Re: [PATCH v2] remoteproc: xilinx: add mailbox channels for rpmsg

From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: Tanmay Shah <tanmays@amd.com>
Cc: "Shah, Tanmay" <tanmay.shah@amd.com>,
	"andersson@kernel.org" <andersson@kernel.org>,
	"linux-remoteproc@vger.kernel.org"
	<linux-remoteproc@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] remoteproc: xilinx: add mailbox channels for rpmsg
Date: Thu, 2 Feb 2023 14:05:41 -0700	[thread overview]
Message-ID: <20230202210541.GA1147631@p14s> (raw)
In-Reply-To: <7cdfb802-ad57-d3ac-c632-88077f2c605f@amd.com>

On Thu, Feb 02, 2023 at 10:17:28AM -0800, Tanmay Shah wrote:
> Hi Mathieu,
> 
> Thanks for reviews.
> 
> Please find my comments below.
> 
> On 1/31/23 2:59 PM, Mathieu Poirier wrote:
> > Good afternoon,
> > 
> > On Thu, Jan 26, 2023 at 01:31:54PM -0800, Tanmay Shah wrote:
> > > This patch makes each r5 core mailbox client and uses
> > > tx and rx channels to send and receive data to/from
> > > remote processor respectively. This is needed for rpmsg
> > > communication to remote processor.
> > > 
> > > Signed-off-by: Tanmay Shah <tanmay.shah@amd.com>
> > > ---
> > > 
> > > Changes in v2:
> > >    - fix vrings carveout names as expeceted by remoteproc framework
> > > 
> > This should be in a patch on its own along with a "Fixes" tag.
> 
> Ack.
> 
> Next time I will send series of two patches.
> 
> First patch to fix vrings name with fixes tag and second patch to add
> mailbox support.
> 
> 
> > 
> > >   drivers/remoteproc/xlnx_r5_remoteproc.c | 352 ++++++++++++++++++++----
> > >   1 file changed, 292 insertions(+), 60 deletions(-)
> > > 
> > > diff --git a/drivers/remoteproc/xlnx_r5_remoteproc.c b/drivers/remoteproc/xlnx_r5_remoteproc.c
> > > index 2db57d394155..45ce7f2089bf 100644
> > > --- a/drivers/remoteproc/xlnx_r5_remoteproc.c
> > > +++ b/drivers/remoteproc/xlnx_r5_remoteproc.c
> > > @@ -8,16 +8,23 @@
> > >   #include <linux/dma-mapping.h>
> > >   #include <linux/firmware/xlnx-zynqmp.h>
> > >   #include <linux/kernel.h>
> > > +#include <linux/mailbox_client.h>
> > > +#include <linux/mailbox/zynqmp-ipi-message.h>
> > >   #include <linux/module.h>
> > >   #include <linux/of_address.h>
> > >   #include <linux/of_platform.h>
> > >   #include <linux/of_reserved_mem.h>
> > >   #include <linux/platform_device.h>
> > >   #include <linux/remoteproc.h>
> > > -#include <linux/slab.h>
> > >   #include "remoteproc_internal.h"
> > > +/* IPI buffer MAX length */
> > > +#define IPI_BUF_LEN_MAX	32U
> > > +
> > The documentation for struct zynqmp_ipi_message clearly states that @data is
> > fixed to 12 bytes, whereas here is it set to 32 bytes.  Wrong documentation or
> > bug?
> 
> As per hardware reference manual, each message buffer is 32-bytes. There
> should be bug in IPI driver documentation.
> 
> I will test this before sending new patch. If 32-bytes are supported, then I
> will send patch to fix IPI driver with fixes tag as well.
> 
> 
> > > +/* RX mailbox client buffer max length */
> > > +#define MBOX_CLIENT_BUF_MAX	(IPI_BUF_LEN_MAX + \
> > > +				 sizeof(struct zynqmp_ipi_message))
> > >   /*
> > >    * settings for RPU cluster mode which
> > >    * reflects possible values of xlnx,cluster-mode dt-property
> > > @@ -65,6 +72,12 @@ static const struct mem_bank_data zynqmp_tcm_banks[] = {
> > >    * @rmem: reserved memory region nodes from device tree
> > >    * @rproc: rproc handle
> > >    * @pm_domain_id: RPU CPU power domain id
> > > + * @rx_mc_buf: to copy data from mailbox rx channel
> > > + * @tx_mc_buf: to copy data to mailbox tx channel
> > > + * @mbox_work: schedule work after receiving data from mailbox
> > > + * @mbox_cl: mailbox client
> > > + * @tx_chan: mailbox tx channel
> > > + * @rx_chan: mailbox rx channel
> > >    */
> > >   struct zynqmp_r5_core {
> > >   	struct device *dev;
> > > @@ -75,6 +88,14 @@ struct zynqmp_r5_core {
> > >   	struct reserved_mem **rmem;
> > >   	struct rproc *rproc;
> > >   	u32 pm_domain_id;
> > > +
> > > +	/* mailbox related data structures */
> > > +	unsigned char rx_mc_buf[MBOX_CLIENT_BUF_MAX];
> > > +	unsigned char tx_mc_buf[MBOX_CLIENT_BUF_MAX];
> > > +	struct work_struct mbox_work;
> > > +	struct mbox_client mbox_cl;
> > > +	struct mbox_chan *tx_chan;
> > > +	struct mbox_chan *rx_chan;
> > >   };
> > >   /**
> > > @@ -92,6 +113,181 @@ struct zynqmp_r5_cluster {
> > >   	struct zynqmp_r5_core **r5_cores;
> > >   };
> > > +/**
> > > + * event_notified_idr_cb() - callback for vq_interrupt per notifyid
> > > + * @id: rproc->notify id
> > > + * @ptr: pointer to idr private data
> > > + * @data: data passed to idr_for_each callback
> > > + *
> > > + * Pass notification to remoteproc virtio
> > > + *
> > > + * Return: 0. having return is to satisfy the idr_for_each() function
> > > + *          pointer input argument requirement.
> > > + **/
> > > +static int event_notified_idr_cb(int id, void *ptr, void *data)
> > > +{
> > > +	struct rproc *rproc = data;
> > > +
> > > +	if (rproc_vq_interrupt(rproc, id) == IRQ_NONE)
> > > +		dev_dbg(&rproc->dev, "data not found for vqid=%d\n", id);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +/**
> > > + * handle_event_notified() - remoteproc notification work function
> > > + * @work: pointer to the work structure
> > > + *
> > > + * It checks each registered remoteproc notify IDs.
> > > + */
> > > +static void handle_event_notified(struct work_struct *work)
> > > +{
> > > +	struct zynqmp_r5_core *r5_core;
> > > +	struct rproc *rproc;
> > > +
> > > +	r5_core = container_of(work, struct zynqmp_r5_core, mbox_work);
> > > +	rproc = r5_core->rproc;
> > > +
> > > +	/*
> > > +	 * We only use IPI for interrupt. The RPU firmware side may or may
> > > +	 * not write the notifyid when it trigger IPI.
> > > +	 * And thus, we scan through all the registered notifyids and
> > > +	 * find which one is valid to get the message.
> > > +	 * Even if message from firmware is NULL, we attempt to get vqid
> > > +	 */
> > > +	idr_for_each(&rproc->notifyids, event_notified_idr_cb, rproc);
> > > +}
> > > +
> > > +/**
> > > + * zynqmp_r5_mb_rx_cb() - receive channel mailbox callback
> > > + * @cl: mailbox client
> > > + * @msg: message pointer
> > > + *
> > > + * Receive data from ipi buffer, ack interrupt and then
> > > + * it will schedule the R5 notification work.
> > > + */
> > > +static void zynqmp_r5_mb_rx_cb(struct mbox_client *cl, void *msg)
> > > +{
> > > +	struct zynqmp_ipi_message *ipi_msg, *buf_msg;
> > > +	struct zynqmp_r5_core *r5_core;
> > > +	size_t len;
> > > +
> > > +	r5_core = container_of(cl, struct zynqmp_r5_core, mbox_cl);
> > > +
> > > +	/* copy data from ipi buffer to r5_core */
> > > +	ipi_msg = (struct zynqmp_ipi_message *)msg;
> > > +	buf_msg = (struct zynqmp_ipi_message *)r5_core->rx_mc_buf;
> > > +	len = ipi_msg->len;
> > > +	if (len > IPI_BUF_LEN_MAX) {
> > > +		dev_warn(r5_core->dev, "msg size exceeded than %d\n",
> > > +			 IPI_BUF_LEN_MAX);
> > > +		len = IPI_BUF_LEN_MAX;
> > > +	}
> > > +	buf_msg->len = len;
> > > +	memcpy(buf_msg->data, ipi_msg->data, len);
> > > +
> > > +	/* received and processed interrupt ack */
> > > +	if (mbox_send_message(r5_core->rx_chan, NULL) < 0)
> > > +		dev_err(r5_core->dev, "ack failed to mbox rx_chan\n");
> > > +
> > > +	schedule_work(&r5_core->mbox_work);
> > > +}
> > > +
> > > +/**
> > > + * zynqmp_r5_setup_mbox() - Setup mailboxes related properties
> > > + *			    this is used for each individual R5 core
> > > + *
> > > + * @r5_core: pointer to the ZynqMP r5 core data
> > > + *
> > > + * Function to setup mailboxes related properties
> > > + *
> > > + */
> > > +static void zynqmp_r5_setup_mbox(struct zynqmp_r5_core *r5_core)
> > > +{
> > > +	struct zynqmp_r5_cluster *cluster;
> > > +	struct mbox_client *mbox_cl;
> > > +
> > > +	cluster = dev_get_drvdata(r5_core->dev->parent);
> > > +
> > > +	/**
> > Extra '*', please remove.
> 
> ACK.
> 
> 
> > 
> > > +	 * ToDo: Use only one IPI channel for APU to communicate with both RPUs
> > > +	 * in split mode. As of now, two IPI channels are expeceted for APU
> > > +	 * to communicate with RPU. for example, APU(IPI0)<-> RPU0(IPI1) and
> > > +	 * APU(IPI7)<->RPU1(IPI2). However, this is not the optimized use
> > > +	 * of the hardware. As per hardware reference manual, each IPI channel
> > > +	 * can receive interrupt from another IPI channel. So APU must be able
> > > +	 * to communicate with both RPUs simultaneously using same IPI channel.
> > > +	 * For example, this is valid case: APU(IPI0)<->RPU0(IPI1) and
> > > +	 * APU(IPI0)<->RPU1(IPI2). However, with current available examples
> > > +	 * and RPU firmware, this configuration in device-tree is causing system-crash.
> > > +	 * And so, using extra IPI channel is required in device-tree. In split
> > > +	 * mode explicitly inform user about this limitation and requirement.
> > > +	 */
> > > +	if (cluster->mode == SPLIT_MODE)
> > > +		dev_warn(r5_core->dev, "split mode: APU should use two IPI channels\n");
> > This comment doesn't do anything useful, please remove.
> 
> 
> ACK.
> 
> 
> > 
> > > +
> > > +	mbox_cl = &r5_core->mbox_cl;
> > > +	mbox_cl->rx_callback = zynqmp_r5_mb_rx_cb;
> > > +	mbox_cl->tx_block = false;
> > > +	mbox_cl->knows_txdone = false;
> > > +	mbox_cl->tx_done = NULL;
> > > +	mbox_cl->dev = r5_core->dev;
> > > +
> > > +	/* Request TX and RX channels */
> > > +	r5_core->tx_chan = mbox_request_channel_byname(mbox_cl, "tx");
> > > +	if (IS_ERR(r5_core->tx_chan)) {
> > > +		r5_core->tx_chan = NULL;
> > > +		return;
> > > +	}
> > > +
> > > +	r5_core->rx_chan = mbox_request_channel_byname(mbox_cl, "rx");
> > > +	if (IS_ERR(r5_core->rx_chan)) {
> > > +		mbox_free_channel(r5_core->tx_chan);
> > > +		r5_core->rx_chan = NULL;
> > > +		r5_core->tx_chan = NULL;
> > > +		return;
> > > +	}
> > > +
> > > +	INIT_WORK(&r5_core->mbox_work, handle_event_notified);
> > > +}
> > > +
> > > +static void zynqmp_r5_free_mbox(struct zynqmp_r5_core *r5_core)
> > > +{
> > > +	if (r5_core->tx_chan) {
> > > +		mbox_free_channel(r5_core->tx_chan);
> > > +		r5_core->tx_chan = NULL;
> > > +	}
> > > +
> > > +	if (r5_core->rx_chan) {
> > > +		mbox_free_channel(r5_core->rx_chan);
> > > +		r5_core->rx_chan = NULL;
> > > +	}
> > > +}
> > > +
> > > +/*
> > > + * zynqmp_r5_core_kick() - kick a firmware if mbox is provided
> > > + * @rproc: r5 core's corresponding rproc structure
> > > + * @vqid: virtqueue ID
> > > + */
> > > +static void zynqmp_r5_rproc_kick(struct rproc *rproc, int vqid)
> > > +{
> > > +	struct zynqmp_r5_core *r5_core = rproc->priv;
> > > +	struct device *dev = r5_core->dev;
> > > +	struct zynqmp_ipi_message *mb_msg;
> > > +	int ret;
> > > +
> > > +	/* don't handle kick if mbox setup failed for this core */
> > > +	if (!r5_core->tx_chan && !r5_core->rx_chan)
> > > +		return;
> > > +
> > > +	mb_msg = (struct zynqmp_ipi_message *)r5_core->tx_mc_buf;
> > > +	memcpy(mb_msg->data, &vqid, sizeof(vqid));
> > > +	mb_msg->len = sizeof(vqid);
> > > +	ret = mbox_send_message(r5_core->tx_chan, mb_msg);
> > > +	if (ret < 0)
> > > +		dev_warn(dev, "failed to send message\n");
> > > +}
> > > +
> > >   /*
> > >    * zynqmp_r5_set_mode()
> > >    *
> > > @@ -227,6 +423,63 @@ static int zynqmp_r5_mem_region_unmap(struct rproc *rproc,
> > >   	return 0;
> > >   }
> > > +/**
> > > + * zynqmp_r5_get_mem_region_node()
> > > + * parse memory-region property and get reserved mem regions
> > > + *
> > > + * @r5_core: pointer to zynqmp_r5_core type object
> > > + *
> > > + * Return: 0 for success and error code for failure.
> > > + */
> > > +static int zynqmp_r5_get_mem_region_node(struct zynqmp_r5_core *r5_core)
> > > +{
> > > +	struct device_node *np, *rmem_np;
> > > +	struct reserved_mem **rmem;
> > > +	int res_mem_count, i;
> > > +	struct device *dev;
> > > +
> > > +	dev = r5_core->dev;
> > > +	np = r5_core->np;
> > > +
> > > +	res_mem_count = of_property_count_elems_of_size(np, "memory-region",
> > > +							sizeof(phandle));
> > > +
> > > +	if (res_mem_count <= 0) {
> > > +		dev_warn(dev, "failed to get memory-region property %d\n",
> > > +			 res_mem_count);
> > > +		return 0;
> > > +	}
> > > +
> > > +	if (!r5_core->tx_chan && !r5_core->rx_chan)
> > > +		res_mem_count = 1;
> > Hackish, please remove.  There should not be a need to mix mailbox information
> > with memory regions.
> 
> ACK.
> 
> 
> > 
> > > +
> > > +	rmem = devm_kcalloc(dev, res_mem_count,
> > > +			    sizeof(struct reserved_mem *), GFP_KERNEL);
> > > +	if (!rmem)
> > > +		return -ENOMEM;
> > > +
> > > +	for (i = 0; i < res_mem_count; i++) {
> > > +		rmem_np = of_parse_phandle(np, "memory-region", i);
> > > +		if (!rmem_np)
> > > +			goto release_rmem;
> > > +
> > > +		rmem[i] = of_reserved_mem_lookup(rmem_np);
> > > +		if (!rmem[i]) {
> > > +			of_node_put(rmem_np);
> > > +			goto release_rmem;
> > > +		}
> > > +
> > > +		of_node_put(rmem_np);
> > > +	}
> > > +
> > > +	r5_core->rmem_count = res_mem_count;
> > > +	r5_core->rmem = rmem;
> > > +	return 0;
> > > +
> > > +release_rmem:
> > > +	return -EINVAL;
> > > +}
> > > +
> > >   /*
> > >    * add_mem_regions_carveout()
> > >    * @rproc: single R5 core's corresponding rproc instance
> > > @@ -241,6 +494,7 @@ static int add_mem_regions_carveout(struct rproc *rproc)
> > >   	struct zynqmp_r5_core *r5_core;
> > >   	struct reserved_mem *rmem;
> > >   	int i, num_mem_regions;
> > > +	const char *name;
> > >   	r5_core = (struct zynqmp_r5_core *)rproc->priv;
> > >   	num_mem_regions = r5_core->rmem_count;
> > > @@ -253,15 +507,33 @@ static int add_mem_regions_carveout(struct rproc *rproc)
> > >   			rproc_mem = rproc_of_resm_mem_entry_init(&rproc->dev, i,
> > >   								 rmem->size,
> > >   								 rmem->base,
> > > -								 rmem->name);
> > > +								 "vdev0buffer");
> > This looks very hackish.
> > 
> > >   		} else {
> > > +			/*
> > > +			 * As per bindings 3rd entry in memory-region property
> > > +			 * must contain vring0 and 4th entry must contain vring1
> > > +			 * memory-regions. For remoteproc framework it is
> > > +			 * required to have fixed names for these carveouts i.e.
> > > +			 * in the form of "vdev%dvring%d" where first %d is ID
> > > +			 * of vdev and second %d is ID of vring. Assign fix names
> > > +			 * instead of node names, as node names may contain
> > > +			 * @unit-address as well i.e. vdev0vring0@xxxxxxxx which
> > > +			 * won't work.
> > > +			 */
> > > +			if (!strncmp(rmem->name, "vdev0vring0", strlen("vdev0vring0")))
> > > +				name = "vdev0vring0";
> > > +			else if (!strncmp(rmem->name, "vdev0vring1", strlen("vdev0vring1")))
> > > +				name = "vdev0vring1";
> > > +			else
> > > +				name = rmem->name;
> > > +
> > So does this.  It would be much better to get the right rmem->name before
> > getting to this function, something that should be done in
> > zynqmp_r5_get_mem_region_node().  Look at stm32_rproc_prepare() for an example
> > on how to get the right name reserve memory entries.
> > 
> > I am also reasonning this problem has become obvious now that mailboxes are
> > working.  That said I also think it should have been caught when the patchset
> > adding support for r5f was worked on.
> 
> Yes correct. Actually I had tested with only one core at a time.
> 
> During testing my device-tree had only node name and not node address (i.e.
> @xxxxxx)
> 
> So, I couldn't catch the issue. Also, mailbox wasn't supported so I couldn't
> put vrings to use at
> 
> that time. I started facing the issue when both cores were up simultaneously
> and I couldn't put
> 
> duplicate node names and I started adding vrings node addresses.
> 
> I will see how to parse node-name only from format "node-name@unit-address".
> 
> That should resolve all above hacks.
> 
> Thanks,
> 
> Tanmay
> 
> 
> > >   			/* Register associated reserved memory regions */
> > >   			rproc_mem = rproc_mem_entry_init(&rproc->dev, NULL,
> > >   							 (dma_addr_t)rmem->base,
> > >   							 rmem->size, rmem->base,
> > >   							 zynqmp_r5_mem_region_map,
> > >   							 zynqmp_r5_mem_region_unmap,
> > > -							 rmem->name);
> > > +							 name);
> > >   		}
> > >   		if (!rproc_mem)
> > > @@ -572,6 +844,20 @@ static int zynqmp_r5_rproc_prepare(struct rproc *rproc)
> > >   		return ret;
> > >   	}
> > > +	/*
> > > +	 * If mailbox nodes are disabled using "status" property then setting up
> > > +	 * mailbox channels will be failed and in that case, we don't need vrings
> > > +	 * and vdevbuffer for this core. So, setup mailbox before parsing
> > > +	 * memory-region property. If "tx" and "rx" mailboxes are not setup, then
> > > +	 * only parse and add first memory-region carveout. As per bindings, it
> > > +	 * must be firmware load region
> > > +	 */
> > > +	zynqmp_r5_setup_mbox(rproc->priv);
> > > +
> > Setting up mailboxes should return an error code when not successful.
> 
> 
> In case of failure that function is printing relative error messages.
> However, If mailbox nodes
> 
> are disabled in device-tree with status property, then it is expected that
> mailbox setup will fail. However,
> 
> that should not stop remoteproc LCM functionality as user still should be
> able to start/stop/loadfw functionality.
> 
> So, I did not see need to return error code.
> 
> I will add return error code, however that won't stop rest of the driver
> functionality. I can just print some warning
> 
> message based on error code.
> 
> 
> >   Moreover,
> > why do mailboxes have to be initialised at prepare() time and not once in the
> > probe() function?
> 
> ACK.
> 
> This part I will take care. I will let you know if I face any problems while
> moving this to probe otherwise I am okay.
> 
> 
> > 
> > > +	ret = zynqmp_r5_get_mem_region_node(rproc->priv);
> > > +	if (ret)
> > > +		dev_warn(&rproc->dev, "memory-region prop failed %d\n", ret);
> > > +
> > >   	ret = add_mem_regions_carveout(rproc);
> > >   	if (ret) {
> > >   		dev_err(&rproc->dev, "failed to get reserve mem regions %d\n", ret);
> > > @@ -597,6 +883,8 @@ static int zynqmp_r5_rproc_unprepare(struct rproc *rproc)
> > >   	r5_core = (struct zynqmp_r5_core *)rproc->priv;
> > > +	zynqmp_r5_free_mbox(r5_core);
> > > +
> > >   	for (i = 0; i < r5_core->tcm_bank_count; i++) {
> > >   		pm_domain_id = r5_core->tcm_banks[i]->pm_domain_id;
> > >   		if (zynqmp_pm_release_node(pm_domain_id))
> > > @@ -617,6 +905,7 @@ static const struct rproc_ops zynqmp_r5_rproc_ops = {
> > >   	.find_loaded_rsc_table = rproc_elf_find_loaded_rsc_table,
> > >   	.sanity_check	= rproc_elf_sanity_check,
> > >   	.get_boot_addr	= rproc_elf_get_boot_addr,
> > > +	.kick		= zynqmp_r5_rproc_kick,
> > A kick() function should added only when mailboxes are present rather than
> > invariably as it is now.
> 
> 
> May be I am missing something but, I believe this is const variable and I
> may not be able to modify it once initialized.
> 
> Is it ok to remove const? then I can take care of adding kick based on mbox
> is available or not.
>

Exactly.  Yes, the "const" can be removed.

> 
> > 
> > >   };
> > >   /**
> > > @@ -726,59 +1015,6 @@ static int zynqmp_r5_get_tcm_node(struct zynqmp_r5_cluster *cluster)
> > >   	return 0;
> > >   }
> > > -/**
> > > - * zynqmp_r5_get_mem_region_node()
> > > - * parse memory-region property and get reserved mem regions
> > > - *
> > > - * @r5_core: pointer to zynqmp_r5_core type object
> > > - *
> > > - * Return: 0 for success and error code for failure.
> > > - */
> > > -static int zynqmp_r5_get_mem_region_node(struct zynqmp_r5_core *r5_core)
> > > -{
> > > -	struct device_node *np, *rmem_np;
> > > -	struct reserved_mem **rmem;
> > > -	int res_mem_count, i;
> > > -	struct device *dev;
> > > -
> > > -	dev = r5_core->dev;
> > > -	np = r5_core->np;
> > > -
> > > -	res_mem_count = of_property_count_elems_of_size(np, "memory-region",
> > > -							sizeof(phandle));
> > > -	if (res_mem_count <= 0) {
> > > -		dev_warn(dev, "failed to get memory-region property %d\n",
> > > -			 res_mem_count);
> > > -		return 0;
> > > -	}
> > > -
> > > -	rmem = devm_kcalloc(dev, res_mem_count,
> > > -			    sizeof(struct reserved_mem *), GFP_KERNEL);
> > > -	if (!rmem)
> > > -		return -ENOMEM;
> > > -
> > > -	for (i = 0; i < res_mem_count; i++) {
> > > -		rmem_np = of_parse_phandle(np, "memory-region", i);
> > > -		if (!rmem_np)
> > > -			goto release_rmem;
> > > -
> > > -		rmem[i] = of_reserved_mem_lookup(rmem_np);
> > > -		if (!rmem[i]) {
> > > -			of_node_put(rmem_np);
> > > -			goto release_rmem;
> > > -		}
> > > -
> > > -		of_node_put(rmem_np);
> > > -	}
> > > -
> > > -	r5_core->rmem_count = res_mem_count;
> > > -	r5_core->rmem = rmem;
> > > -	return 0;
> > > -
> > > -release_rmem:
> > > -	return -EINVAL;
> > > -}
> > > -
> > Why was this moved instead of simply adding a forward declaration at the top of
> > the file?
> 
> 
> ACK. That's good idea. Thanks!
> 
> 
> > 
> > >   /*
> > >    * zynqmp_r5_core_init()
> > >    * Create and initialize zynqmp_r5_core type object
> > > @@ -806,10 +1042,6 @@ static int zynqmp_r5_core_init(struct zynqmp_r5_cluster *cluster,
> > >   	for (i = 0; i < cluster->core_count; i++) {
> > >   		r5_core = cluster->r5_cores[i];
> > > -		ret = zynqmp_r5_get_mem_region_node(r5_core);
> > > -		if (ret)
> > > -			dev_warn(dev, "memory-region prop failed %d\n", ret);
> > > -
> > Why doing this since this driver doesn't support attach()/detach() operations
> > yet?
> 
> 
> I see, so we should always fail if memory-region property isn't defined?

My comment is about moving zynqmp_r5_get_mem_region_node() to the prepare()
function.  There shouldn't be a need to do that.

> 
> Actually it is also possible to load and boot firmware completely out of
> TCM.
> 
> Since the driver has TCM addresses, we don't really need memory-region
> property at all in
> 
> that case. So by not failing when memory-region is not defined, we are
> giving chance to
> 
> load and boot firmware from TCM. I can add this in comment.
> 
> Thanks,
> 
> Tanmay
> 
> 
> > Thanks,
> > Mathieu
> > 
> > >   		/* Initialize r5 cores with power-domains parsed from dts */
> > >   		ret = of_property_read_u32_index(r5_core->np, "power-domains",
> > >   						 1, &r5_core->pm_domain_id);
> > > 
> > > base-commit: 10de8156ed71d3dbd7e9099aa76e67ea2c37d4ff
> > > -- 
> > > 2.25.1
> > > 