[PATCH v5 09/17] soundwire: intel: remove platform devices and use 'Master Devices' instead

[Pierre-Louis Bossart]

Use sdw_master_device and driver instead of platform devices

To quote GregKH:

"Don't mess with a platform device unless you really have no other
possible choice. And even then, don't do it and try to do something
else. Platform devices are really abused, don't perpetuate it "

In addition, rather than a plain-vanilla init/exit, this patch
provides 3 steps in the initialization (ACPI scan, probe, startup)
which makes it easier to verify hardware support for SoundWire,
allocate required resources as early as possible, and conversely help
make the startup() callback lighter-weight with only hardware register
setup.

Signed-off-by: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
---
 drivers/soundwire/intel.c      |  91 ++++++-----
 drivers/soundwire/intel.h      |   8 +-
 drivers/soundwire/intel_init.c | 275 ++++++++++++++++++++++++---------
 3 files changed, 267 insertions(+), 107 deletions(-)

diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index 64f97bb1a135..36dbcbab0d65 100644
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -92,8 +92,6 @@
 #define SDW_ALH_STRMZCFG_DMAT		GENMASK(7, 0)
 #define SDW_ALH_STRMZCFG_CHN		GENMASK(19, 16)
 
-#define SDW_INTEL_QUIRK_MASK_BUS_DISABLE	BIT(1)
-
 enum intel_pdi_type {
 	INTEL_PDI_IN = 0,
 	INTEL_PDI_OUT = 1,
@@ -923,24 +921,23 @@ static int intel_init(struct sdw_intel *sdw)
 /*
  * probe and init
  */
-static int intel_probe(struct platform_device *pdev)
+static int intel_master_probe(struct sdw_master_device *md, void *link_ctx)
 {
-	struct sdw_cdns_stream_config config;
 	struct sdw_intel *sdw;
 	int ret;
 
-	sdw = devm_kzalloc(&pdev->dev, sizeof(*sdw), GFP_KERNEL);
+	sdw = devm_kzalloc(&md->dev, sizeof(*sdw), GFP_KERNEL);
 	if (!sdw)
 		return -ENOMEM;
 
-	sdw->instance = pdev->id;
-	sdw->link_res = dev_get_platdata(&pdev->dev);
-	sdw->cdns.dev = &pdev->dev;
+	sdw->instance = md->link_id;
+	sdw->link_res = link_ctx;
+	sdw->cdns.dev = &md->dev;
 	sdw->cdns.registers = sdw->link_res->registers;
-	sdw->cdns.instance = sdw->instance;
+	sdw->cdns.instance = md->link_id;
 	sdw->cdns.msg_count = 0;
-	sdw->cdns.bus.dev = &pdev->dev;
-	sdw->cdns.bus.link_id = pdev->id;
+	sdw->cdns.bus.dev = &md->dev;
+	sdw->cdns.bus.link_id = md->link_id;
 
 	sdw_cdns_probe(&sdw->cdns);
 
@@ -948,16 +945,50 @@ static int intel_probe(struct platform_device *pdev)
 	sdw_intel_ops.read_prop = intel_prop_read;
 	sdw->cdns.bus.ops = &sdw_intel_ops;
 
-	platform_set_drvdata(pdev, sdw);
+	md->pdata = sdw;
+
+	/* set driver data, accessed by snd_soc_dai_set_drvdata() */
+	dev_set_drvdata(&md->dev, &sdw->cdns);
 
 	ret = sdw_add_bus_master(&sdw->cdns.bus);
 	if (ret) {
-		dev_err(&pdev->dev, "sdw_add_bus_master fail: %d\n", ret);
+		dev_err(&md->dev, "sdw_add_bus_master fail: %d\n", ret);
 		return ret;
 	}
 
 	if (sdw->cdns.bus.prop.hw_disabled) {
-		dev_info(&pdev->dev, "SoundWire master %d is disabled, ignoring\n",
+		dev_info(&md->dev, "SoundWire master %d is disabled, ignoring\n",
+			 sdw->cdns.bus.link_id);
+		return 0;
+	}
+
+	/* Acquire IRQ */
+	ret = request_threaded_irq(sdw->link_res->irq,
+				   sdw_cdns_irq, sdw_cdns_thread,
+				   IRQF_SHARED, KBUILD_MODNAME, &sdw->cdns);
+	if (ret < 0) {
+		dev_err(sdw->cdns.dev, "unable to grab IRQ %d, disabling device\n",
+			sdw->link_res->irq);
+		goto err_init;
+	}
+
+	return 0;
+
+err_init:
+	sdw_delete_bus_master(&sdw->cdns.bus);
+	return ret;
+}
+
+static int intel_master_startup(struct sdw_master_device *md)
+{
+	struct sdw_cdns_stream_config config;
+	struct sdw_intel *sdw;
+	int ret;
+
+	sdw = md->pdata;
+
+	if (sdw->cdns.bus.prop.hw_disabled) {
+		dev_info(&md->dev, "SoundWire master %d is disabled, ignoring\n",
 			 sdw->cdns.bus.link_id);
 		return 0;
 	}
@@ -975,16 +1006,6 @@ static int intel_probe(struct platform_device *pdev)
 
 	intel_pdi_ch_update(sdw);
 
-	/* Acquire IRQ */
-	ret = request_threaded_irq(sdw->link_res->irq,
-				   sdw_cdns_irq, sdw_cdns_thread,
-				   IRQF_SHARED, KBUILD_MODNAME, &sdw->cdns);
-	if (ret < 0) {
-		dev_err(sdw->cdns.dev, "unable to grab IRQ %d, disabling device\n",
-			sdw->link_res->irq);
-		goto err_init;
-	}
-
 	ret = sdw_cdns_enable_interrupt(&sdw->cdns, true);
 	if (ret < 0) {
 		dev_err(sdw->cdns.dev, "cannot enable interrupts\n");
@@ -1011,17 +1032,17 @@ static int intel_probe(struct platform_device *pdev)
 
 err_interrupt:
 	sdw_cdns_enable_interrupt(&sdw->cdns, false);
-	free_irq(sdw->link_res->irq, sdw);
 err_init:
+	free_irq(sdw->link_res->irq, sdw);
 	sdw_delete_bus_master(&sdw->cdns.bus);
 	return ret;
 }
 
-static int intel_remove(struct platform_device *pdev)
+static int intel_master_remove(struct sdw_master_device *md)
 {
 	struct sdw_intel *sdw;
 
-	sdw = platform_get_drvdata(pdev);
+	sdw = md->pdata;
 
 	if (!sdw->cdns.bus.prop.hw_disabled) {
 		intel_debugfs_exit(sdw);
@@ -1031,19 +1052,17 @@ static int intel_remove(struct platform_device *pdev)
 	}
 	sdw_delete_bus_master(&sdw->cdns.bus);
 
+	device_unregister(&md->dev);
+
 	return 0;
 }
 
-static struct platform_driver sdw_intel_drv = {
-	.probe = intel_probe,
-	.remove = intel_remove,
-	.driver = {
-		.name = "int-sdw",
-
-	},
+struct sdw_md_driver intel_sdw_driver = {
+	.probe = intel_master_probe,
+	.startup = intel_master_startup,
+	.remove = intel_master_remove,
 };
-
-module_platform_driver(sdw_intel_drv);
+EXPORT_SYMBOL(intel_sdw_driver);
 
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_ALIAS("platform:int-sdw");
diff --git a/drivers/soundwire/intel.h b/drivers/soundwire/intel.h
index 38b7c125fb10..cfab2f00214d 100644
--- a/drivers/soundwire/intel.h
+++ b/drivers/soundwire/intel.h
@@ -7,7 +7,7 @@
 /**
  * struct sdw_intel_link_res - Soundwire Intel link resource structure,
  * typically populated by the controller driver.
- * @pdev: platform_device
+ * @md: master device
  * @mmio_base: mmio base of SoundWire registers
  * @registers: Link IO registers base
  * @shim: Audio shim pointer
@@ -17,7 +17,7 @@
  * @dev: device implementing hw_params and free callbacks
  */
 struct sdw_intel_link_res {
-	struct platform_device *pdev;
+	struct sdw_master_device *md;
 	void __iomem *mmio_base; /* not strictly needed, useful for debug */
 	void __iomem *registers;
 	void __iomem *shim;
@@ -27,4 +27,8 @@ struct sdw_intel_link_res {
 	struct device *dev;
 };
 
+#define SDW_INTEL_QUIRK_MASK_BUS_DISABLE      BIT(1)
+
+extern struct sdw_md_driver intel_sdw_driver;
+
 #endif /* __SDW_INTEL_LOCAL_H */
diff --git a/drivers/soundwire/intel_init.c b/drivers/soundwire/intel_init.c
index 4b769409f6f8..42f7ae034bea 100644
--- a/drivers/soundwire/intel_init.c
+++ b/drivers/soundwire/intel_init.c
@@ -11,7 +11,7 @@
 #include <linux/export.h>
 #include <linux/io.h>
 #include <linux/module.h>
-#include <linux/platform_device.h>
+#include <linux/soundwire/sdw.h>
 #include <linux/soundwire/sdw_intel.h>
 #include "intel.h"
 
@@ -23,22 +23,47 @@
 #define SDW_LINK_BASE		0x30000
 #define SDW_LINK_SIZE		0x10000
 
-static int link_mask;
-module_param_named(sdw_link_mask, link_mask, int, 0444);
+static int ctrl_link_mask;
+module_param_named(sdw_link_mask, ctrl_link_mask, int, 0444);
 MODULE_PARM_DESC(sdw_link_mask, "Intel link mask (one bit per link)");
 
-static int sdw_intel_cleanup_pdev(struct sdw_intel_ctx *ctx)
+static bool is_link_enabled(struct fwnode_handle *fw_node, int i)
+{
+	struct fwnode_handle *link;
+	char name[32];
+	u32 quirk_mask = 0;
+
+	/* Find master handle */
+	snprintf(name, sizeof(name),
+		 "mipi-sdw-link-%d-subproperties", i);
+
+	link = fwnode_get_named_child_node(fw_node, name);
+	if (!link)
+		return false;
+
+	fwnode_property_read_u32(link,
+				 "intel-quirk-mask",
+				 &quirk_mask);
+
+	if (quirk_mask & SDW_INTEL_QUIRK_MASK_BUS_DISABLE)
+		return false;
+
+	return true;
+}
+
+static int sdw_intel_cleanup(struct sdw_intel_ctx *ctx)
 {
 	struct sdw_intel_link_res *link = ctx->links;
+	struct sdw_master_device *md;
 	int i;
 
 	if (!link)
 		return 0;
 
-	for (i = 0; i < ctx->count; i++) {
-		if (link->pdev)
-			platform_device_unregister(link->pdev);
-		link++;
+	for (i = 0; i < ctx->count; i++, link++) {
+		md = link->md;
+		if (md)
+			md->driver->remove(md);
 	}
 
 	kfree(ctx->links);
@@ -47,112 +72,194 @@ static int sdw_intel_cleanup_pdev(struct sdw_intel_ctx *ctx)
 	return 0;
 }
 
-static struct sdw_intel_ctx
-*sdw_intel_add_controller(struct sdw_intel_res *res)
+static int
+sdw_intel_scan_controller(struct sdw_intel_acpi_info *info)
 {
-	struct platform_device_info pdevinfo;
-	struct platform_device *pdev;
-	struct sdw_intel_link_res *link;
-	struct sdw_intel_ctx *ctx;
 	struct acpi_device *adev;
 	int ret, i;
 	u8 count;
-	u32 caps;
 
-	if (acpi_bus_get_device(res->handle, &adev))
-		return NULL;
+	if (acpi_bus_get_device(info->handle, &adev))
+		return -EINVAL;
 
 	/* Found controller, find links supported */
 	count = 0;
 	ret = fwnode_property_read_u8_array(acpi_fwnode_handle(adev),
 					    "mipi-sdw-master-count", &count, 1);
 
-	/* Don't fail on error, continue and use hw value */
+	/*
+	 * In theory we could check the number of links supported in
+	 * hardware, but in that step we cannot assume SoundWire IP is
+	 * powered.
+	 *
+	 * In addition, if the BIOS doesn't even provide this
+	 * 'master-count' property then all the inits based on link
+	 * masks will fail as well.
+	 *
+	 * We will check the hardware capabilities in the startup() step
+	 */
+
 	if (ret) {
 		dev_err(&adev->dev,
 			"Failed to read mipi-sdw-master-count: %d\n", ret);
-		count = SDW_MAX_LINKS;
+		return -EINVAL;
 	}
 
-	/* Check SNDWLCAP.LCOUNT */
-	caps = ioread32(res->mmio_base + SDW_SHIM_BASE + SDW_SHIM_LCAP);
-	caps &= GENMASK(2, 0);
-
-	/* Check HW supported vs property value and use min of two */
-	count = min_t(u8, caps, count);
-
 	/* Check count is within bounds */
 	if (count > SDW_MAX_LINKS) {
 		dev_err(&adev->dev, "Link count %d exceeds max %d\n",
 			count, SDW_MAX_LINKS);
-		return NULL;
+		return -EINVAL;
 	} else if (!count) {
 		dev_warn(&adev->dev, "No SoundWire links detected\n");
-		return NULL;
+		return -EINVAL;
 	}
+	dev_dbg(&adev->dev, "ACPI reports %d SDW Link devices\n", count);
+
+	info->count = count;
 
+	for (i = 0; i < count; i++) {
+		if (ctrl_link_mask && !(ctrl_link_mask & BIT(i))) {
+			dev_dbg(&adev->dev,
+				"Link %d masked, will not be enabled\n", i);
+			continue;
+		}
+
+		if (!is_link_enabled(acpi_fwnode_handle(adev), i)) {
+			dev_dbg(&adev->dev,
+				"Link %d not selected in firmware\n", i);
+			continue;
+		}
+
+		info->link_mask |= BIT(i);
+	}
+
+	return 0;
+}
+
+static struct sdw_intel_ctx
+*sdw_intel_probe_controller(struct sdw_intel_res *res)
+{
+	struct sdw_intel_link_res *link;
+	struct sdw_intel_ctx *ctx;
+	struct acpi_device *adev;
+	struct sdw_master_device *md;
+	u32 link_mask;
+	int count;
+	int i;
+
+	if (!res)
+		return NULL;
+
+	if (acpi_bus_get_device(res->handle, &adev))
+		return NULL;
+
+	if (!res->count)
+		return NULL;
+
+	count = res->count;
 	dev_dbg(&adev->dev, "Creating %d SDW Link devices\n", count);
 
 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 	if (!ctx)
 		return NULL;
 
-	ctx->count = count;
-	ctx->links = kcalloc(ctx->count, sizeof(*ctx->links), GFP_KERNEL);
+	ctx->links = kcalloc(count, sizeof(*ctx->links), GFP_KERNEL);
 	if (!ctx->links)
 		goto link_err;
 
+	ctx->count = count;
+	ctx->mmio_base = res->mmio_base;
+	ctx->link_mask = res->link_mask;
+	ctx->handle = res->handle;
+
 	link = ctx->links;
+	link_mask = ctx->link_mask;
 
 	/* Create SDW Master devices */
-	for (i = 0; i < count; i++) {
-		if (link_mask && !(link_mask & BIT(i))) {
-			dev_dbg(&adev->dev,
-				"Link %d masked, will not be enabled\n", i);
-			link++;
+	for (i = 0; i < count; i++, link++) {
+		if (link_mask && !(link_mask & BIT(i)))
 			continue;
-		}
 
+		md = sdw_md_add(&intel_sdw_driver,
+				res->parent,
+				acpi_fwnode_handle(adev),
+				i);
+
+		if (IS_ERR(md)) {
+			dev_err(&adev->dev, "Could not create link %d\n", i);
+			goto err;
+		}
+		link->md = md;
+		link->mmio_base = res->mmio_base;
 		link->registers = res->mmio_base + SDW_LINK_BASE
-					+ (SDW_LINK_SIZE * i);
+			+ (SDW_LINK_SIZE * i);
 		link->shim = res->mmio_base + SDW_SHIM_BASE;
 		link->alh = res->mmio_base + SDW_ALH_BASE;
-
+		link->irq = res->irq;
 		link->ops = res->ops;
 		link->dev = res->dev;
 
-		memset(&pdevinfo, 0, sizeof(pdevinfo));
-
-		pdevinfo.parent = res->parent;
-		pdevinfo.name = "int-sdw";
-		pdevinfo.id = i;
-		pdevinfo.fwnode = acpi_fwnode_handle(adev);
-
-		pdev = platform_device_register_full(&pdevinfo);
-		if (IS_ERR(pdev)) {
-			dev_err(&adev->dev,
-				"platform device creation failed: %ld\n",
-				PTR_ERR(pdev));
-			goto pdev_err;
-		}
-
-		link->pdev = pdev;
-		link++;
+		/* let the SoundWire master driver to its probe */
+		md->driver->probe(md, link);
 	}
 
 	return ctx;
 
-pdev_err:
-	sdw_intel_cleanup_pdev(ctx);
+err:
+	sdw_intel_cleanup(ctx);
 link_err:
 	kfree(ctx);
 	return NULL;
 }
 
+static int
+sdw_intel_startup_controller(struct sdw_intel_ctx *ctx)
+{
+	struct acpi_device *adev;
+	struct sdw_intel_link_res *link;
+	struct sdw_master_device *md;
+	u32 caps;
+	u32 link_mask;
+	int i;
+
+	if (acpi_bus_get_device(ctx->handle, &adev))
+		return -EINVAL;
+
+	/* Check SNDWLCAP.LCOUNT */
+	caps = ioread32(ctx->mmio_base + SDW_SHIM_BASE + SDW_SHIM_LCAP);
+	caps &= GENMASK(2, 0);
+
+	/* Check HW supported vs property value */
+	if (caps < ctx->count) {
+		dev_err(&adev->dev,
+			"BIOS master count is larger than hardware capabilities\n");
+		return -EINVAL;
+	}
+
+	if (!ctx->links)
+		return -EINVAL;
+
+	link = ctx->links;
+	link_mask = ctx->link_mask;
+
+	/* Create SDW Master devices */
+	for (i = 0; i < ctx->count; i++, link++) {
+		if (link_mask && !(link_mask & BIT(i)))
+			continue;
+
+		md = link->md;
+
+		md->driver->startup(md);
+	}
+
+	return 0;
+}
+
 static acpi_status sdw_intel_acpi_cb(acpi_handle handle, u32 level,
 				     void *cdata, void **return_value)
 {
-	struct sdw_intel_res *res = cdata;
+	struct sdw_intel_acpi_info *info = cdata;
 	struct acpi_device *adev;
 	acpi_status status;
 	u64 adr;
@@ -166,7 +273,7 @@ static acpi_status sdw_intel_acpi_cb(acpi_handle handle, u32 level,
 		return AE_NOT_FOUND;
 	}
 
-	res->handle = handle;
+	info->handle = handle;
 
 	/*
 	 * On some Intel platforms, multiple children of the HDAS
@@ -183,36 +290,66 @@ static acpi_status sdw_intel_acpi_cb(acpi_handle handle, u32 level,
 }
 
 /**
- * sdw_intel_init() - SoundWire Intel init routine
+ * sdw_intel_acpi_scan() - SoundWire Intel init routine
  * @parent_handle: ACPI parent handle
- * @res: resource data
+ * @info: description of what firmware/DSDT tables expose
  *
- * This scans the namespace and creates SoundWire link controller devices
- * based on the info queried.
+ * This scans the namespace and queries firmware to figure out which
+ * links to enable. A follow-up use of sdw_intel_probe() and
+ * sdw_intel_startup() is required for creation of devices and bus
+ * startup
  */
-void *sdw_intel_init(acpi_handle *parent_handle, struct sdw_intel_res *res)
+int sdw_intel_acpi_scan(acpi_handle *parent_handle,
+			struct sdw_intel_acpi_info *info)
 {
 	acpi_status status;
 
 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
 				     parent_handle, 1,
 				     sdw_intel_acpi_cb,
-				     NULL, res, NULL);
+				     NULL, info, NULL);
 	if (ACPI_FAILURE(status))
-		return NULL;
+		return -ENODEV;
 
-	return sdw_intel_add_controller(res);
+	return sdw_intel_scan_controller(info);
 }
+EXPORT_SYMBOL(sdw_intel_acpi_scan);
 
+/**
+ * sdw_intel_probe() - SoundWire Intel probe routine
+ * @parent_handle: ACPI parent handle
+ * @res: resource data
+ *
+ * This creates SoundWire Master and Slave devices below the controller.
+ * All the information necessary is stored in the context, and the res
+ * argument pointer can be freed after this step.
+ */
+struct sdw_intel_ctx
+*sdw_intel_probe(struct sdw_intel_res *res)
+{
+	return sdw_intel_probe_controller(res);
+}
+EXPORT_SYMBOL(sdw_intel_probe);
+
+/**
+ * sdw_intel_startup() - SoundWire Intel startup
+ * @ctx: SoundWire context allocated in the probe
+ *
+ */
+int sdw_intel_startup(struct sdw_intel_ctx *ctx)
+{
+	return sdw_intel_startup_controller(ctx);
+}
+EXPORT_SYMBOL(sdw_intel_startup);
 /**
  * sdw_intel_exit() - SoundWire Intel exit
- * @arg: callback context
+ * @ctx: SoundWire context allocated in the probe
  *
  * Delete the controller instances created and cleanup
  */
 void sdw_intel_exit(struct sdw_intel_ctx *ctx)
 {
-	sdw_intel_cleanup_pdev(ctx);
+	sdw_intel_cleanup(ctx);
 	kfree(ctx);
 }
 EXPORT_SYMBOL(sdw_intel_exit);
-- 
2.20.1