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Message-ID: <b66e8bbe-8228-401a-9bb8-848b2d132ca0@ti.com>
Date: Wed, 8 May 2024 10:36:50 -0500
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Subject: Re: [PATCH v9 2/5] remoteproc: k3-m4: Add a remoteproc driver for M4F
 subsystem
To: Mathieu Poirier <mathieu.poirier@linaro.org>
CC: Bjorn Andersson <andersson@kernel.org>, Rob Herring <robh@kernel.org>,
        Krzysztof Kozlowski <krzk+dt@kernel.org>,
        Conor Dooley <conor+dt@kernel.org>, Nishanth Menon <nm@ti.com>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Tero
 Kristo <kristo@kernel.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Hari
 Nagalla <hnagalla@ti.com>, <linux-remoteproc@vger.kernel.org>,
        <devicetree@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>
References: <20240426191811.32414-1-afd@ti.com>
 <20240426191811.32414-3-afd@ti.com> <ZjlBrf2mxENSZb8E@p14s>
Content-Language: en-US
From: Andrew Davis <afd@ti.com>
In-Reply-To: <ZjlBrf2mxENSZb8E@p14s>
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On 5/6/24 3:46 PM, Mathieu Poirier wrote:
> Good day,
> 
> I have started reviewing this patchset.  Comments will be scattered over
> multiple days and as such, I will explicitly inform you when  am done with the
> review.
> 
> On Fri, Apr 26, 2024 at 02:18:08PM -0500, Andrew Davis wrote:
>> From: Martyn Welch <martyn.welch@collabora.com>
>>
>> The AM62x and AM64x SoCs of the TI K3 family has a Cortex M4F core in
>> the MCU domain. This core is typically used for safety applications in a
>> stand alone mode. However, some application (non safety related) may
>> want to use the M4F core as a generic remote processor with IPC to the
>> host processor. The M4F core has internal IRAM and DRAM memories and are
>> exposed to the system bus for code and data loading.
>>
>> A remote processor driver is added to support this subsystem, including
>> being able to load and boot the M4F core. Loading includes to M4F
>> internal memories and predefined external code/data memories. The
>> carve outs for external contiguous memory is defined in the M4F device
>> node and should match with the external memory declarations in the M4F
>> image binary. The M4F subsystem has two resets. One reset is for the
>> entire subsystem i.e including the internal memories and the other, a
>> local reset is only for the M4F processing core. When loading the image,
>> the driver first releases the subsystem reset, loads the firmware image
>> and then releases the local reset to let the M4F processing core run.
>>
>> Signed-off-by: Martyn Welch <martyn.welch@collabora.com>
>> Signed-off-by: Hari Nagalla <hnagalla@ti.com>
>> Signed-off-by: Andrew Davis <afd@ti.com>
>> ---
>>   drivers/remoteproc/Kconfig               |  13 +
>>   drivers/remoteproc/Makefile              |   1 +
>>   drivers/remoteproc/ti_k3_m4_remoteproc.c | 785 +++++++++++++++++++++++
>>   3 files changed, 799 insertions(+)
>>   create mode 100644 drivers/remoteproc/ti_k3_m4_remoteproc.c
>>
>> diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
>> index 48845dc8fa852..1a7c0330c91a9 100644
>> --- a/drivers/remoteproc/Kconfig
>> +++ b/drivers/remoteproc/Kconfig
>> @@ -339,6 +339,19 @@ config TI_K3_DSP_REMOTEPROC
>>   	  It's safe to say N here if you're not interested in utilizing
>>   	  the DSP slave processors.
>>   
>> +config TI_K3_M4_REMOTEPROC
>> +	tristate "TI K3 M4 remoteproc support"
>> +	depends on ARCH_K3 || COMPILE_TEST
>> +	select MAILBOX
>> +	select OMAP2PLUS_MBOX
>> +	help
>> +	  Say m here to support TI's M4 remote processor subsystems
>> +	  on various TI K3 family of SoCs through the remote processor
>> +	  framework.
>> +
>> +	  It's safe to say N here if you're not interested in utilizing
>> +	  a remote processor.
>> +
>>   config TI_K3_R5_REMOTEPROC
>>   	tristate "TI K3 R5 remoteproc support"
>>   	depends on ARCH_K3
>> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
>> index 91314a9b43cef..5ff4e2fee4abd 100644
>> --- a/drivers/remoteproc/Makefile
>> +++ b/drivers/remoteproc/Makefile
>> @@ -37,5 +37,6 @@ obj-$(CONFIG_ST_REMOTEPROC)		+= st_remoteproc.o
>>   obj-$(CONFIG_ST_SLIM_REMOTEPROC)	+= st_slim_rproc.o
>>   obj-$(CONFIG_STM32_RPROC)		+= stm32_rproc.o
>>   obj-$(CONFIG_TI_K3_DSP_REMOTEPROC)	+= ti_k3_dsp_remoteproc.o
>> +obj-$(CONFIG_TI_K3_M4_REMOTEPROC)	+= ti_k3_m4_remoteproc.o
>>   obj-$(CONFIG_TI_K3_R5_REMOTEPROC)	+= ti_k3_r5_remoteproc.o
>>   obj-$(CONFIG_XLNX_R5_REMOTEPROC)	+= xlnx_r5_remoteproc.o
>> diff --git a/drivers/remoteproc/ti_k3_m4_remoteproc.c b/drivers/remoteproc/ti_k3_m4_remoteproc.c
>> new file mode 100644
>> index 0000000000000..0030e509f6b5d
>> --- /dev/null
>> +++ b/drivers/remoteproc/ti_k3_m4_remoteproc.c
>> @@ -0,0 +1,785 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * TI K3 Cortex-M4 Remote Processor(s) driver
>> + *
>> + * Copyright (C) 2021-2024 Texas Instruments Incorporated - https://www.ti.com/
>> + *	Hari Nagalla <hnagalla@ti.com>
>> + */
>> +
>> +#include <linux/io.h>
>> +#include <linux/mailbox_client.h>
>> +#include <linux/module.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_reserved_mem.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/remoteproc.h>
>> +#include <linux/reset.h>
>> +#include <linux/slab.h>
>> +
>> +#include "omap_remoteproc.h"
>> +#include "remoteproc_internal.h"
>> +#include "ti_sci_proc.h"
>> +
>> +/**
>> + * struct k3_m4_rproc_mem - internal memory structure
>> + * @cpu_addr: MPU virtual address of the memory region
>> + * @bus_addr: Bus address used to access the memory region
>> + * @dev_addr: Device address of the memory region from remote processor view
>> + * @size: Size of the memory region
>> + */
>> +struct k3_m4_rproc_mem {
>> +	void __iomem *cpu_addr;
>> +	phys_addr_t bus_addr;
>> +	u32 dev_addr;
>> +	size_t size;
>> +};
>> +
>> +/**
>> + * struct k3_m4_rproc_mem_data - memory definitions for a remote processor
>> + * @name: name for this memory entry
>> + * @dev_addr: device address for the memory entry
>> + */
>> +struct k3_m4_rproc_mem_data {
>> +	const char *name;
>> +	const u32 dev_addr;
>> +};
>> +
>> +/**
>> + * struct k3_m4_rproc_dev_data - device data structure for a remote processor
>> + * @mems: pointer to memory definitions for a remote processor
>> + * @num_mems: number of memory regions in @mems
>> + * @uses_lreset: flag to denote the need for local reset management
>> + */
>> +struct k3_m4_rproc_dev_data {
>> +	const struct k3_m4_rproc_mem_data *mems;
>> +	u32 num_mems;
>> +	bool uses_lreset;
>> +};
>> +
>> +/**
>> + * struct k3_m4_rproc - k3 remote processor driver structure
>> + * @dev: cached device pointer
>> + * @rproc: remoteproc device handle
>> + * @mem: internal memory regions data
>> + * @num_mems: number of internal memory regions
>> + * @rmem: reserved memory regions data
>> + * @num_rmems: number of reserved memory regions
>> + * @reset: reset control handle
>> + * @data: pointer to device data
>> + * @tsp: TI-SCI processor control handle
>> + * @ti_sci: TI-SCI handle
>> + * @ti_sci_id: TI-SCI device identifier
>> + * @mbox: mailbox channel handle
>> + * @client: mailbox client to request the mailbox channel
>> + */
>> +struct k3_m4_rproc {
>> +	struct device *dev;
>> +	struct rproc *rproc;
>> +	struct k3_m4_rproc_mem *mem;
>> +	int num_mems;
>> +	struct k3_m4_rproc_mem *rmem;
>> +	int num_rmems;
>> +	struct reset_control *reset;
>> +	const struct k3_m4_rproc_dev_data *data;
>> +	struct ti_sci_proc *tsp;
>> +	const struct ti_sci_handle *ti_sci;
>> +	u32 ti_sci_id;
>> +	struct mbox_chan *mbox;
>> +	struct mbox_client client;
>> +};
>> +
>> +/**
>> + * k3_m4_rproc_mbox_callback() - inbound mailbox message handler
>> + * @client: mailbox client pointer used for requesting the mailbox channel
>> + * @data: mailbox payload
>> + *
>> + * This handler is invoked by the K3 mailbox driver whenever a mailbox
>> + * message is received. Usually, the mailbox payload simply contains
>> + * the index of the virtqueue that is kicked by the remote processor,
>> + * and we let remoteproc core handle it.
>> + *
>> + * In addition to virtqueue indices, we also have some out-of-band values
>> + * that indicate different events. Those values are deliberately very
>> + * large so they don't coincide with virtqueue indices.
>> + */
>> +static void k3_m4_rproc_mbox_callback(struct mbox_client *client, void *data)
>> +{
>> +	struct k3_m4_rproc *kproc = container_of(client, struct k3_m4_rproc,
>> +						  client);
>> +	struct device *dev = kproc->rproc->dev.parent;
>> +	const char *name = kproc->rproc->name;
>> +	u32 msg = (u32)(uintptr_t)(data);
>> +
>> +	dev_dbg(dev, "mbox msg: 0x%x\n", msg);
>> +
>> +	switch (msg) {
>> +	case RP_MBOX_CRASH:
>> +		/*
>> +		 * remoteproc detected an exception, but error recovery is not
>> +		 * supported. So, just log this for now
>> +		 */
>> +		dev_err(dev, "K3 rproc %s crashed\n", name);
>> +		break;
>> +	case RP_MBOX_ECHO_REPLY:
>> +		dev_info(dev, "received echo reply from %s\n", name);
>> +		break;
>> +	default:
>> +		/* silently handle all other valid messages */
>> +		if (msg >= RP_MBOX_READY && msg < RP_MBOX_END_MSG)
>> +			return;
>> +		if (msg > kproc->rproc->max_notifyid) {
>> +			dev_dbg(dev, "dropping unknown message 0x%x", msg);
>> +			return;
>> +		}
>> +		/* msg contains the index of the triggered vring */
>> +		if (rproc_vq_interrupt(kproc->rproc, msg) == IRQ_NONE)
>> +			dev_dbg(dev, "no message was found in vqid %d\n", msg);
>> +	}
>> +}
>> +
>> +/*
>> + * Kick the remote processor to notify about pending unprocessed messages.
>> + * The vqid usage is not used and is inconsequential, as the kick is performed
>> + * through a simulated GPIO (a bit in an IPC interrupt-triggering register),
>> + * the remote processor is expected to process both its Tx and Rx virtqueues.
>> + */
>> +static void k3_m4_rproc_kick(struct rproc *rproc, int vqid)
>> +{
>> +	struct k3_m4_rproc *kproc = rproc->priv;
>> +	struct device *dev = rproc->dev.parent;
>> +	u32 msg = (u32)vqid;
>> +	int ret;
>> +
>> +	/* send the index of the triggered virtqueue in the mailbox payload */
>> +	ret = mbox_send_message(kproc->mbox, (void *)(uintptr_t)msg);
>> +	if (ret < 0)
>> +		dev_err(dev, "failed to send mailbox message, status = %d\n",
>> +			ret);
>> +}
>> +
>> +/* Put the remote processor into reset */
>> +static int k3_m4_rproc_reset(struct k3_m4_rproc *kproc)
>> +{
>> +	struct device *dev = kproc->dev;
>> +	int ret;
>> +
>> +	ret = reset_control_assert(kproc->reset);
>> +	if (ret) {
>> +		dev_err(dev, "local-reset assert failed, ret = %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	if (kproc->data->uses_lreset)
>> +		return ret;
>> +
>> +	ret = kproc->ti_sci->ops.dev_ops.put_device(kproc->ti_sci,
>> +						    kproc->ti_sci_id);
>> +	if (ret) {
>> +		dev_err(dev, "module-reset assert failed, ret = %d\n", ret);
>> +		if (reset_control_deassert(kproc->reset))
>> +			dev_warn(dev, "local-reset deassert back failed\n");
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +/* Release the remote processor from reset */
>> +static int k3_m4_rproc_release(struct k3_m4_rproc *kproc)
>> +{
>> +	struct device *dev = kproc->dev;
>> +	int ret;
>> +
>> +	if (kproc->data->uses_lreset)
>> +		goto lreset;
>> +
>> +	ret = kproc->ti_sci->ops.dev_ops.get_device(kproc->ti_sci,
>> +						    kproc->ti_sci_id);
>> +	if (ret) {
>> +		dev_err(dev, "module-reset deassert failed, ret = %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +lreset:
>> +	ret = reset_control_deassert(kproc->reset);
>> +	if (ret) {
>> +		dev_err(dev, "local-reset deassert failed, ret = %d\n", ret);
>> +		if (kproc->ti_sci->ops.dev_ops.put_device(kproc->ti_sci,
>> +							  kproc->ti_sci_id))
>> +			dev_warn(dev, "module-reset assert back failed\n");
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static int k3_m4_rproc_request_mbox(struct rproc *rproc)
>> +{
>> +	struct k3_m4_rproc *kproc = rproc->priv;
>> +	struct mbox_client *client = &kproc->client;
>> +	struct device *dev = kproc->dev;
>> +	int ret;
>> +
>> +	client->dev = dev;
>> +	client->tx_done = NULL;
>> +	client->rx_callback = k3_m4_rproc_mbox_callback;
>> +	client->tx_block = false;
>> +	client->knows_txdone = false;
>> +
>> +	kproc->mbox = mbox_request_channel(client, 0);
>> +	if (IS_ERR(kproc->mbox)) {
>> +		ret = -EBUSY;
>> +		dev_err(dev, "mbox_request_channel failed: %ld\n",
>> +			PTR_ERR(kproc->mbox));
>> +		return ret;
>> +	}
>> +
>> +	/*
>> +	 * Ping the remote processor, this is only for sanity-sake for now;
>> +	 * there is no functional effect whatsoever.
>> +	 *
>> +	 * Note that the reply will _not_ arrive immediately: this message
>> +	 * will wait in the mailbox fifo until the remote processor is booted.
>> +	 */
>> +	ret = mbox_send_message(kproc->mbox, (void *)RP_MBOX_ECHO_REQUEST);
>> +	if (ret < 0) {
>> +		dev_err(dev, "mbox_send_message failed: %d\n", ret);
>> +		mbox_free_channel(kproc->mbox);
>> +		return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +/*
>> + * The M4 cores have a local reset that affects only the CPU, and a
>> + * generic module reset that powers on the device and allows the internal
>> + * memories to be accessed while the local reset is asserted. This function is
>> + * used to release the global reset on remote cores to allow loading into the
>> + * internal RAMs. The .prepare() ops is invoked by remoteproc core before any
>> + * firmware loading, and is followed by the .start() ops after loading to
>> + * actually let the remote cores to run. This callback is invoked only in
>> + * remoteproc mode.
>> + */
>> +static int k3_m4_rproc_prepare(struct rproc *rproc)
>> +{
>> +	struct k3_m4_rproc *kproc = rproc->priv;
>> +	struct device *dev = kproc->dev;
>> +	int ret;
>> +
>> +	ret = kproc->ti_sci->ops.dev_ops.get_device(kproc->ti_sci,
>> +						    kproc->ti_sci_id);
>> +	if (ret)
>> +		dev_err(dev, "module-reset deassert failed, cannot enable internal RAM loading, ret = %d\n",
>> +			ret);
>> +
>> +	return ret;
>> +}
>> +
>> +/*
>> + * This function implements the .unprepare() ops and performs the complimentary
>> + * operations to that of the .prepare() ops. The function is used to assert the
>> + * global reset on applicable cores. This completes the second portion of
>> + * powering down the remote core. The cores themselves are only halted in the
>> + * .stop() callback through the local reset, and the .unprepare() ops is invoked
>> + * by the remoteproc core after the remoteproc is stopped to balance the global
>> + * reset. This callback is invoked only in remoteproc mode.
>> + */
>> +static int k3_m4_rproc_unprepare(struct rproc *rproc)
>> +{
>> +	struct k3_m4_rproc *kproc = rproc->priv;
>> +	struct device *dev = kproc->dev;
>> +	int ret;
>> +
>> +	ret = kproc->ti_sci->ops.dev_ops.put_device(kproc->ti_sci,
>> +						    kproc->ti_sci_id);
>> +	if (ret)
>> +		dev_err(dev, "module-reset assert failed, ret = %d\n", ret);
>> +
>> +	return ret;
>> +}
>> +
>> +/*
>> + * This function implements the .get_loaded_rsc_table() callback and is used
>> + * to provide the resource table for a booted remote processor in IPC-only
>> + * mode. The remote processor firmwares follow a design-by-contract approach
>> + * and are expected to have the resource table at the base of the DDR region
>> + * reserved for firmware usage. This provides flexibility for the remote
>> + * processor to be booted by different bootloaders that may or may not have the
>> + * ability to publish the resource table address and size through a DT
>> + * property.
>> + */
>> +static struct resource_table *k3_m4_get_loaded_rsc_table(struct rproc *rproc,
>> +							 size_t *rsc_table_sz)
>> +{
>> +	struct k3_m4_rproc *kproc = rproc->priv;
>> +	struct device *dev = kproc->dev;
>> +
>> +	if (!kproc->rmem[0].cpu_addr) {
>> +		dev_err(dev, "memory-region #1 does not exist, loaded rsc table can't be found");
>> +		return ERR_PTR(-ENOMEM);
>> +	}
>> +
>> +	/*
>> +	 * NOTE: The resource table size is currently hard-coded to a maximum
>> +	 * of 256 bytes. The most common resource table usage for K3 firmwares
>> +	 * is to only have the vdev resource entry and an optional trace entry.
>> +	 * The exact size could be computed based on resource table address, but
>> +	 * the hard-coded value suffices to support the IPC-only mode.
>> +	 */
>> +	*rsc_table_sz = 256;
>> +	return (__force struct resource_table *)kproc->rmem[0].cpu_addr;
>> +}
>> +
>> +/*
>> + * Custom function to translate a remote processor device address (internal
>> + * RAMs only) to a kernel virtual address.  The remote processors can access
>> + * their RAMs at either an internal address visible only from a remote
>> + * processor, or at the SoC-level bus address. Both these addresses need to be
>> + * looked through for translation. The translated addresses can be used either
>> + * by the remoteproc core for loading (when using kernel remoteproc loader), or
>> + * by any rpmsg bus drivers.
>> + */
>> +static void *k3_m4_rproc_da_to_va(struct rproc *rproc, u64 da, size_t len, bool *is_iomem)
>> +{
>> +	struct k3_m4_rproc *kproc = rproc->priv;
>> +	void __iomem *va = NULL;
>> +	phys_addr_t bus_addr;
>> +	u32 dev_addr, offset;
>> +	size_t size;
>> +	int i;
>> +
>> +	if (len == 0)
>> +		return NULL;
>> +
>> +	for (i = 0; i < kproc->num_mems; i++) {
>> +		bus_addr = kproc->mem[i].bus_addr;
>> +		dev_addr = kproc->mem[i].dev_addr;
>> +		size = kproc->mem[i].size;
>> +
>> +		/* handle M4-view addresses */
>> +		if (da >= dev_addr && ((da + len) <= (dev_addr + size))) {
>> +			offset = da - dev_addr;
>> +			va = kproc->mem[i].cpu_addr + offset;
>> +			return (__force void *)va;
>> +		}
>> +
>> +		/* handle SoC-view addresses */
>> +		if (da >= bus_addr && ((da + len) <= (bus_addr + size))) {
>> +			offset = da - bus_addr;
>> +			va = kproc->mem[i].cpu_addr + offset;
>> +			return (__force void *)va;
>> +		}
>> +	}
>> +
>> +	/* handle static DDR reserved memory regions */
>> +	for (i = 0; i < kproc->num_rmems; i++) {
>> +		dev_addr = kproc->rmem[i].dev_addr;
>> +		size = kproc->rmem[i].size;
>> +
>> +		if (da >= dev_addr && ((da + len) <= (dev_addr + size))) {
>> +			offset = da - dev_addr;
>> +			va = kproc->rmem[i].cpu_addr + offset;
>> +			return (__force void *)va;
>> +		}
>> +	}
>> +
>> +	return NULL;
>> +}
>> +
>> +static int k3_m4_rproc_of_get_memories(struct platform_device *pdev,
>> +				       struct k3_m4_rproc *kproc)
>> +{
>> +	const struct k3_m4_rproc_dev_data *data = kproc->data;
>> +	struct device *dev = &pdev->dev;
>> +	struct resource *res;
>> +	int num_mems = 0;
>> +	int i;
>> +
>> +	num_mems = kproc->data->num_mems;
>> +	kproc->mem = devm_kcalloc(kproc->dev, num_mems,
>> +				  sizeof(*kproc->mem), GFP_KERNEL);
>> +	if (!kproc->mem)
>> +		return -ENOMEM;
>> +
>> +	for (i = 0; i < num_mems; i++) {
>> +		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>> +						   data->mems[i].name);
>> +		if (!res) {
>> +			dev_err(dev, "found no memory resource for %s\n",
>> +				data->mems[i].name);
>> +			return -EINVAL;
>> +		}
>> +		if (!devm_request_mem_region(dev, res->start,
>> +					     resource_size(res),
>> +					     dev_name(dev))) {
>> +			dev_err(dev, "could not request %s region for resource\n",
>> +				data->mems[i].name);
>> +			return -EBUSY;
>> +		}
>> +
>> +		kproc->mem[i].cpu_addr = devm_ioremap_wc(dev, res->start,
>> +							 resource_size(res));
>> +		if (!kproc->mem[i].cpu_addr) {
>> +			dev_err(dev, "failed to map %s memory\n",
>> +				data->mems[i].name);
>> +			return -ENOMEM;
>> +		}
>> +		kproc->mem[i].bus_addr = res->start;
>> +		kproc->mem[i].dev_addr = data->mems[i].dev_addr;
>> +		kproc->mem[i].size = resource_size(res);
>> +
>> +		dev_dbg(dev, "memory %8s: bus addr %pa size 0x%zx va %pK da 0x%x\n",
>> +			data->mems[i].name, &kproc->mem[i].bus_addr,
>> +			kproc->mem[i].size, kproc->mem[i].cpu_addr,
>> +			kproc->mem[i].dev_addr);
>> +	}
>> +	kproc->num_mems = num_mems;
>> +
>> +	return 0;
>> +}
>> +
>> +static void k3_m4_rproc_dev_mem_release(void *data)
>> +{
>> +	struct device *dev = data;
>> +
>> +	of_reserved_mem_device_release(dev);
>> +}
>> +
>> +static int k3_m4_reserved_mem_init(struct k3_m4_rproc *kproc)
>> +{
>> +	struct device *dev = kproc->dev;
>> +	struct device_node *np = dev->of_node;
>> +	struct device_node *rmem_np;
>> +	struct reserved_mem *rmem;
>> +	int num_rmems;
>> +	int ret, i;
>> +
>> +	num_rmems = of_property_count_elems_of_size(np, "memory-region",
>> +						    sizeof(phandle));
>> +	if (num_rmems < 0) {
>> +		dev_err(dev, "device does not reserved memory regions (%pe)\n",
>> +			ERR_PTR(num_rmems));
>> +		return -EINVAL;
>> +	}
>> +	if (num_rmems < 2) {
>> +		dev_err(dev, "device needs at least two memory regions to be defined, num = %d\n",
>> +			num_rmems);
>> +		return -EINVAL;
>> +	}
>> +
>> +	/* use reserved memory region 0 for vring DMA allocations */
>> +	ret = of_reserved_mem_device_init_by_idx(dev, np, 0);
>> +	if (ret) {
>> +		dev_err(dev, "device cannot initialize DMA pool (%pe)\n",
>> +			ERR_PTR(ret));
>> +		return ret;
>> +	}
>> +	ret = devm_add_action_or_reset(dev, k3_m4_rproc_dev_mem_release, dev);
>> +	if (ret)
>> +		return ret;
>> +
>> +	num_rmems--;
>> +	kproc->rmem = devm_kcalloc(dev, num_rmems, sizeof(*kproc->rmem), GFP_KERNEL);
>> +	if (!kproc->rmem)
>> +		return -ENOMEM;
>> +
>> +	/* use remaining reserved memory regions for static carveouts */
>> +	for (i = 0; i < num_rmems; i++) {
>> +		rmem_np = of_parse_phandle(np, "memory-region", i + 1);
>> +		if (!rmem_np)
>> +			return -EINVAL;
>> +
>> +		rmem = of_reserved_mem_lookup(rmem_np);
>> +		if (!rmem) {
>> +			of_node_put(rmem_np);
>> +			return -EINVAL;
>> +		}
>> +		of_node_put(rmem_np);
>> +
>> +		kproc->rmem[i].bus_addr = rmem->base;
>> +		/* 64-bit address regions currently not supported */
>> +		kproc->rmem[i].dev_addr = (u32)rmem->base;
>> +		kproc->rmem[i].size = rmem->size;
>> +		kproc->rmem[i].cpu_addr = devm_ioremap_wc(dev, rmem->base, rmem->size);
>> +		if (!kproc->rmem[i].cpu_addr) {
>> +			dev_err(dev, "failed to map reserved memory#%d at %pa of size %pa\n",
>> +				i + 1, &rmem->base, &rmem->size);
>> +			return -ENOMEM;
>> +		}
>> +
>> +		dev_dbg(dev, "reserved memory%d: bus addr %pa size 0x%zx va %pK da 0x%x\n",
>> +			i + 1, &kproc->rmem[i].bus_addr,
>> +			kproc->rmem[i].size, kproc->rmem[i].cpu_addr,
>> +			kproc->rmem[i].dev_addr);
>> +	}
>> +	kproc->num_rmems = num_rmems;
>> +
>> +	return 0;
>> +}
>> +
>> +static struct ti_sci_proc *k3_m4_rproc_of_get_tsp(struct device *dev,
>> +						  const struct ti_sci_handle *sci)
>> +{
>> +	struct ti_sci_proc *tsp;
>> +	u32 temp[2];
>> +	int ret;
>> +
>> +	ret = of_property_read_u32_array(dev->of_node, "ti,sci-proc-ids",
>> +					 temp, 2);
>> +	if (ret < 0)
>> +		return ERR_PTR(ret);
>> +
>> +	tsp = devm_kzalloc(dev, sizeof(*tsp), GFP_KERNEL);
>> +	if (!tsp)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	tsp->dev = dev;
>> +	tsp->sci = sci;
>> +	tsp->ops = &sci->ops.proc_ops;
>> +	tsp->proc_id = temp[0];
>> +	tsp->host_id = temp[1];
>> +
>> +	return tsp;
>> +}
>> +
>> +static void k3_m4_release_tsp(void *data)
>> +{
>> +	struct ti_sci_proc *tsp = data;
>> +
>> +	ti_sci_proc_release(tsp);
>> +}
>> +
>> +/*
>> + * Power up the M4F remote processor.
>> + *
>> + * This function will be invoked only after the firmware for this rproc
>> + * was loaded, parsed successfully, and all of its resource requirements
>> + * were met. This callback is invoked only in remoteproc mode.
>> + */
>> +static int k3_m4_rproc_start(struct rproc *rproc)
>> +{
>> +	struct k3_m4_rproc *kproc = rproc->priv;
>> +	int ret;
>> +
>> +	ret = k3_m4_rproc_request_mbox(rproc);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = k3_m4_rproc_release(kproc);
>> +	if (ret)
>> +		goto put_mbox;
>> +
>> +	return 0;
>> +
>> +put_mbox:
>> +	mbox_free_channel(kproc->mbox);
>> +	return ret;
>> +}
>> +
>> +/*
>> + * Stop the M4 remote processor.
>> + *
>> + * This function puts the M4 processor into reset, and finishes processing
>> + * of any pending messages. This callback is invoked only in remoteproc mode.
>> + */
>> +static int k3_m4_rproc_stop(struct rproc *rproc)
>> +{
>> +	struct k3_m4_rproc *kproc = rproc->priv;
>> +
>> +	mbox_free_channel(kproc->mbox);
>> +
>> +	k3_m4_rproc_reset(kproc);
>> +
>> +	return 0;
>> +}
>> +
>> +/*
>> + * Attach to a running M4 remote processor (IPC-only mode)
>> + *
>> + * This rproc attach callback only needs to request the mailbox, the remote
>> + * processor is already booted, so there is no need to issue any TI-SCI
>> + * commands to boot the M4 core. This callback is used only in IPC-only mode.
>> + */
>> +static int k3_m4_rproc_attach(struct rproc *rproc)
>> +{
>> +	struct k3_m4_rproc *kproc = rproc->priv;
>> +	struct device *dev = kproc->dev;
>> +	int ret;
>> +
>> +	ret = k3_m4_rproc_request_mbox(rproc);
>> +	if (ret)
>> +		return ret;
>> +
>> +	dev_info(dev, "M4 initialized in IPC-only mode\n");
>> +	return 0;
>> +}
>> +
>> +/*
>> + * Detach from a running M4 remote processor (IPC-only mode)
>> + *
>> + * This rproc detach callback performs the opposite operation to attach callback
>> + * and only needs to release the mailbox, the M4 core is not stopped and will
>> + * be left to continue to run its booted firmware. This callback is invoked only in
>> + * IPC-only mode.
>> + */
>> +static int k3_m4_rproc_detach(struct rproc *rproc)
>> +{
>> +	struct k3_m4_rproc *kproc = rproc->priv;
>> +	struct device *dev = kproc->dev;
>> +
>> +	mbox_free_channel(kproc->mbox);
>> +	dev_info(dev, "M4 deinitialized in IPC-only mode\n");
>> +	return 0;
>> +}
>> +
>> +static const struct rproc_ops k3_m4_rproc_ops = {
>> +	.start		= k3_m4_rproc_start,
>> +	.stop		= k3_m4_rproc_stop,
>> +	.attach		= k3_m4_rproc_attach,
>> +	.detach		= k3_m4_rproc_detach,
>> +	.kick		= k3_m4_rproc_kick,
>> +	.da_to_va	= k3_m4_rproc_da_to_va,
>> +	.get_loaded_rsc_table = k3_m4_get_loaded_rsc_table,
>> +};
>> +
>> +static int k3_m4_rproc_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct device_node *np = dev->of_node;
>> +	const struct k3_m4_rproc_dev_data *data;
>> +	struct k3_m4_rproc *kproc;
>> +	struct rproc *rproc;
>> +	const char *fw_name;
>> +	bool r_state = false;
>> +	bool p_state = false;
>> +	int ret = 0;
>> +
>> +	data = device_get_match_data(dev);
>> +	if (!data)
>> +		return -ENODEV;
>> +
>> +	ret = rproc_of_parse_firmware(dev, 0, &fw_name);
>> +	if (ret)
>> +		return dev_err_probe(dev, ret, "failed to parse firmware-name property\n");
>> +
>> +	rproc = devm_rproc_alloc(dev, dev_name(dev), &k3_m4_rproc_ops, fw_name,
>> +				 sizeof(*kproc));
>> +	if (!rproc)
>> +		return -ENOMEM;
>> +
>> +	rproc->has_iommu = false;
>> +	rproc->recovery_disabled = true;
>> +	if (data->uses_lreset) {
>> +		rproc->ops->prepare = k3_m4_rproc_prepare;
>> +		rproc->ops->unprepare = k3_m4_rproc_unprepare;
>> +	}
>> +	kproc = rproc->priv;
>> +	kproc->rproc = rproc;
>> +	kproc->dev = dev;
>> +	kproc->data = data;
>> +
>> +	kproc->ti_sci = devm_ti_sci_get_by_phandle(dev, "ti,sci");
>> +	if (IS_ERR(kproc->ti_sci))
>> +		return dev_err_probe(dev, PTR_ERR(kproc->ti_sci),
>> +				     "failed to get ti-sci handle\n");
>> +
>> +	ret = of_property_read_u32(np, "ti,sci-dev-id", &kproc->ti_sci_id);
>> +	if (ret)
>> +		return dev_err_probe(dev, ret, "missing 'ti,sci-dev-id' property\n");
>> +
>> +	kproc->reset = devm_reset_control_get_exclusive(dev, NULL);
>> +	if (IS_ERR(kproc->reset))
>> +		return dev_err_probe(dev, PTR_ERR(kproc->reset), "failed to get reset\n");
> 
> What happens when devm_reset_control_get_exclusive() returns NULL?
> 

Only the _optional_ version of this fuction can return NULL, this fuction
will always return an error if the reset cannot be taken.

>> +
>> +	kproc->tsp = k3_m4_rproc_of_get_tsp(dev, kproc->ti_sci);
>> +	if (IS_ERR(kproc->tsp))
>> +		return dev_err_probe(dev, PTR_ERR(kproc->tsp),
>> +				     "failed to construct ti-sci proc control\n");
>> +
>> +	ret = ti_sci_proc_request(kproc->tsp);
>> +	if (ret < 0)
>> +		return dev_err_probe(dev, ret, "ti_sci_proc_request failed\n");
>> +	ret = devm_add_action_or_reset(dev, k3_m4_release_tsp, kproc->tsp);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = k3_m4_rproc_of_get_memories(pdev, kproc);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = k3_m4_reserved_mem_init(kproc);
>> +	if (ret)
>> +		return dev_err_probe(dev, ret, "reserved memory init failed\n");
>> +
>> +	ret = kproc->ti_sci->ops.dev_ops.is_on(kproc->ti_sci, kproc->ti_sci_id,
>> +					       &r_state, &p_state);
>> +	if (ret)
>> +		return dev_err_probe(dev, ret,
>> +				     "failed to get initial state, mode cannot be determined\n");
>> +
>> +	/* configure devices for either remoteproc or IPC-only mode */
>> +	if (p_state) {
>> +		dev_info(dev, "configured M4 for IPC-only mode\n");
>> +		rproc->state = RPROC_DETACHED;
>> +		/* override rproc ops with only required IPC-only mode ops */
>> +		rproc->ops->prepare = NULL;
>> +		rproc->ops->unprepare = NULL;
>> +		rproc->ops->start = NULL;
>> +		rproc->ops->stop = NULL;
>> +		rproc->ops->attach = k3_m4_rproc_attach;
>> +		rproc->ops->detach = k3_m4_rproc_detach;
>> +		rproc->ops->get_loaded_rsc_table = k3_m4_get_loaded_rsc_table;
> 
> Why are the last 3 assignment needed when they are already set in the
> declaration of k3_m4_rproc_ops?
> 

Good point, seems none of these overrides should be needed, start()/stop()
are not called for ATTCHED/DETACHED cores anyway, opposite is true for attach()/detach().

I'll drop these overrides.

>> +	} else {
>> +		dev_info(dev, "configured M4 for remoteproc mode\n");
>> +		/*
>> +		 * ensure the M4 local reset is asserted to ensure the core
>> +		 * doesn't execute bogus code in .prepare() when the module
>> +		 * reset is released.
>> +		 */
>> +		if (data->uses_lreset) {
>> +			ret = reset_control_status(kproc->reset);
>> +			if (ret < 0) {
>> +				return dev_err_probe(dev, ret, "failed to get reset status\n");
>> +			} else if (ret == 0) {
>> +				dev_warn(dev, "local reset is deasserted for device\n");
>> +				k3_m4_rproc_reset(kproc);
>> +			}
>> +		}
>> +	}
>> +
>> +	ret = devm_rproc_add(dev, rproc);
>> +	if (ret)
>> +		return dev_err_probe(dev, ret,
>> +				     "failed to add register device with remoteproc core\n");
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct k3_m4_rproc_mem_data am64_m4_mems[] = {
>> +	{ .name = "iram", .dev_addr = 0x0 },
>> +	{ .name = "dram", .dev_addr = 0x30000 },
>> +};
> 
> Is this hardcoded in the hardware and never expected to change?  If not please
> add to the DT bindings.
> 

This is a hardware hardcoded address and will be the same for this class
of K3 M4 cores.

Thanks,
Andrew

> More comments later or tomorrow.
> 
> Thanks,
> Mathieu
> 
>> +
>> +static const struct k3_m4_rproc_dev_data am64_m4_data = {
>> +	.mems = am64_m4_mems,
>> +	.num_mems = ARRAY_SIZE(am64_m4_mems),
>> +	.uses_lreset = true,
>> +};
>> +
>> +static const struct of_device_id k3_m4_of_match[] = {
>> +	{ .compatible = "ti,am64-m4fss", .data = &am64_m4_data, },
>> +	{ /* sentinel */ },
>> +};
>> +MODULE_DEVICE_TABLE(of, k3_m4_of_match);
>> +
>> +static struct platform_driver k3_m4_rproc_driver = {
>> +	.probe	= k3_m4_rproc_probe,
>> +	.driver	= {
>> +		.name = "k3-m4-rproc",
>> +		.of_match_table = k3_m4_of_match,
>> +	},
>> +};
>> +module_platform_driver(k3_m4_rproc_driver);
>> +
>> +MODULE_AUTHOR("Hari Nagalla <hnagalla@ti.com>");
>> +MODULE_DESCRIPTION("TI K3 M4 Remoteproc driver");
>> +MODULE_LICENSE("GPL");
>> -- 
>> 2.39.2
>>