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From:   Punit Agrawal <punit1.agrawal@toshiba.co.jp>
To:     Ben Levinsky <ben.levinsky@xilinx.com>
Cc:     stefanos@xilinx.com, michals@xilinx.com,
        devicetree@vger.kernel.org, emooring@xilinx.com,
        michael.auchter@ni.com, Wendy Liang <wendy.liang@xilinx.com>,
        mathieu.poirier@linaro.org, Ed Mooring <ed.mooring@xilinx.com>,
        linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org,
        jliang@xilinx.com, robh+dt@kernel.org, Jason Wu <j.wu@xilinx.com>,
        Michal Simek <michal.simek@xilinx.com>,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v13 5/5] remoteproc: Add initial zynqmp R5 remoteproc driver
References: <20200904143209.31235-1-ben.levinsky@xilinx.com>
        <20200904143209.31235-6-ben.levinsky@xilinx.com>
Date:   Thu, 10 Sep 2020 17:52:00 +0900
In-Reply-To: <20200904143209.31235-6-ben.levinsky@xilinx.com> (Ben Levinsky's
        message of "Fri, 4 Sep 2020 07:32:09 -0700")
Message-ID: <87h7s6nhe7.fsf@kokedama.swc.toshiba.co.jp>
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Sender: linux-kernel-owner@vger.kernel.org
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Hi Ben,

Thanks for fixing the commit ordering issue. Some additional comments
below.

Ben Levinsky <ben.levinsky@xilinx.com> writes:

> R5 is included in Xilinx Zynq UltraScale MPSoC so by adding this
> remotproc driver, we can boot the R5 sub-system in different 2
> configurations: split or lock-step.

Suggest following edit for clarity -

"A Cortex R5 is included in the Xilinx Zync UltraScale MPSoC. Adding a
remoteproc driver, it's possible to boot the R5 sub-system in two
different configurations -

    * split
    * lock-step
"
>
> The Xilinx R5 Remoteproc Driver boots the R5's via calls to the Xilinx
> Platform Management Unit that handles the R5 configuration, memory access
> and R5 lifecycle management. The interface to this manager is done in this
> driver via zynqmp_pm_* function calls.
>
> Signed-off-by: Wendy Liang <wendy.liang@xilinx.com>
> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
> Signed-off-by: Ed Mooring <ed.mooring@xilinx.com>
> Signed-off-by: Jason Wu <j.wu@xilinx.com>
> Signed-off-by: Ben Levinsky <ben.levinsky@xilinx.com>
> ---

The patch fails to apply on v5.9-rc3. What kernel are the patches based
on? Please rebase and test before sending another update.

[...]

>  drivers/remoteproc/Kconfig                |  10 +
>  drivers/remoteproc/Makefile               |   1 +
>  drivers/remoteproc/zynqmp_r5_remoteproc.c | 898 ++++++++++++++++++++++
>  3 files changed, 909 insertions(+)
>  create mode 100644 drivers/remoteproc/zynqmp_r5_remoteproc.c
>
> diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
> index c4d1731295eb..dd9ed45654e0 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

The ARM64 dependency seems superfluous. Please drop it.

> +	select RPMSG_VIRTIO
> +	select MAILBOX

ZYNQMP_IPI_MBOX below implies MAILBOX. I think it is safe to drop
MAILBOX as well.

> +	select ZYNQMP_IPI_MBOX
> +	help
> +	  Say y or m 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..4fc4098ae1ea
> --- /dev/null
> +++ b/drivers/remoteproc/zynqmp_r5_remoteproc.c
> @@ -0,0 +1,898 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Zynq R5 Remote Processor driver
> + *
> + * Based on origin OMAP and Zynq Remote Processor driver
> + *
> + */
> +
> +#include <linux/firmware/xlnx-zynqmp.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_platform.h>
> +#include <linux/of_reserved_mem.h>
> +#include <linux/platform_device.h>
> +#include <linux/remoteproc.h>
> +#include <linux/skbuff.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"

This define doesn't seem to be used in the driver. Please drop it.

> +#define BANK_LIST_PROP "meta-memory-regions"
> +
> +/* PM proc states */
> +#define PM_PROC_STATE_ACTIVE 1U

Same for this macro as well.

> +
> +/* 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))
> +
> +/**
> + * 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
> + * @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 {
> +	unsigned char rx_mc_buf[RX_MBOX_CLIENT_BUF_MAX];
> +	struct mbox_client tx_mc;
> +	struct mbox_client rx_mc;
> +	struct work_struct mbox_work;
> +	struct sk_buff_head tx_mc_skbs;
> +	struct device dev;
> +	struct rproc *rproc;
> +	struct mbox_chan *tx_chan;
> +	struct mbox_chan *rx_chan;
> +	u32 pnode_id;
> +	bool is_r5_mode_set;
> +};

The order of the elements in documentation and the structure does not
match. Please align the order between the two.

> +
> +/**
> + * table of RPUs
> + */
> +struct zynqmp_r5_pdata rpus[MAX_RPROCS];
> +/**
> + * RPU core configuration
> + */
> +enum rpu_oper_mode rpu_mode;

Both the above variables should be local to this compilation
unit. Please mark them as "static".

> +
> +/*
> + * 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)
> +{
> +	struct device *dev = &pdata->dev;
> +	enum rpu_tcm_comb cur_tcm_mode;
> +	enum rpu_oper_mode cur_rpu_mode;
> +	int ret;
> +
> +	cur_rpu_mode = rpu_mode;

cur_rpu_mode gets overwritten on the next line. Please drop the
initialisation.

> +	ret = zynqmp_pm_get_rpu_mode(pdata->pnode_id, &cur_rpu_mode);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to get RPU oper mode.\n");

Please drop the error print. If for some reason you find them useful
please at least convert it to a debug print. Same for the other error
messages in this function.

> +		return ret;
> +	}
> +	if (rpu_mode == cur_rpu_mode) {
> +		dev_dbg(dev, "RPU mode matches: %x\n", rpu_mode);

I am not sure what value the debug message adds. Please rewrite to only
deal with the else condition, i.e., rpu_mode != cur_rpu_mode

> +	} else {
> +		ret = zynqmp_pm_set_rpu_mode(pdata->pnode_id,
> +					     cur_rpu_mode);

Setting the rpu_mode that was just retrieved is a null op. Please think
about what logic you are trying to implement.

> +		if (ret < 0) {
> +			dev_err(dev,
> +				"failed to set RPU oper mode.\n");
> +			return ret;
> +		}
> +	}
> +
> +	cur_tcm_mode = (cur_rpu_mode == PM_RPU_MODE_LOCKSTEP) ?
> +		    PM_RPU_TCM_COMB : PM_RPU_TCM_SPLIT;
> +	ret = zynqmp_pm_set_tcm_config(pdata->pnode_id, cur_tcm_mode);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to config TCM to %x.\n",
> +			cur_rpu_mode);
> +		return ret;
> +	}
> +	pdata->is_r5_mode_set = true;
> +	return 0;
> +}
> +
> +/*
> + * ZynqMP R5 remoteproc memory release function
> + */
> +static int tcm_mem_release(struct rproc *rproc, struct rproc_mem_entry *mem)
> +{
> +	u32 pnode_id;
> +	int ret;
> +	struct device *dev = &rproc->dev;
> +
> +	pnode_id = *(u32 *)mem->priv;
> +
> +	if (pnode_id <= 0)
> +		dev_err(dev, "rproc_mem_entry has null priv field\n");

If this is an error condition, then is it safe to continue with the
below operations?

> +
> +	iounmap(mem->va);
> +
> +	ret = zynqmp_pm_release_node(pnode_id);
> +	if (ret < 0)
> +		dev_err(dev, "failed to release power node: %u\n", pnode_id);
> +
> +	return ret;
> +}
> +
> +/*
> + * 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_wake(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_pwrdwn(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;
> +}
> +
> +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);
> +		if (!node) {
> +			dev_err(dev, "no memory-region specified\n");
> +			return -EINVAL;
> +		}
> +
> +		rmem = of_reserved_mem_lookup(node);
> +		if (!rmem) {
> +			dev_err(dev, "unable to acquire memory-region\n");
> +			return -EINVAL;
> +		}
> +
> +		if (strstr(node->name, "vdev0vring")) {
> +			int vring_id;
> +			char name[16];
> +
> +			/*
> +			 * expecting form of "rpuXvdev0vringX as documented
> +			 * in xilinx remoteproc device tree binding
> +			 */
> +			if (strlen(node->name) < 14) {
> +				dev_err(dev, "%pOF is less than 14 chars",
> +					node);
> +				return -EINVAL;
> +			}
> +
> +			/*
> +			 * can be 1 of multiple vring IDs per IPC channel
> +			 * e.g. 'vdev0vring0' and 'vdev0vring1'
> +			 */
> +			vring_id = node->name[14] - '0';
> +			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\n", mem->name,
> +				mem->dma);
> +		} else {
> +			/* Register DMA region */
> +			int (*alloc)(struct rproc *r,
> +				     struct rproc_mem_entry *rme);
> +			int (*release)(struct rproc *r,
> +				       struct rproc_mem_entry *rme);
> +			char name[20];
> +
> +			if (strstr(node->name, "vdev0buffer")) {
> +				alloc = NULL;
> +				release = NULL;
> +				strcpy(name, "vdev0buffer");
> +			} else {
> +				alloc = zynqmp_r5_rproc_mem_alloc;
> +				release = zynqmp_r5_rproc_mem_release;
> +				strcpy(name, node->name);
> +			}
> +
> +			mem = rproc_mem_entry_init(dev, NULL,
> +						   (dma_addr_t)rmem->base,
> +						   rmem->size, rmem->base,
> +						   alloc, release, name);
> +			if (!mem) {
> +				dev_err(dev,
> +					"unable to init memory-region %pOF\n",
> +					node);
> +				return -ENOMEM;
> +			}
> +			dev_dbg(dev, "parsed %s at  %llx\n", mem->name,
> +				mem->dma);
> +		}
> +		rproc_add_carveout(rproc, mem);
> +	}
> +
> +	return 0;
> +}
> +
> +/* call Xilix Platform manager to request access to TCM bank */
> +static int zyqmp_r5_pm_request_tcm(struct device_node *tcm_node,
> +				   struct device *dev,
> +				   u32 *pnode_id)
> +{
> +	int ret;
> +
> +	ret = of_property_read_u32(tcm_node, "pnode-id", pnode_id);
> +	if (ret) {
> +		dev_err(dev, "Can't parse pnode-id property\n");
> +		return ret;
> +	}
> +
> +	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 ret;
> +	}
> +
> +	return 0;
> +}
> +
> +/* Given tcm bank entry,
> + * this callback will set device address for R5 running on TCM
> + * and also setup virtual address for tcm bank remoteproc carveout
> + */
> +static int tcm_mem_alloc(struct rproc *rproc,
> +			 struct rproc_mem_entry *mem)
> +{
> +	void *va;
> +	struct device *dev = rproc->dev.parent;
> +
> +	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;
> +
> +	va = devm_ioremap_wc(dev, mem->da, mem->len);
> +	if (!va)
> +		return -ENOMEM;
> +	/* As R5 is 32 bit, wipe out extra high bits */
> +	mem->da &= 0x000fffff;
> +	/*
> +	 * handle tcm banks 1 a and b (0xffe90000 and oxffeb0000)
> +	 * As both of these the only common bit found not in tcm bank0 a or b
> +	 * is at 0x80000 use this mask to suss it out
> +	 */
> +	if (mem->da & 0x80000)
> +		/*
> +		 * similar to wiping tcm banks 0a and 0b with just the
> +		 * mask of 0x000fffff will translate to device addr's
> +		 * at 0x0 and 0x20000, need to do more to further translate
> +		 * tcm banks 1a and 1b at 0xffe90000 and oxffeb0000
> +		 * respectively to 0x0 and 0x20000
> +		 */
> +		mem->da -= 0x90000;
> +
> +	return 0;
> +}
> +
> +/*
> + * Given R5 node in remoteproc instance,
> + * allocate remoteproc carveout for TCM memory
> + * needed for firmware to be loaded
> + */
> +static int parse_tcm_banks(struct rproc *rproc)
> +{
> +	int i, num_banks;
> +
> +	struct zynqmp_r5_pdata *pdata = rproc->priv;
> +	struct device *dev = &pdata->dev;
> +	struct device_node *r5_node = dev->of_node;
> +
> +	/* go through tcm banks for r5 node */
> +	num_banks = of_count_phandle_with_args(r5_node, BANK_LIST_PROP, NULL);
> +	if (num_banks <= 0) {
> +		dev_err(dev, "need to specify TCM banks\n");
> +		return -EINVAL;
> +	}
> +	for (i = 0; i < num_banks; i++) {
> +		struct resource rsc;
> +		resource_size_t size;
> +		struct device_node *dt_node;
> +		struct rproc_mem_entry *mem;
> +		int ret;
> +		/*
> +		 * use u32 as zynqmp_pm* functions use this type
> +		 *
> +		 * use ptr because it needs be used later on when releasing
> +		 * each tcm node in tcm_mem_release
> +		 */
> +		u32 *pnode_id_ptr;
> +
> +		dt_node = of_parse_phandle(r5_node, BANK_LIST_PROP, i);
> +		if (!dt_node) {
> +			dev_err(dev, "no tcm banks specified\n");
> +			return -EINVAL;
> +		}
> +
> +		if (of_device_is_available(dt_node)) {
> +			dev_dbg(dev, "%pOF is available\n", dt_node);
> +
> +			/* get address */
> +			ret = of_address_to_resource(dt_node, 0, &rsc);
> +			if (ret < 0) {
> +				dev_err(dev, "fail to get rsc mem %pOF",
> +					dt_node);
> +				return -EINVAL;
> +			}
> +
> +			pnode_id_ptr = devm_kzalloc(dev, sizeof(*pdata),
> +						    GFP_KERNEL);
> +			if (!pnode_id_ptr)
> +				return -ENOMEM;
> +
> +			/* request access */
> +			zyqmp_r5_pm_request_tcm(dt_node, dev, pnode_id_ptr);
> +
> +			/* add carveout */
> +			size = resource_size(&rsc);
> +			mem = rproc_mem_entry_init(dev, NULL, rsc.start,
> +						   (int)size, rsc.start,
> +						   tcm_mem_alloc,
> +						   tcm_mem_release,
> +						   rsc.name);
> +			if (!mem)
> +				return -ENOMEM;
> +			mem->priv = (void *)pnode_id_ptr;
> +
> +			rproc_add_carveout(rproc, mem);
> +		} else {
> +			dev_info(dev, "node %pOF is not available\n", dt_node);
> +		}
> +	}
> +
> +	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_tcm_banks(rproc);
> +	if (ret) {
> +		dev_err(dev, "parse_tcm_banks failed %x\n", ret);
> +		return ret;
> +	}
> +
> +	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) {
> +		/*
> +		 * resource table only required for IPC.
> +		 * if not present, this is not necessarily an error;
> +		 * for example, loading r5 hello world application
> +		 * so simply inform user and keep going.
> +		 */
> +		dev_info(dev, "no resource table found.\n");
> +		ret = 0;
> +	}
> +	return ret;
> +}
> +
> +/* kick a firmware */
> +static void zynqmp_r5_rproc_kick(struct rproc *rproc, int vqid)
> +{
> +	struct sk_buff *skb;
> +	unsigned int skb_len;
> +	struct zynqmp_ipi_message *mb_msg;
> +	int ret;
> +
> +	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);
> +
> +	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_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 if tx_mc_skbs is initialized */
> +	if (&pdata->tx_mc_skbs.prev) {
> +		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);
> +}
> +
> +/**
> + * 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;
> +	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, "%pOF", 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;
> +	}
> +	pdata->rproc = rproc;
> +	rproc->priv = pdata;
> +
> +	/* Set up DMA mask */
> +	ret = dma_set_coherent_mask(dev, DMA_BIT_MASK(32));
> +	if (ret) {
> +		dev_err(&pdev->dev, "dma_set_coherent_mask: %d\n", ret);
> +		return ret;
> +	}
> +
> +	/* 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 */

Please address TODOs before posting patches for review. If it has been
addressed, then do remember to drop them.

> +
> +	/*
> +	 * Set up R5 if not already setup
> +	 * This check is needed as there are cases where
> +	 * a user might repeatedly do modprobe
> +	 * and modprobe -r. In this case, upon a
> +	 * subsequent load, this check is needed.
> +	 */
> +	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;
> +	}
> +
> +	if (!of_get_property(dev->of_node, "mboxes", NULL)) {
> +		dev_dbg(dev, "no mailboxes.\n");
> +	} else {
> +		ret = zynqmp_r5_setup_mbox(pdata, node);
> +		if (ret < 0)
> +			goto error;
> +	}
> +
> +	/* 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);
> +	if (!pdata)
> +		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 %x in %pOF\n",
> +			lockstep_mode, dev->of_node);
> +		return -EINVAL;
> +	}
> +	dev_dbg(dev, "RPU configuration: %s\n",
> +		lockstep_mode ? "lockstep" : "split");
> +
> +	for_each_available_child_of_node(dev->of_node, nc) {
> +		ret = zynqmp_r5_probe(&rpus[i], pdev, nc);

It feels a little dangerous to dereference rpu[i] without first checking
if i is valid - in case there are more child nodes than supported by the
driver.

There are quite a few issues with this driver, e.g., excessive error
prints, only debug statements in if condition branches - some stylistic
but many seem to be logic errors resulting from either lack of clarity
regarding how the kernel interacts with the hardware or lack of
sufficient testing.

I have tried to highlight some of the issues I noticed. Please address
these and review the driver carefully before posting the next update.

Thanks,
Punit

> +		if (ret) {
> +			dev_err(dev, "failed to probe rpu %pOF.\n", 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;
> +
> +		/* only do clean up for pdata with active rpu */
> +		if (pdata->pnode_id == 0)
> +			continue;
> +
> +		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;
> +		}
> +		if (&(&pdata->dev)->dma_pools)
> +			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_AUTHOR("Ben Levinsky <ben.levinsky@xilinx.com>");
> +MODULE_LICENSE("GPL v2");