Re: [PATCH v8 5/5] remoteproc: Add initial zynqmp R5 remoteproc driver

[Stefano Stabellini]

On Mon, 10 Aug 2020, Ben Levinsky wrote:
> R5 is included in Xilinx Zynq UltraScale MPSoC so by adding this
> remotproc driver, we can boot the R5 sub-system in different
> configurations.

Which different configurations? How can you boot them?


> Signed-off-by: Ben Levinsky <ben.levinsky@xxxxxxxxxx>
> Signed-off-by: Wendy Liang <wendy.liang@xxxxxxxxxx>
> Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx>
> Signed-off-by: Ed Mooring <ed.mooring@xxxxxxxxxx>
> Signed-off-by: Jason Wu <j.wu@xxxxxxxxxx>
> ---
>  v2:
>  - remove domain struct as per review from Mathieu
>  v3:
>  - add xilinx-related platform mgmt fn's instead of wrapping around
>    function pointer in xilinx eemi ops struct
>  v4:
>  - add default values for enums
>  - fix formatting as per checkpatch.pl --strict. Note that 1 warning and 1 check
>    are still raised as each is due to fixing the warning results in that
>  particular line going over 80 characters.
>  v5:
>  - parse_fw change from use of rproc_of_resm_mem_entry_init to
>  rproc_mem_entry_init and use of alloc/release
>  - var's of type zynqmp_r5_pdata all have same local variable name
>  - use dev_dbg instead of dev_info
>  v6:
>  - adding memory carveouts is handled much more similarly. All mem
>  carveouts are
>    now described in reserved memory as needed. That is, TCM nodes are not
>    coupled to remoteproc anymore. This is reflected in the remoteproc R5
>  driver
>    and the device tree binding.
>  - remove mailbox from device tree binding as it is not necessary for elf
>    loading
>  - use lockstep-mode property for configuring RPU
>  v7:
>  - remove unused headers
>  - change  u32 *lockstep_mode ->  u32 lockstep_mode;
>  - change device-tree binding "lockstep-mode"  to xlnx,cluster-mode
>  - remove zynqmp_r5_mem_probe and loop to Probe R5 memory devices at
>    remoteproc-probe time
>  - remove is_r5_mode_set from  zynqmp rpu remote processor private data
>  - do not error out if no mailbox is provided
>  - remove zynqmp_r5_remoteproc_probe call of platform_set_drvdata as
>  pdata is
>    handled in zynqmp_r5_remoteproc_remove
> v8:
>  - remove old acks, reviewed-by's in commit message
> ---
>  drivers/remoteproc/Kconfig                |  10 +
>  drivers/remoteproc/Makefile               |   1 +
>  drivers/remoteproc/zynqmp_r5_remoteproc.c | 911 ++++++++++++++++++++++
>  3 files changed, 922 insertions(+)
>  create mode 100644 drivers/remoteproc/zynqmp_r5_remoteproc.c
> 
> diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
> index c4d1731295eb..342a7e668636 100644
> --- a/drivers/remoteproc/Kconfig
> +++ b/drivers/remoteproc/Kconfig
> @@ -249,6 +249,16 @@ config STM32_RPROC
>  
>  	  This can be either built-in or a loadable module.
>  
> +config ZYNQMP_R5_REMOTEPROC
> +	tristate "ZynqMP_R5 remoteproc support"
> +	depends on ARM64 && PM && ARCH_ZYNQMP
> +	select RPMSG_VIRTIO
> +	select MAILBOX
> +	select ZYNQMP_IPI_MBOX
> +	help
> +	  Say y here to support ZynqMP R5 remote processors via the remote
> +	  processor framework.
> +
>  endif # REMOTEPROC
>  
>  endmenu
> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
> index e8b886e511f0..04d1c95d06d7 100644
> --- a/drivers/remoteproc/Makefile
> +++ b/drivers/remoteproc/Makefile
> @@ -28,5 +28,6 @@ obj-$(CONFIG_QCOM_WCNSS_PIL)		+= qcom_wcnss_pil.o
>  qcom_wcnss_pil-y			+= qcom_wcnss.o
>  qcom_wcnss_pil-y			+= qcom_wcnss_iris.o
>  obj-$(CONFIG_ST_REMOTEPROC)		+= st_remoteproc.o
> +obj-$(CONFIG_ZYNQMP_R5_REMOTEPROC)	+= zynqmp_r5_remoteproc.o
>  obj-$(CONFIG_ST_SLIM_REMOTEPROC)	+= st_slim_rproc.o
>  obj-$(CONFIG_STM32_RPROC)		+= stm32_rproc.o
> diff --git a/drivers/remoteproc/zynqmp_r5_remoteproc.c b/drivers/remoteproc/zynqmp_r5_remoteproc.c
> new file mode 100644
> index 000000000000..b600759e257e
> --- /dev/null
> +++ b/drivers/remoteproc/zynqmp_r5_remoteproc.c

I tried to build this but I get 4 warnings:

drivers/remoteproc/zynqmp_r5_remoteproc.c: In function 'handle_tcm_parsing':
drivers/remoteproc/zynqmp_r5_remoteproc.c:286:10: warning: return makes pointer from integer without a cast [-Wint-conversion]
   return -EINVAL;
          ^
drivers/remoteproc/zynqmp_r5_remoteproc.c:293:10: warning: return makes pointer from integer without a cast [-Wint-conversion]
   return -EINVAL;
          ^
drivers/remoteproc/zynqmp_r5_remoteproc.c:298:10: warning: return makes pointer from integer without a cast [-Wint-conversion]
   return -ENOMEM;
          ^
drivers/remoteproc/zynqmp_r5_remoteproc.c:317:10: warning: return makes pointer from integer without a cast [-Wint-conversion]
   return -ENOMEM;


Please fix all warnings before submitting to the list.


> @@ -0,0 +1,911 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Zynq R5 Remote Processor driver
> + *
> + * Copyright (C) 2019, 2020 Xilinx Inc. Ben Levinsky <ben.levinsky@xxxxxxxxxx>
> + * Copyright (C) 2015 - 2018 Xilinx Inc.
> + * Copyright (C) 2015 Jason Wu <j.wu@xxxxxxxxxx>
> + *
> + * Based on origin OMAP and Zynq Remote Processor driver
> + *
> + * Copyright (C) 2012 Michal Simek <monstr@xxxxxxxxx>
> + * Copyright (C) 2012 PetaLogix
> + * Copyright (C) 2011 Texas Instruments, Inc.
> + * Copyright (C) 2011 Google, Inc.

In my opinion 8 copyright lines are too many. As you probably know, they
aren't actually necessary or useful (the SPDX line and git log are the
only things that matter). I would remove them all.


> + */
> +
> +#include <linux/atomic.h>

I just looked at the first #include and noticed that it is not actually
used. Please make sure that all headers included are necessary. (You can
try to remove them one by one to test if necessary.)


> +#include <linux/cpu.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/firmware/xlnx-zynqmp.h>
> +#include <linux/genalloc.h>
> +#include <linux/idr.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/list.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_irq.h>
> +#include <linux/of_platform.h>
> +#include <linux/of_reserved_mem.h>
> +#include <linux/pfn.h>
> +#include <linux/platform_device.h>
> +#include <linux/remoteproc.h>
> +#include <linux/skbuff.h>
> +#include <linux/slab.h>
> +#include <linux/sysfs.h>
> +
> +#include "remoteproc_internal.h"
> +
> +#define MAX_RPROCS	2 /* Support up to 2 RPU */
> +#define MAX_MEM_PNODES	4 /* Max power nodes for one RPU memory instance */
> +
> +#define DEFAULT_FIRMWARE_NAME	"rproc-rpu-fw"
> +
> +/* PM proc states */
> +#define PM_PROC_STATE_ACTIVE 1U
> +
> +/* IPI buffer MAX length */
> +#define IPI_BUF_LEN_MAX	32U
> +/* RX mailbox client buffer max length */
> +#define RX_MBOX_CLIENT_BUF_MAX	(IPI_BUF_LEN_MAX + \
> +				 sizeof(struct zynqmp_ipi_message))
> +
> +#define ZYNQMP_R5_NUM_TCM_BANKS 4
> +
> +/* lookup table mapping power-node-ID of TCM bank to absolute base address */
> +static unsigned long tcm_addr_to_pnode[ZYNQMP_R5_NUM_TCM_BANKS][2] = {
> +	{0xFFE00000,	0xF },
> +	{0xFFE20000,	0x10},
> +	{0xFFE90000,	0x10},
> +	{0xFFEB0000,	0x11},
> +};
> +
> +static bool autoboot __read_mostly;

Please add a description of this parameter. What does it do? Why would
anybody enable it?


> +/**
> + * struct zynqmp_r5_mem - zynqmp rpu memory data
> + * @pnode_id: TCM power domain ids
> + * @res: memory resource
> + * @node: list node
> + */
> +struct zynqmp_r5_mem {
> +	u32 pnode_id[MAX_MEM_PNODES];
> +	struct resource res;
> +	struct list_head node;
> +};
> +
> +/**
> + * struct zynqmp_r5_pdata - zynqmp rpu remote processor private data
> + * @dev: device of RPU instance
> + * @rproc: rproc handle
> + * @pnode_id: RPU CPU power domain id
> + * @mems: memory resources
> + * @is_r5_mode_set: indicate if r5 operation mode is set
> + * @tx_mc: tx mailbox client
> + * @rx_mc: rx mailbox client
> + * @tx_chan: tx mailbox channel
> + * @rx_chan: rx mailbox channel
> + * @mbox_work: mbox_work for the RPU remoteproc
> + * @tx_mc_skbs: socket buffers for tx mailbox client
> + * @rx_mc_buf: rx mailbox client buffer to save the rx message
> + */
> +struct zynqmp_r5_pdata {
> +	struct device dev;
> +	struct rproc *rproc;
> +	u32 pnode_id;
> +	struct list_head mems;
> +	bool is_r5_mode_set;
> +	struct mbox_client tx_mc;
> +	struct mbox_client rx_mc;
> +	struct mbox_chan *tx_chan;
> +	struct mbox_chan *rx_chan;
> +	struct work_struct mbox_work;
> +	struct sk_buff_head tx_mc_skbs;
> +	unsigned char rx_mc_buf[RX_MBOX_CLIENT_BUF_MAX];

A simple small reordering of the struct fields would lead to small
memory savings due to alignment.


> +};
> +
> +/**
> + * table of RPUs
> + */
> +struct zynqmp_r5_pdata rpus[MAX_RPROCS];
> +/**
> + *  RPU core configuration
     ^ spurious white space


> + */
> +enum rpu_oper_mode rpu_mode;
> +
> +/*
> + * r5_set_mode - set RPU operation mode
> + * @pdata: Remote processor private data
> + *
> + * set RPU oepration mode
> + *
> + * Return: 0 for success, negative value for failure
> + */
> +static int r5_set_mode(struct zynqmp_r5_pdata *pdata)
> +{
> +	u32 val[PAYLOAD_ARG_CNT] = {0}, expect, tcm_mode;
> +	struct device *dev = &pdata->dev;
> +	int ret;
> +
> +	expect = (u32)rpu_mode;
> +	ret = zynqmp_pm_get_rpu_mode(pdata->pnode_id, 0, 0, val);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to get RPU oper mode.\n");
> +		return ret;
> +	}
> +	if (val[0] == expect) {
> +		dev_dbg(dev, "RPU mode matches: %x\n", val[0]);
> +	} else {
> +		ret = zynqmp_pm_set_rpu_mode(pdata->pnode_id,
> +					     expect, 0, val);

It looks like zynqmp_pm_set_rpu_mode is actually ignoring the second
argument, so expect is not correctly handled?


> +		if (ret < 0) {
> +			dev_err(dev,
> +				"failed to set RPU oper mode.\n");
> +			return ret;
> +		}
> +	}
> +
> +	tcm_mode = (expect == (u32)PM_RPU_MODE_LOCKSTEP) ?
> +		    PM_RPU_TCM_COMB : PM_RPU_TCM_SPLIT;
> +	ret = zynqmp_pm_set_tcm_config(pdata->pnode_id, tcm_mode, 0, val);

Similarly, it looks like the second argument to zynqmp_pm_set_tcm_config
is actually ignored by the implementation of the function. So tcm_mode
here is not correctly handled by zynqmp_pm_set_tcm_config.

Also val has not been zeroed from the previous call.


> +	if (ret < 0) {
> +		dev_err(dev, "failed to config TCM to %x.\n",
> +			expect);
> +		return ret;
> +	}
> +	pdata->is_r5_mode_set = true;
> +	return 0;
> +}
> +
> +/*
> + * ZynqMP R5 remoteproc memory release function
> + */
> +static int zynqmp_r5_mem_release(struct rproc *rproc,
> +				 struct rproc_mem_entry *mem)
> +{
> +	struct zynqmp_r5_mem *priv;
> +	int i, ret;
> +	struct device *dev = &rproc->dev;
> +
> +	priv = mem->priv;
> +	if (!priv)
> +		return 0;
> +	for (i = 0; i < MAX_MEM_PNODES; i++) {
> +		if (priv->pnode_id[i]) {
> +			dev_dbg(dev, "%s, pnode %d\n",
> +				__func__, priv->pnode_id[i]);
> +			ret = zynqmp_pm_release_node(priv->pnode_id[i]);
> +			if (ret < 0) {
> +				dev_err(dev,
> +					"failed to release power node: %u\n",
> +					priv->pnode_id[i]);
> +				return ret;
> +			}
> +		} else {
> +			break;
> +		}
> +	}
> +	return 0;
> +}
> +
> +/*
> + * ZynqMP R5 remoteproc operations
> + */
> +static int zynqmp_r5_rproc_start(struct rproc *rproc)
> +{
> +	struct device *dev = rproc->dev.parent;
> +	struct zynqmp_r5_pdata *pdata = rproc->priv;
> +	enum rpu_boot_mem bootmem;
> +	int ret;
> +
> +	if ((rproc->bootaddr & 0xF0000000) == 0xF0000000)
> +		bootmem = PM_RPU_BOOTMEM_HIVEC;
> +	else
> +		bootmem = PM_RPU_BOOTMEM_LOVEC;
> +	dev_dbg(dev, "RPU boot from %s.",
> +		bootmem == PM_RPU_BOOTMEM_HIVEC ? "OCM" : "TCM");
> +	ret = zynqmp_pm_request_wakeup(pdata->pnode_id, 1,
> +				       bootmem, ZYNQMP_PM_REQUEST_ACK_NO);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to boot R5.\n");
> +		return ret;
> +	}
> +	return 0;
> +}
> +
> +static int zynqmp_r5_rproc_stop(struct rproc *rproc)
> +{
> +	struct zynqmp_r5_pdata *pdata = rproc->priv;
> +	int ret;
> +
> +	ret = zynqmp_pm_force_powerdown(pdata->pnode_id,
> +					ZYNQMP_PM_REQUEST_ACK_BLOCKING);
> +	if (ret < 0) {
> +		dev_err(&pdata->dev, "failed to shutdown R5.\n");
> +		return ret;
> +	}
> +	return 0;
> +}
> +
> +static int zynqmp_r5_rproc_mem_alloc(struct rproc *rproc,
> +				      struct rproc_mem_entry *mem)
> +{
> +	struct device *dev = rproc->dev.parent;
> +	void *va;
> +
> +	dev_dbg(rproc->dev.parent, "map memory: %pa\n", &mem->dma);
> +	va = ioremap_wc(mem->dma, mem->len);
> +	if (IS_ERR_OR_NULL(va)) {
> +		dev_err(dev, "Unable to map memory region: %pa+%lx\n",
> +			&mem->dma, mem->len);
> +		return -ENOMEM;
> +	}
> +
> +	/* Update memory entry va */
> +	mem->va = va;
> +	return 0;
> +}
> +
> +static int zynqmp_r5_rproc_mem_release(struct rproc *rproc,
> +				       struct rproc_mem_entry *mem)
> +{
> +	dev_dbg(rproc->dev.parent, "unmap memory: %pa\n", &mem->dma);
> +	iounmap(mem->va);
> +
> +	return 0;
> +}
> +
> +/*
> + * TCM needs mapping to R5 relative address and xilinx platform mgmt call
> + */
> +struct rproc_mem_entry *handle_tcm_parsing(struct device *dev,
> +					    struct reserved_mem *rmem,
> +					    struct device_node *node,
> +					    int lookup_idx)
> +{
> +	void *va;
> +	dma_addr_t dma;
> +	resource_size_t size;
> +	int ret;
> +	u32 pnode_id;
> +	struct resource rsc;
> +	struct rproc_mem_entry *mem;
> +
> +	pnode_id =  tcm_addr_to_pnode[lookup_idx][1];
> +	ret = zynqmp_pm_request_node(pnode_id,
> +				     ZYNQMP_PM_CAPABILITY_ACCESS, 0,
> +				     ZYNQMP_PM_REQUEST_ACK_BLOCKING);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to request power node: %u\n", pnode_id);
> +		return -EINVAL;
> +	}
> +
> +	ret = of_address_to_resource(node, 0, &rsc);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to get resource of memory %s",
> +			of_node_full_name(node));
> +		return -EINVAL;
> +	}
> +	size = resource_size(&rsc);
> +	va = devm_ioremap_wc(dev, rsc.start, size);
> +	if (!va)
> +		return -ENOMEM;
> +
> +	/* zero out tcm base address */
> +	if (rsc.start & 0xffe00000) {
> +		/* R5 can't see anything past 0xfffff so wipe it */
> +		rsc.start &= 0x000fffff;

If that is the case why not do:

  rsc.start &= 0x000fffff;

unconditionally? if (rsc.start & 0xffe00000) is superfluous. 

But I thought that actually the R5s could see TCM at both the low
address (< 0x000fffff) and also at the high address (i.e. 0xffe00000).


> +		/*
> +		 * handle tcm banks 1 a and b (0xffe9000 and
> +		 * 0xffeb0000)
> +		 */
> +		if (rsc.start & 0x80000)
> +			rsc.start -= 0x90000;

It is very unclear to me why we have to do this


> +	}
> +
> +	dma = (dma_addr_t)rsc.start;

Given the way the dma parameter is used by
rproc_alloc_registered_carveouts, I think it might be best to pass the
original start address (i.e. 0xffe00000) as dma.


> +	mem = rproc_mem_entry_init(dev, va, dma, (int)size, rsc.start,
> +				   NULL, zynqmp_r5_mem_release,

I don't know too much about the remoteproc APIs, but shouldn't you be
passing zynqmp_r5_rproc_mem_alloc to it instead of NULL?


> +				   rsc.name);
> +	if (!mem)
> +		return -ENOMEM;
> +
> +	return mem;
> +}
> +
> +static int parse_mem_regions(struct rproc *rproc)
> +{
> +	int num_mems, i;
> +	struct zynqmp_r5_pdata *pdata = rproc->priv;
> +	struct device *dev =  &pdata->dev;
> +	struct device_node *np = dev->of_node;
> +	struct rproc_mem_entry *mem;
> +
> +	num_mems = of_count_phandle_with_args(np, "memory-region", NULL);
> +	if (num_mems <= 0)
> +		return 0;
> +	for (i = 0; i < num_mems; i++) {
> +		struct device_node *node;
> +		struct reserved_mem *rmem;
> +
> +		node = of_parse_phandle(np, "memory-region", i);

Check node != NULL ?


> +		rmem = of_reserved_mem_lookup(node);
> +		if (!rmem) {
> +			dev_err(dev, "unable to acquire memory-region\n");
> +			return -EINVAL;
> +		}
> +
> +		if (strstr(node->name, "vdev0buffer")) {

vdev0buffer is not described in the device tree bindings, is that
normal/expected?


> +			/* Register DMA region */
> +			mem = rproc_mem_entry_init(dev, NULL,
> +						   (dma_addr_t)rmem->base,
> +						   rmem->size, rmem->base,
> +						   NULL, NULL,
> +						   "vdev0buffer");
> +			if (!mem) {
> +				dev_err(dev, "unable to initialize memory-region %s\n",
> +					node->name);
> +				return -ENOMEM;
> +			}
> +			dev_dbg(dev, "parsed %s at  %llx\r\n", mem->name,
> +				mem->dma);
> +		} else if (strstr(node->name, "vdev0vring")) {

Same here


> +			int vring_id;
> +			char name[16];
> +
> +			/*
> +			 * can be 1 of multiple vring IDs per IPC channel
> +			 * e.g. 'vdev0vring0' and 'vdev0vring1'
> +			 */
> +			vring_id = node->name[14] - '0';

Where does the "14" comes from? Are we sure it is not possible to have a
node->name smaller than 14 chars?


> +			snprintf(name, sizeof(name), "vdev0vring%d", vring_id);
> +			/* Register vring */
> +			mem = rproc_mem_entry_init(dev, NULL,
> +						   (dma_addr_t)rmem->base,
> +						   rmem->size, rmem->base,
> +						   zynqmp_r5_rproc_mem_alloc,
> +						   zynqmp_r5_rproc_mem_release,
> +						   name);
> +			dev_dbg(dev, "parsed %s at %llx\r\n", mem->name,
> +				mem->dma);
> +		} else {
> +			int idx;
> +
> +			/*
> +			 * if TCM update address space for R5 and
> +			 * make xilinx platform mgmt call
> +			 */
> +			for (idx = 0; idx < ZYNQMP_R5_NUM_TCM_BANKS; idx++) {
> +				if (tcm_addr_to_pnode[idx][0] == rmem->base)
> +					break;

There is something I don't quite understand. If the memory region to use
is TCM, why would it be also described under reserved-memory?
Reserved-memory is for normal memory being reserved, while TCM is not
normal memory. Am I missing something?


> +			}
> +
> +			if (idx != ZYNQMP_R5_NUM_TCM_BANKS) {
> +				mem = handle_tcm_parsing(dev, rmem, node, idx);
> +			} else {
> +				mem = rproc_mem_entry_init(dev, NULL,
> +						   (dma_addr_t)rmem->base,
> +						   rmem->size, rmem->base,
> +						   zynqmp_r5_rproc_mem_alloc,
> +						   zynqmp_r5_rproc_mem_release,
> +						   node->name);

This case looks identical to the vdev0vring above. Is the difference
really just in the "name"? If so, can we merge the two cases into one?


> +			}
> +
> +			if (!mem) {
> +				dev_err(dev,
> +					"unable to init memory-region %s\n",
> +					node->name);
> +				return -ENOMEM;
> +			}
> +		}
> +		rproc_add_carveout(rproc, mem);
> +	}
> +
> +	return 0;
> +}
> +
> +static int zynqmp_r5_parse_fw(struct rproc *rproc, const struct firmware *fw)
> +{
> +	int ret;
> +	struct zynqmp_r5_pdata *pdata = rproc->priv;
> +	struct device *dev = &pdata->dev;
> +
> +	ret = parse_mem_regions(rproc);
> +	if (ret) {
> +		dev_err(dev, "parse_mem_regions failed %x\n", ret);
> +		return ret;
> +	}
> +
> +	ret = rproc_elf_load_rsc_table(rproc, fw);
> +	if (ret == -EINVAL) {
> +		dev_info(dev, "no resource table found.\n");
> +		ret = 0;

Why do we want to continue ignoring the error in this case?


> +	}
> +	return ret;
> +}
> +
> +/* kick a firmware */
> +static void zynqmp_r5_rproc_kick(struct rproc *rproc, int vqid)
> +{
> +	struct device *dev = rproc->dev.parent;
> +	struct zynqmp_r5_pdata *pdata = rproc->priv;
> +
> +	dev_dbg(dev, "KICK Firmware to start send messages vqid %d\n", vqid);
> +
> +	if (vqid < 0) {
> +		/* If vqid is negative, does not pass the vqid to
> +		 * mailbox. As vqid is supposed to be 0 or possive.
> +		 * It also gives a way to just kick instead but
> +		 * not use the IPI buffer. It is better to provide
> +		 * a proper way to pass the short message, which will
> +		 * need to sync to upstream first, for now,
> +		 * use negative vqid to assume no message will be
> +		 * passed with IPI buffer, but just raise interrupt.
> +		 * This will be faster as it doesn't need to copy the
> +		 * message to the IPI buffer.

I take that by "upstream" you mean the upstream Linux kernel community?
Did the conversation happen?


> +		 * It will ignore the return, as failure is due to
> +		 * there already kicks in the mailbox queue.
> +		 */
> +		(void)mbox_send_message(pdata->tx_chan, NULL);
> +	} else {
> +		struct sk_buff *skb;
> +		unsigned int skb_len;
> +		struct zynqmp_ipi_message *mb_msg;
> +		int ret;
> +
> +		skb_len = (unsigned int)(sizeof(vqid) + sizeof(mb_msg));
> +		skb = alloc_skb(skb_len, GFP_ATOMIC);
> +		if (!skb) {
> +			dev_err(dev,
> +				"Failed to allocate skb to kick remote.\n");
> +			return;
> +		}
> +		mb_msg = (struct zynqmp_ipi_message *)skb_put(skb, skb_len);
> +		mb_msg->len = sizeof(vqid);
> +		memcpy(mb_msg->data, &vqid, sizeof(vqid));
> +		skb_queue_tail(&pdata->tx_mc_skbs, skb);
> +		ret = mbox_send_message(pdata->tx_chan, mb_msg);
> +		if (ret < 0) {
> +			dev_warn(dev, "Failed to kick remote.\n");
> +			skb_dequeue_tail(&pdata->tx_mc_skbs);
> +			kfree_skb(skb);
> +		}
> +	}
> +}
> +
> +static struct rproc_ops zynqmp_r5_rproc_ops = {
> +	.start		= zynqmp_r5_rproc_start,
> +	.stop		= zynqmp_r5_rproc_stop,
> +	.load		= rproc_elf_load_segments,
> +	.parse_fw	= zynqmp_r5_parse_fw,
> +	.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,
> +};
> +
> +/* zynqmp_r5_mem_probe() - probes RPU TCM memory device
> + * @pdata: pointer to the RPU remoteproc private data
> + * @node: pointer to the memory node
> + *
> + * Function to retrieve resources for RPU TCM memory device.
> + */
> +static int zynqmp_r5_mem_probe(struct zynqmp_r5_pdata *pdata,
> +			       struct device_node *node)
> +{

TCM nodes as children of the zynqmp_r5_remoteproc node are not described
in device tree, hence, they should not be parsed here.


> +	struct device *dev;
> +	struct zynqmp_r5_mem *mem;
> +	int ret;
> +	struct property *prop;
> +	const __be32 *cur;
> +	u32 val;
> +	int i;
> +
> +	dev = &pdata->dev;
> +	mem = devm_kzalloc(dev, sizeof(*mem), GFP_KERNEL);
> +	if (!mem)
> +		return -ENOMEM;
> +	ret = of_address_to_resource(node, 0, &mem->res);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to get resource of memory %s",
> +			of_node_full_name(node));
> +		return -EINVAL;
> +	}
> +
> +	/* Get the power domain id */
> +	i = 0;
> +	if (of_find_property(node, "pnode-id", NULL)) {
> +		of_property_for_each_u32(node, "pnode-id", prop, cur, val)
> +			mem->pnode_id[i++] = val;
> +	}
> +	list_add_tail(&mem->node, &pdata->mems);
> +	return 0;
> +}
> +
> +/**
> + * zynqmp_r5_release() - ZynqMP R5 device release function
> + * @dev: pointer to the device struct of ZynqMP R5
> + *
> + * Function to release ZynqMP R5 device.
> + */
> +static void zynqmp_r5_release(struct device *dev)
> +{
> +	struct zynqmp_r5_pdata *pdata;
> +	struct rproc *rproc;
> +	struct sk_buff *skb;
> +
> +	pdata = dev_get_drvdata(dev);
> +	rproc = pdata->rproc;
> +	if (rproc) {
> +		rproc_del(rproc);
> +		rproc_free(rproc);
> +	}
> +	if (pdata->tx_chan)
> +		mbox_free_channel(pdata->tx_chan);
> +	if (pdata->rx_chan)
> +		mbox_free_channel(pdata->rx_chan);
> +	/* Discard all SKBs */
> +	while (!skb_queue_empty(&pdata->tx_mc_skbs)) {
> +		skb = skb_dequeue(&pdata->tx_mc_skbs);
> +		kfree_skb(skb);
> +	}
> +
> +	put_device(dev->parent);
> +}
> +
> +/**
> + * event_notified_idr_cb() - event notified idr callback
> + * @id: idr 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;
> +
> +	(void)rproc_vq_interrupt(rproc, id);
> +	return 0;
> +}
> +
> +/**
> + * handle_event_notified() - remoteproc notification work funciton
> + * @work: pointer to the work structure
> + *
> + * It checks each registered remoteproc notify IDs.
> + */
> +static void handle_event_notified(struct work_struct *work)
> +{
> +	struct rproc *rproc;
> +	struct zynqmp_r5_pdata *pdata;
> +
> +	pdata = container_of(work, struct zynqmp_r5_pdata, mbox_work);
> +
> +	(void)mbox_send_message(pdata->rx_chan, NULL);
> +	rproc = pdata->rproc;
> +	/*
> +	 * We only use IPI for interrupt. The firmware side may or may
> +	 * not write the notifyid when it trigger IPI.
> +	 * And thus, we scan through all the registered notifyids.
> +	 */
> +	idr_for_each(&rproc->notifyids, event_notified_idr_cb, rproc);

This looks expensive. Should we at least check whether the notifyid was
written as first thing before doing the scan?


> +}
> +
> +/**
> + * zynqmp_r5_mb_rx_cb() - Receive channel mailbox callback
> + * @cl: mailbox client
> + * @mssg: message pointer
> + *
> + * It will schedule the R5 notification work.
> + */
> +static void zynqmp_r5_mb_rx_cb(struct mbox_client *cl, void *mssg)
> +{
> +	struct zynqmp_r5_pdata *pdata;
> +
> +	pdata = container_of(cl, struct zynqmp_r5_pdata, rx_mc);
> +	if (mssg) {
> +		struct zynqmp_ipi_message *ipi_msg, *buf_msg;
> +		size_t len;
> +
> +		ipi_msg = (struct zynqmp_ipi_message *)mssg;
> +		buf_msg = (struct zynqmp_ipi_message *)pdata->rx_mc_buf;
> +		len = (ipi_msg->len >= IPI_BUF_LEN_MAX) ?
> +		      IPI_BUF_LEN_MAX : ipi_msg->len;
> +		buf_msg->len = len;
> +		memcpy(buf_msg->data, ipi_msg->data, len);
> +	}
> +	schedule_work(&pdata->mbox_work);
> +}
> +
> +/**
> + * zynqmp_r5_mb_tx_done() - Request has been sent to the remote
> + * @cl: mailbox client
> + * @mssg: pointer to the message which has been sent
> + * @r: status of last TX - OK or error
> + *
> + * It will be called by the mailbox framework when the last TX has done.
> + */
> +static void zynqmp_r5_mb_tx_done(struct mbox_client *cl, void *mssg, int r)
> +{
> +	struct zynqmp_r5_pdata *pdata;
> +	struct sk_buff *skb;
> +
> +	if (!mssg)
> +		return;
> +	pdata = container_of(cl, struct zynqmp_r5_pdata, tx_mc);
> +	skb = skb_dequeue(&pdata->tx_mc_skbs);
> +	kfree_skb(skb);
> +}
> +
> +/**
> + * zynqmp_r5_setup_mbox() - Setup mailboxes
> + *
> + * @pdata: pointer to the ZynqMP R5 processor platform data
> + * @node: pointer of the device node
> + *
> + * Function to setup mailboxes to talk to RPU.
> + *
> + * Return: 0 for success, negative value for failure.
> + */
> +static int zynqmp_r5_setup_mbox(struct zynqmp_r5_pdata *pdata,
> +				struct device_node *node)
> +{
> +	struct device *dev = &pdata->dev;
> +	struct mbox_client *mclient;
> +
> +	/* Setup TX mailbox channel client */
> +	mclient = &pdata->tx_mc;
> +	mclient->dev = dev;
> +	mclient->rx_callback = NULL;
> +	mclient->tx_block = false;
> +	mclient->knows_txdone = false;
> +	mclient->tx_done = zynqmp_r5_mb_tx_done;
> +
> +	/* Setup TX mailbox channel client */
> +	mclient = &pdata->rx_mc;
> +	mclient->dev = dev;
> +	mclient->rx_callback = zynqmp_r5_mb_rx_cb;
> +	mclient->tx_block = false;
> +	mclient->knows_txdone = false;
> +
> +	INIT_WORK(&pdata->mbox_work, handle_event_notified);
> +
> +	/* Request TX and RX channels */
> +	pdata->tx_chan = mbox_request_channel_byname(&pdata->tx_mc, "tx");
> +	if (IS_ERR(pdata->tx_chan)) {
> +		dev_err(dev, "failed to request mbox tx channel.\n");
> +		pdata->tx_chan = NULL;
> +		return -EINVAL;
> +	}
> +	pdata->rx_chan = mbox_request_channel_byname(&pdata->rx_mc, "rx");
> +	if (IS_ERR(pdata->rx_chan)) {
> +		dev_err(dev, "failed to request mbox rx channel.\n");
> +		pdata->rx_chan = NULL;
> +		return -EINVAL;
> +	}
> +	skb_queue_head_init(&pdata->tx_mc_skbs);
> +	return 0;
> +}
> +
> +/**
> + * zynqmp_r5_probe() - Probes ZynqMP R5 processor device node
> + * @pdata: pointer to the ZynqMP R5 processor platform data
> + * @pdev: parent RPU domain platform device
> + * @node: pointer of the device node
> + *
> + * Function to retrieve the information of the ZynqMP R5 device node.
> + *
> + * Return: 0 for success, negative value for failure.
> + */
> +static int zynqmp_r5_probe(struct zynqmp_r5_pdata *pdata,
> +			   struct platform_device *pdev,
> +			   struct device_node *node)
> +{
> +	struct device *dev = &pdata->dev;
> +	struct rproc *rproc;
> +	struct device_node *nc;
> +	int ret;
> +
> +	/* Create device for ZynqMP R5 device */
> +	dev->parent = &pdev->dev;
> +	dev->release = zynqmp_r5_release;
> +	dev->of_node = node;
> +	dev_set_name(dev, "%s", of_node_full_name(node));
> +	dev_set_drvdata(dev, pdata);
> +	ret = device_register(dev);
> +	if (ret) {
> +		dev_err(dev, "failed to register device.\n");
> +		return ret;
> +	}
> +	get_device(&pdev->dev);
> +
> +	/* Allocate remoteproc instance */
> +	rproc = rproc_alloc(dev, dev_name(dev), &zynqmp_r5_rproc_ops, NULL, 0);
> +	if (!rproc) {
> +		dev_err(dev, "rproc allocation failed.\n");
> +		ret = -ENOMEM;
> +		goto error;
> +	}
> +	rproc->auto_boot = autoboot;
> +	pdata->rproc = rproc;
> +	rproc->priv = pdata;
> +
> +	/*
> +	 * The device has not been spawned from a device tree, so
> +	 * arch_setup_dma_ops has not been called, thus leaving
> +	 * the device with dummy DMA ops.
> +	 * Fix this by inheriting the parent's DMA ops and mask.
> +	 */

This comment looks ominous. Is it still true even in Linux master,
after Christoph rework of the dma_ops? Probably not?


> +	rproc->dev.dma_mask = pdev->dev.dma_mask;
> +	set_dma_ops(&rproc->dev, get_dma_ops(&pdev->dev));
> +
> +	/* Probe R5 memory devices */
> +	INIT_LIST_HEAD(&pdata->mems);
> +	for_each_available_child_of_node(node, nc) {
> +		ret = zynqmp_r5_mem_probe(pdata, nc);
> +		if (ret) {
> +			dev_err(dev, "failed to probe memory %s.\n",
> +				of_node_full_name(nc));
> +			goto error;
> +		}
> +	}
> +
> +	/* Set up DMA mask */
> +	ret = dma_set_coherent_mask(dev, DMA_BIT_MASK(32));
> +	if (ret) {
> +		dev_warn(dev, "dma_set_coherent_mask failed: %d\n", ret);
> +		/* If DMA is not configured yet, try to configure it. */
> +		ret = of_dma_configure(dev, node, true);
> +		if (ret) {
> +			dev_err(dev, "failed to configure DMA.\n");
> +			goto error;
> +		}
> +	}

It looks like we are following a trial-and-error approach to setup dma
coherency. Can we do the right thing without having to try first?

Specifically, in which circumstances of_dma_configure() would need to be
called again here?


> +	/* Get R5 power domain node */
> +	ret = of_property_read_u32(node, "pnode-id", &pdata->pnode_id);
> +	if (ret) {
> +		dev_err(dev, "failed to get power node id.\n");
> +		goto error;
> +	}
> +
> +	/* TODO Check if R5 is running */
> +
> +	/* Set up R5 if not already setup */
> +	ret = pdata->is_r5_mode_set ? 0 : r5_set_mode(pdata);
> +	if (ret) {
> +		dev_err(dev, "failed to set R5 operation mode.\n");
> +		return ret;
> +	}

is_r5_mode_set is set by r5_set_mode(), which is only called here.
So it looks like this check is important in cases where
zynqmp_r5_probe() is called twice for the same R5 node. But I don't
think that is supposed to happen?


> +	if (!of_get_property(dev->of_node, "mboxes", NULL)) {
> +		dev_dbg(dev, "no mailboxes.\n");
> +		goto error;
> +	} else {
> +		ret = zynqmp_r5_setup_mbox(pdata, node);
> +		if (ret < 0)
> +			goto error;

Given that mboxes is actually required, I think you should update the
device tree example with it. Otherwise, if mboxes is not required, then
we shouldn't fail with an error here if it is absent.


> +	}
> +
> +	/* Add R5 remoteproc */
> +	ret = rproc_add(rproc);
> +	if (ret) {
> +		dev_err(dev, "rproc registration failed\n");
> +		goto error;
> +	}
> +	return 0;
> +error:
> +	if (pdata->rproc)
> +		rproc_free(pdata->rproc);
> +	pdata->rproc = NULL;
> +	device_unregister(dev);
> +	put_device(&pdev->dev);
> +	return ret;
> +}
> +
> +static int zynqmp_r5_remoteproc_probe(struct platform_device *pdev)
> +{
> +	int ret, i = 0;
> +	u32 *lockstep_mode;
> +	struct device *dev = &pdev->dev;
> +	struct device_node *nc;
> +	struct zynqmp_r5_pdata *pdata;
> +
> +	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
> +	lockstep_mode = devm_kzalloc(dev, sizeof(u32 *), GFP_KERNEL);

Any reasons why lockstep_mode couldn't just be a local variable then use
&lockstep_mode when you need a reference?


> +	if (!pdata || !lockstep_mode)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, pdata);
> +
> +	of_property_read_u32(dev->of_node, "lockstep-mode", lockstep_mode);
> +
> +	if (!(*lockstep_mode)) {
> +		rpu_mode = PM_RPU_MODE_SPLIT;
> +	} else if (*lockstep_mode == 1) {
> +		rpu_mode = PM_RPU_MODE_LOCKSTEP;
> +	} else {
> +		dev_err(dev,
> +			"Invalid lockstep-mode mode provided - %x %d\n",
> +			*lockstep_mode, rpu_mode);
> +		return -EINVAL;
> +	}
> +	dev_dbg(dev, "RPU configuration: %s\r\n",
> +		(*lockstep_mode) ? "lockstep" : "split");
> +
> +	for_each_available_child_of_node(dev->of_node, nc) {
> +		ret = zynqmp_r5_probe(&rpus[i], pdev, nc);
> +		if (ret) {
> +			dev_err(dev, "failed to probe rpu %s.\n",
> +				of_node_full_name(nc));
> +			return ret;
> +		}
> +		i++;
> +	}
> +
> +	return 0;
> +}
> +
> +static int zynqmp_r5_remoteproc_remove(struct platform_device *pdev)
> +{
> +	int i;
> +
> +	for (i = 0; i < MAX_RPROCS; i++) {
> +		struct zynqmp_r5_pdata *pdata = &rpus[i];
> +		struct rproc *rproc;
> +
> +		rproc = pdata->rproc;
> +		if (rproc) {
> +			rproc_del(rproc);
> +			rproc_free(rproc);
> +			pdata->rproc = NULL;
> +		}
> +		if (pdata->tx_chan) {
> +			mbox_free_channel(pdata->tx_chan);
> +			pdata->tx_chan = NULL;
> +		}
> +		if (pdata->rx_chan) {
> +			mbox_free_channel(pdata->rx_chan);
> +			pdata->rx_chan = NULL;
> +		}
> +
> +		device_unregister(&pdata->dev);
> +	}
> +
> +	return 0;
> +}
> +
> +/* Match table for OF platform binding */
> +static const struct of_device_id zynqmp_r5_remoteproc_match[] = {
> +	{ .compatible = "xlnx,zynqmp-r5-remoteproc-1.0", },
> +	{ /* end of list */ },
> +};
> +MODULE_DEVICE_TABLE(of, zynqmp_r5_remoteproc_match);
> +
> +static struct platform_driver zynqmp_r5_remoteproc_driver = {
> +	.probe = zynqmp_r5_remoteproc_probe,
> +	.remove = zynqmp_r5_remoteproc_remove,
> +	.driver = {
> +		.name = "zynqmp_r5_remoteproc",
> +		.of_match_table = zynqmp_r5_remoteproc_match,
> +	},
> +};
> +module_platform_driver(zynqmp_r5_remoteproc_driver);
> +
> +module_param_named(autoboot,  autoboot, bool, 0444);
> +MODULE_PARM_DESC(autoboot,
> +		 "enable | disable autoboot. (default: false)");
> +
> +MODULE_AUTHOR("Ben Levinsky <ben.levinsky@xxxxxxxxxx>");
> +MODULE_LICENSE("GPL v2");