + }
> > +
> > + dev_dbg(&hlpe_pdev->dev, "%s: hlpe_state %d", __func__,
> > +hlpe_state);
> > +
> > + if (ctx->had_interface)
> > + ctx->had_interface->resume(ctx->had_pvt_data);
> > +}
> > +
> > +void mid_hdmi_audio_signal_event(enum had_event_type event) {
> > + struct hdmi_lpe_audio_ctx *ctx;
> > +
> > + dev_dbg(&hlpe_pdev->dev, "%s: Enter\n", __func__);
> > +
> > + ctx = platform_get_drvdata(hlpe_pdev);
> > +
> > + if (ctx->had_event_callbacks)
> > + (*ctx->had_event_callbacks)(event,
> > + ctx->had_pvt_data);
>
> Isn't this racy? This dispatcher seems called from multiple places including
> the interrupt handler below.
>
No, It's taken care of in the respective callbacks based on the event
>
> > +}
> > +
> > +/**
> > + * hdmi_audio_write:
> > + * used to write into display controller HDMI audio registers.
>
> No need to use kernel-doc style comments here unless you really want to list
> in the kernel API documentation.
>
Ok, will remove the comments
>
> > + *
> > + */
> > +static int hdmi_audio_write(uint32_t reg, uint32_t val)
>
> We don't use uint32_t in kernel codes, but a simpler form, u32, is preferred
> in most cases. uint32_t is still allowed, but it's usually only for user API
> definitions.
>
Ok, will change to u32, u16 and u8 respectively
>
> > +{
> > + struct hdmi_lpe_audio_ctx *ctx;
> > +
> > + ctx = platform_get_drvdata(hlpe_pdev);
> > +
> > + dev_dbg(&hlpe_pdev->dev, "%s: reg[0x%x] = 0x%x\n", __func__,
> reg,
> > +val);
> > +
> > + iowrite32(val, (ctx->mmio_start+reg));
> > +
> > + return 0;
> > +}
> > +
> > +/**
> > + * hdmi_audio_read:
> > + * used to get the register value read from
> > + * display controller HDMI audio registers.
> > + */
> > +static int hdmi_audio_read(uint32_t reg, uint32_t *val) {
> > + struct hdmi_lpe_audio_ctx *ctx;
> > +
> > + ctx = platform_get_drvdata(hlpe_pdev);
> > + *val = ioread32(ctx->mmio_start+reg);
> > + dev_dbg(&hlpe_pdev->dev, "%s: reg[0x%x] = 0x%x\n", __func__,
> reg, *val);
> > + return 0;
> > +}
> > +
> > +/**
> > + * hdmi_audio_rmw:
> > + * used to update the masked bits in display controller HDMI
> > + * audio registers.
> > + */
> > +static int hdmi_audio_rmw(uint32_t reg, uint32_t val, uint32_t mask)
> > +{
> > + struct hdmi_lpe_audio_ctx *ctx;
> > + uint32_t val_tmp = 0;
> > +
> > + ctx = platform_get_drvdata(hlpe_pdev);
> > +
> > + val_tmp = (val & mask) |
> > + ((ioread32(ctx->mmio_start + reg)) & ~mask);
> > +
> > + iowrite32(val_tmp, (ctx->mmio_start+reg));
> > + dev_dbg(&hlpe_pdev->dev, "%s: reg[0x%x] = 0x%x\n", __func__,
> reg,
> > +val_tmp);
> > +
> > + return 0;
> > +}
> > +
> > +/**
> > + * hdmi_audio_get_caps:
> > + * used to return the HDMI audio capabilities.
> > + * e.g. resolution, frame rate.
> > + */
> > +static int hdmi_audio_get_caps(enum had_caps_list get_element,
> > + void *capabilities)
> > +{
> > + struct hdmi_lpe_audio_ctx *ctx;
> > + int ret = 0;
> > +
> > + ctx = get_hdmi_context();
> > +
> > + dev_dbg(&hlpe_pdev->dev, "%s: Enter\n", __func__);
> > +
> > + switch (get_element) {
> > + case HAD_GET_ELD:
> > + ret = hdmi_get_eld(capabilities);
> > + break;
> > + case HAD_GET_DISPLAY_RATE:
> > + /* ToDo: Verify if sampling freq logic is correct */
> > + memcpy(capabilities, &(ctx->tmds_clock_speed),
> > + sizeof(uint32_t));
>
> Why memcpy? Both source and destination are 32bit int, no?
>
Do you think *(int *)capabilities = ctx->tmds_clock_speed is better than memcpy?
> > + dev_dbg(&hlpe_pdev->dev, "%s: tmds_clock_speed =
> 0x%x\n", __func__,
> > + ctx->tmds_clock_speed);
> > + break;
> > + default:
> > + break;
> > + }
> > +
> > + return ret;
> > +}
> > +
> > +/**
> > + * hdmi_audio_get_register_base
> > + * used to get the current hdmi base address */ int
> > +hdmi_audio_get_register_base(uint32_t **reg_base,
> > + uint32_t *config_offset)
> > +{
> > + struct hdmi_lpe_audio_ctx *ctx;
> > +
> > + ctx = platform_get_drvdata(hlpe_pdev);
> > + *reg_base = (uint32_t *)(ctx->mmio_start);
> > + *config_offset = ctx->had_config_offset;
> > + dev_dbg(&hlpe_pdev->dev, "%s: reg_base = 0x%p, cfg_off =
> 0x%x\n", __func__,
> > + *reg_base, *config_offset);
> > + return 0;
>
> Well, I see no reason why this function / callback is needed.
> The base address is never referred in other codes, and the config_offset is
> always passed to read/write accessors, so it can be calculated there directly.
>
> Any other missing cases?
>
I wanted to have a cleaner separation, hence added this function in this file rather
Than deriving it. So would prefer to keep it.
>
> > +}
> > +
> > +/**
> > + * hdmi_audio_set_caps:
> > + * used to set the HDMI audio capabilities.
> > + * e.g. Audio INT.
> > + */
> > +int hdmi_audio_set_caps(enum had_caps_list set_element,
> > + void *capabilties)
> > +{
> > + struct hdmi_lpe_audio_ctx *ctx;
> > +
> > + ctx = platform_get_drvdata(hlpe_pdev);
> > +
> > + dev_dbg(&hlpe_pdev->dev, "%s: cap_id = 0x%x\n", __func__,
> > +set_element);
> > +
> > + switch (set_element) {
> > + case HAD_SET_ENABLE_AUDIO_INT:
> > + {
> > + uint32_t status_reg;
> > +
> > + hdmi_audio_read(AUD_HDMI_STATUS_v2 +
> > + ctx->had_config_offset, &status_reg);
> > + status_reg |=
> > + HDMI_AUDIO_BUFFER_DONE |
> HDMI_AUDIO_UNDERRUN;
> > + hdmi_audio_write(AUD_HDMI_STATUS_v2 +
> > + ctx->had_config_offset, status_reg);
> > + hdmi_audio_read(AUD_HDMI_STATUS_v2 +
> > + ctx->had_config_offset, &status_reg);
> > +
> > + }
> > + break;
> > + default:
> > + break;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static struct hdmi_audio_registers_ops hdmi_audio_reg_ops = {
> > + .hdmi_audio_get_register_base = hdmi_audio_get_register_base,
> > + .hdmi_audio_read_register = hdmi_audio_read,
> > + .hdmi_audio_write_register = hdmi_audio_write,
> > + .hdmi_audio_read_modify = hdmi_audio_rmw, };
> > +
> > +static struct hdmi_audio_query_set_ops hdmi_audio_get_set_ops = {
> > + .hdmi_audio_get_caps = hdmi_audio_get_caps,
> > + .hdmi_audio_set_caps = hdmi_audio_set_caps, };
> > +
> > +int mid_hdmi_audio_setup(
> > + had_event_call_back audio_callbacks,
> > + struct hdmi_audio_registers_ops *reg_ops,
> > + struct hdmi_audio_query_set_ops *query_ops) {
> > + struct hdmi_lpe_audio_ctx *ctx;
> > +
> > + ctx = platform_get_drvdata(hlpe_pdev);
> > +
> > + dev_dbg(&hlpe_pdev->dev, "%s: called\n", __func__);
> > +
> > + reg_ops->hdmi_audio_get_register_base =
> > + (hdmi_audio_reg_ops.hdmi_audio_get_register_base);
> > + reg_ops->hdmi_audio_read_register =
> > + (hdmi_audio_reg_ops.hdmi_audio_read_register);
> > + reg_ops->hdmi_audio_write_register =
> > + (hdmi_audio_reg_ops.hdmi_audio_write_register);
> > + reg_ops->hdmi_audio_read_modify =
> > + (hdmi_audio_reg_ops.hdmi_audio_read_modify);
> > + query_ops->hdmi_audio_get_caps =
> > + hdmi_audio_get_set_ops.hdmi_audio_get_caps;
> > + query_ops->hdmi_audio_set_caps =
> > + hdmi_audio_get_set_ops.hdmi_audio_set_caps;
> > +
> > + ctx->had_event_callbacks = audio_callbacks;
> > +
> > + return 0;
> > +}
> > +
> > +void _had_wq(struct work_struct *work)
>
> Missing static.
>
Ok, will add
>
> thanks,
>
> Takashi
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