bus: mhi: core: Indexed MHI controller name

Today the MHI controller name is simply cloned from the underlying
bus device (its parent), that gives the following device structure
for e.g. a MHI/PCI controller:
devices/pci0000:00/0000:00:01.2/0000:02:00.0/0000:02:00.0
devices/pci0000:00/0000:00:01.2/0000:02:00.0/0000:02:00.0/0000:02:00.0_IPCR
...

That's quite misleading/confusing and can cause device registering
issues because of duplicate dev name (e.g. if a PCI device register
two different MHI instances).

This patch changes MHI core to create indexed mhi controller names
(mhi0, mhi1...) in the same way as other busses (i2c0, usb0...).

The previous example becomes:
devices/pci0000:00/0000:00:01.2/0000:02:00.0/mhi0
devices/pci0000:00/0000:00:01.2/0000:02:00.0/mhi0/mhi0_IPCR
...
 v2: move index field at the end of mhi_controller struct (before bool)
     to avoid breaking well packed alignment.
Signed-off-by: NLoic Poulain <loic.poulain@linaro.org>
Reviewed-by: NJeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

drivers/bus/mhi/core/init.c

@@ -8,6 +8,7 @@
 #include <linux/device.h>
 #include <linux/dma-direction.h>
 #include <linux/dma-mapping.h>
+#include <linux/idr.h>
 #include <linux/interrupt.h>
 #include <linux/list.h>
 #include <linux/mhi.h>
@@ -18,6 +19,8 @@
 #include <linux/wait.h>
 #include "internal.h"
 
+static DEFINE_IDA(mhi_controller_ida);
+
 const char * const mhi_ee_str[MHI_EE_MAX] = {
 	[MHI_EE_PBL] = "PBL",
 	[MHI_EE_SBL] = "SBL",
@@ -940,6 +943,12 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
 	mhi_cntrl->minor_version = (soc_info & SOC_HW_VERSION_MINOR_VER_BMSK) >>
 					SOC_HW_VERSION_MINOR_VER_SHFT;
 
+	mhi_cntrl->index = ida_alloc(&mhi_controller_ida, GFP_KERNEL);
+	if (mhi_cntrl->index < 0) {
+		ret = mhi_cntrl->index;
+		goto error_ida_alloc;
+	}
+
 	/* Register controller with MHI bus */
 	mhi_dev = mhi_alloc_device(mhi_cntrl);
 	if (IS_ERR(mhi_dev)) {
@@ -950,8 +959,8 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
 
 	mhi_dev->dev_type = MHI_DEVICE_CONTROLLER;
 	mhi_dev->mhi_cntrl = mhi_cntrl;
-	dev_set_name(&mhi_dev->dev, "%s", dev_name(mhi_cntrl->cntrl_dev));
-	mhi_dev->name = dev_name(mhi_cntrl->cntrl_dev);
+	dev_set_name(&mhi_dev->dev, "mhi%d", mhi_cntrl->index);
+	mhi_dev->name = dev_name(&mhi_dev->dev);
 
 	/* Init wakeup source */
 	device_init_wakeup(&mhi_dev->dev, true);
@@ -970,6 +979,9 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
 	put_device(&mhi_dev->dev);
 
 error_alloc_dev:
+	ida_free(&mhi_controller_ida, mhi_cntrl->index);
+
+error_ida_alloc:
 	kfree(mhi_cntrl->mhi_cmd);
 
 error_alloc_cmd:
@@ -1004,6 +1016,8 @@ void mhi_unregister_controller(struct mhi_controller *mhi_cntrl)
 
 	device_del(&mhi_dev->dev);
 	put_device(&mhi_dev->dev);
+
+	ida_free(&mhi_controller_ida, mhi_cntrl->index);
 }
 EXPORT_SYMBOL_GPL(mhi_unregister_controller);
 

drivers/bus/mhi/core/main.c

@@ -331,7 +331,7 @@ void mhi_create_devices(struct mhi_controller *mhi_cntrl)
 		/* Channel name is same for both UL and DL */
 		mhi_dev->name = mhi_chan->name;
 		dev_set_name(&mhi_dev->dev, "%s_%s",
-			     dev_name(mhi_cntrl->cntrl_dev),
+			     dev_name(&mhi_cntrl->mhi_dev->dev),
 			     mhi_dev->name);
 
 		/* Init wakeup source if available */

include/linux/mhi.h

@@ -348,6 +348,7 @@ struct mhi_controller_config {
  * @read_reg: Read a MHI register via the physical link (required)
  * @write_reg: Write a MHI register via the physical link (required)
  * @buffer_len: Bounce buffer length
+ * @index: Index of the MHI controller instance
  * @bounce_buf: Use of bounce buffer
  * @fbc_download: MHI host needs to do complete image transfer (optional)
  * @pre_init: MHI host needs to do pre-initialization before power up
@@ -438,6 +439,7 @@ struct mhi_controller {
 			  u32 val);
 
 	size_t buffer_len;
+	int index;
 	bool bounce_buf;
 	bool fbc_download;
 	bool pre_init;