Re: [PATCH v2 2/4] remoteproc: k3-r5: Add a remoteproc driver for R5F subsystem

Mathieu Poirier
2020-07-09T18:11:07Z

Good day Suman,

On Mon, Jun 29, 2020 at 09:49:20PM -0500, Suman Anna wrote:
> The TI K3 family of SoCs typically have one or more dual-core Arm Cortex
> R5F processor clusters/subsystems (R5FSS). This R5F subsystem/cluster
> can be configured at boot time to be either run in a LockStep mode or in
> an Asymmetric Multi Processing (AMP) fashion in Split-mode. This subsystem
> has 64 KB each Tightly-Coupled Memory (TCM) internal memories for each
> core split between two banks - TCMA and TCMB (further interleaved into
> two banks). The subsystem does not have an MMU, but has a Region Address
> Translater (RAT) module that is accessible only from the R5Fs for providing
> translations between 32-bit CPU addresses into larger system bus addresses.
>
> Add a remoteproc driver to support this subsystem to be able to load and
> boot the R5F cores primarily in LockStep mode. The code also includes the
> base support for Split mode. Error Recovery and Power Management features
> are not currently supported. Loading support includes the internal TCMs
> and DDR. RAT support is left for a future patch, and as such the reserved
> memory carveout regions are all expected to be using memory regions within
> the first 2 GB.
>
> The R5F remote processors do not have an MMU, and so require fixed memory
> carveout regions matching the firmware image addresses. Support for this
> is provided by mandating multiple memory regions to be attached to the
> remoteproc device. The first memory region will be used to serve as the
> DMA pool for all dynamic allocations like the vrings and vring buffers.
> The remaining memory regions are mapped into the kernel at device probe
> time, and are used to provide address translations for firmware image
> segments without the need for any RSC_CARVEOUT entries. Any firmware
> image using memory outside of the supplied reserved memory carveout
> regions will be errored out.
>
> The R5F processors on TI K3 SoCs require a specific sequence for booting
> and shutting down the processors. This sequence is also dependent on the
> mode (LockStep or Split) the R5F cluster is configured for. The R5F cores
> have a Memory Protection Unit (MPU) that has a default configuration that
> does not allow the cores to run out of DDR out of reset. This is resolved
> by using the TCMs for boot-strapping code that applies the appropriate
> executable permissions on desired DDR memory. The loading into the TCMs
> requires that the resets be released first with the cores in halted state.
> The Power Sleep Controller (PSC) module on K3 SoCs requires that the cores
> be in WFI/WFE states with no active bus transactions before the cores can
> be put back into reset. Support for this is provided by using the newly
> introduced .prepare() and .unprepare() ops in the remoteproc core. The
> .prepare() ops is invoked before any loading, and the .unprepare() ops
> is invoked after the remoteproc resource cleanup. The R5F core resets
> are deasserted in .prepare() and asserted in .unprepare(), and the cores
> themselves are started and halted in .start() and .stop() ops. This
> ensures symmetric usage and allows the R5F cores state machine to be
> maintained properly between using the sysfs 'state' variable, bind/unbind
> and regular module load/unload flows.
>
> The subsystem is represented as a single remoteproc in LockStep mode, and
> as two remoteprocs in Split mode. The driver uses various TI-SCI interfaces
> to talk to the System Controller (DMSC) for managing configuration, power
> and reset management of these cores. IPC between the A53 cores and the R5
> cores is supported through the virtio rpmsg stack using shared memory and
> OMAP Mailboxes.
>
> The AM65x SoCs typically have a single R5FSS in the MCU voltage domain. The
> J721E SoCs uses a slightly revised IP and typically have three R5FSSs, with
> one cluster present within the MCU voltage domain (MCU_R5FSS0), and the
> remaining two clusters present in the MAIN voltage domain (MAIN_R5FSS0 and
> MAIN_R5FSS1). The integration of these clusters on J721E SoC is also
> slightly different in that these IPs do support an actual local reset line,
> while they are a no-op on AM65x SoCs.
>
> Signed-off-by: Suman Anna <s-anna@ti.com>
> ---
> v2:
> - k3_r5_probe() adapted to use devm_ API completely eliminating
> k3_r5_remove()
> - k3_r5_cluster_of_init() and k3_r5_cluster_rproc_init() leverage
> devm_add_action_or_reset() to perform corresponding cleanup
> - Reordered k3_r5_cluster_of_exit() before k3_r5_cluster_of_init()
> to use it in the latter's failure path cleanup
> - Leverage devres groups in k3_r5_core_of_init() to use all devm_ API
> and simplify k3_r5_core_of_exit() greatly
> - k3_r5_core_of_get_internal_memories() failure path code cleaned up
> due to the devm_ adaptation
> - Added a function description around k3_r5_rproc_configure() and fixed
> up the halt logic for LockStep mode
> - Replaced the private k3_r5_rproc_get_firmware() with the common
> rproc_of_parse_firmware()
> - Adjusted to use the renamed properties for "lockstep-mode",
> "atcm-enable", "btcm-enable" and "loczrama"
> - Use dev_of_node() instead of direct dereferences for of_node
> - Addressed all other minor review comments from Mathieu. These include:
> 1. Fix the few headers that were not sorted in alphabetical order
> 2. Use enum in cluster->mode expressions
> 3. Adjust some dev_dbg traces and add comments around unsupported
> 64-bit addresses
> - Revised the patch title to move away from remoteproc/k3-r5
> - Cleanup the Kconfig help
> v1: https://patchwork.kernel.org/patch/11456375/
>
> drivers/remoteproc/Kconfig | 13 +
> drivers/remoteproc/Makefile | 1 +
> drivers/remoteproc/ti_k3_r5_remoteproc.c | 1304 ++++++++++++++++++++++
> 3 files changed, 1318 insertions(+)
> create mode 100644 drivers/remoteproc/ti_k3_r5_remoteproc.c
>
> diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
> index 74b818b25068..6e02cbcf8032 100644
> --- a/drivers/remoteproc/Kconfig
> +++ b/drivers/remoteproc/Kconfig
> @@ -262,6 +262,19 @@ 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_R5_REMOTEPROC
> + tristate "TI K3 R5 remoteproc support"
> + depends on ARCH_K3
> + select MAILBOX
> + select OMAP2PLUS_MBOX
> + help
> + Say m here to support TI's R5F 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 slave processor.
> +
> endif # REMOTEPROC
>
> endmenu
> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
> index d457d0f87ada..ebc7003b4bbf 100644
> --- a/drivers/remoteproc/Makefile
> +++ b/drivers/remoteproc/Makefile
> @@ -31,3 +31,4 @@ 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_R5_REMOTEPROC) += ti_k3_r5_remoteproc.o
> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> new file mode 100644
> index 000000000000..c4f99e59dc2f
> --- /dev/null
> +++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> @@ -0,0 +1,1304 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * TI K3 R5F (MCU) Remote Processor driver
> + *
> + * Copyright (C) 2017-2020 Texas Instruments Incorporated - http://www.ti.com/

You probably want to make this https to keep Alexander Kilmov's script happy.

> + * Suman Anna <s-anna@ti.com>
> + */
> +
> +#include <linux/dma-mapping.h>
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/mailbox_client.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_device.h>
> +#include <linux/of_reserved_mem.h>
> +#include <linux/omap-mailbox.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/remoteproc.h>
> +#include <linux/reset.h>
> +#include <linux/slab.h>
> +#include <linux/soc/ti/ti_sci_protocol.h>
> +
> +#include "omap_remoteproc.h"
> +#include "remoteproc_internal.h"
> +#include "ti_sci_proc.h"
> +
> +/* This address can either be for ATCM or BTCM with the other at address 0x0 */
> +#define K3_R5_TCM_DEV_ADDR 0x41010000
> +
> +/* R5 TI-SCI Processor Configuration Flags */
> +#define PROC_BOOT_CFG_FLAG_R5_DBG_EN 0x00000001
> +#define PROC_BOOT_CFG_FLAG_R5_DBG_NIDEN 0x00000002
> +#define PROC_BOOT_CFG_FLAG_R5_LOCKSTEP 0x00000100
> +#define PROC_BOOT_CFG_FLAG_R5_TEINIT 0x00000200
> +#define PROC_BOOT_CFG_FLAG_R5_NMFI_EN 0x00000400
> +#define PROC_BOOT_CFG_FLAG_R5_TCM_RSTBASE 0x00000800
> +#define PROC_BOOT_CFG_FLAG_R5_BTCM_EN 0x00001000
> +#define PROC_BOOT_CFG_FLAG_R5_ATCM_EN 0x00002000
> +
> +/* R5 TI-SCI Processor Control Flags */
> +#define PROC_BOOT_CTRL_FLAG_R5_CORE_HALT 0x00000001
> +
> +/* R5 TI-SCI Processor Status Flags */
> +#define PROC_BOOT_STATUS_FLAG_R5_WFE 0x00000001
> +#define PROC_BOOT_STATUS_FLAG_R5_WFI 0x00000002
> +#define PROC_BOOT_STATUS_FLAG_R5_CLK_GATED 0x00000004
> +#define PROC_BOOT_STATUS_FLAG_R5_LOCKSTEP_PERMITTED 0x00000100
> +
> +/**
> + * struct k3_r5_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 from remoteproc view
> + * @size: Size of the memory region
> + */
> +struct k3_r5_mem {
> + void __iomem *cpu_addr;
> + phys_addr_t bus_addr;
> + u32 dev_addr;
> + size_t size;
> +};
> +
> +enum cluster_mode {
> + CLUSTER_MODE_SPLIT = 0,
> + CLUSTER_MODE_LOCKSTEP,
> +};
> +
> +/**
> + * struct k3_r5_cluster - K3 R5F Cluster structure
> + * @dev: cached device pointer
> + * @mode: Mode to configure the Cluster - Split or LockStep
> + * @cores: list of R5 cores within the cluster
> + */
> +struct k3_r5_cluster {
> + struct device *dev;
> + enum cluster_mode mode;
> + struct list_head cores;
> +};
> +
> +/**
> + * struct k3_r5_core - K3 R5 core structure
> + * @elem: linked list item
> + * @dev: cached device pointer
> + * @rproc: rproc handle representing this core
> + * @mem: internal memory regions data
> + * @num_mems: number of internal memory regions
> + * @reset: reset control handle
> + * @tsp: TI-SCI processor control handle
> + * @ti_sci: TI-SCI handle
> + * @ti_sci_id: TI-SCI device identifier
> + * @atcm_enable: flag to control ATCM enablement
> + * @btcm_enable: flag to control BTCM enablement
> + * @loczrama: flag to dictate which TCM is at device address 0x0
> + */
> +struct k3_r5_core {
> + struct list_head elem;
> + struct device *dev;
> + struct rproc *rproc;
> + struct k3_r5_mem *mem;
> + int num_mems;
> + struct reset_control *reset;
> + struct ti_sci_proc *tsp;
> + const struct ti_sci_handle *ti_sci;
> + u32 ti_sci_id;
> + u32 atcm_enable;
> + u32 btcm_enable;
> + u32 loczrama;
> +};
> +
> +/**
> + * struct k3_r5_rproc - K3 remote processor state
> + * @dev: cached device pointer
> + * @cluster: cached pointer to parent cluster structure
> + * @mbox: mailbox channel handle
> + * @client: mailbox client to request the mailbox channel
> + * @rproc: rproc handle
> + * @core: cached pointer to r5 core structure being used
> + * @rmem: reserved memory regions data
> + * @num_rmems: number of reserved memory regions
> + */
> +struct k3_r5_rproc {
> + struct device *dev;
> + struct k3_r5_cluster *cluster;
> + struct mbox_chan *mbox;
> + struct mbox_client client;
> + struct rproc *rproc;
> + struct k3_r5_core *core;
> + struct k3_r5_mem *rmem;
> + int num_rmems;
> +};
> +
> +/**
> + * k3_r5_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 OMAP 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_r5_rproc_mbox_callback(struct mbox_client *client, void *data)
> +{
> + struct k3_r5_rproc *kproc = container_of(client, struct k3_r5_rproc,
> + client);
> + struct device *dev = kproc->rproc->dev.parent;
> + const char *name = kproc->rproc->name;
> + u32 msg = omap_mbox_message(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 R5F 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 a virtqueue */
> +static void k3_r5_rproc_kick(struct rproc *rproc, int vqid)
> +{
> + struct k3_r5_rproc *kproc = rproc->priv;
> + struct device *dev = rproc->dev.parent;
> + mbox_msg_t msg = (mbox_msg_t)vqid;
> + int ret;
> +
> + /* send the index of the triggered virtqueue in the mailbox payload */
> + ret = mbox_send_message(kproc->mbox, (void *)msg);
> + if (ret < 0)
> + dev_err(dev, "failed to send mailbox message, status = %d\n",
> + ret);
> +}
> +
> +static int k3_r5_split_reset(struct k3_r5_core *core)
> +{
> + int ret;
> +
> + ret = reset_control_assert(core->reset);
> + if (ret) {
> + dev_err(core->dev, "local-reset assert failed, ret = %d\n",
> + ret);
> + return ret;
> + }
> +
> + ret = core->ti_sci->ops.dev_ops.put_device(core->ti_sci,
> + core->ti_sci_id);
> + if (ret) {
> + dev_err(core->dev, "module-reset assert failed, ret = %d\n",
> + ret);
> + if (reset_control_deassert(core->reset))
> + dev_warn(core->dev, "local-reset deassert back failed\n");
> + }
> +
> + return ret;
> +}
> +
> +static int k3_r5_split_release(struct k3_r5_core *core)
> +{
> + int ret;
> +
> + ret = core->ti_sci->ops.dev_ops.get_device(core->ti_sci,
> + core->ti_sci_id);
> + if (ret) {
> + dev_err(core->dev, "module-reset deassert failed, ret = %d\n",
> + ret);
> + return ret;
> + }
> +
> + ret = reset_control_deassert(core->reset);
> + if (ret) {
> + dev_err(core->dev, "local-reset deassert failed, ret = %d\n",
> + ret);
> + if (core->ti_sci->ops.dev_ops.put_device(core->ti_sci,
> + core->ti_sci_id))
> + dev_warn(core->dev, "module-reset assert back failed\n");
> + }
> +
> + return ret;
> +}
> +
> +static int k3_r5_lockstep_reset(struct k3_r5_cluster *cluster)
> +{
> + struct k3_r5_core *core;
> + int ret;
> +
> + /* assert local reset on all applicable cores */
> + list_for_each_entry(core, &cluster->cores, elem) {
> + ret = reset_control_assert(core->reset);
> + if (ret) {
> + dev_err(core->dev, "local-reset assert failed, ret = %d\n",
> + ret);
> + core = list_prev_entry(core, elem);
> + goto unroll_local_reset;
> + }
> + }
> +
> + /* disable PSC modules on all applicable cores */
> + list_for_each_entry(core, &cluster->cores, elem) {
> + ret = core->ti_sci->ops.dev_ops.put_device(core->ti_sci,
> + core->ti_sci_id);
> + if (ret) {
> + dev_err(core->dev, "module-reset assert failed, ret = %d\n",
> + ret);
> + goto unroll_module_reset;
> + }
> + }
> +
> + return 0;
> +
> +unroll_module_reset:
> + list_for_each_entry_continue_reverse(core, &cluster->cores, elem) {
> + if (core->ti_sci->ops.dev_ops.put_device(core->ti_sci,
> + core->ti_sci_id))
> + dev_warn(core->dev, "module-reset assert back failed\n");
> + }
> + core = list_last_entry(&cluster->cores, struct k3_r5_core, elem);
> +unroll_local_reset:
> + list_for_each_entry_from_reverse(core, &cluster->cores, elem) {
> + if (reset_control_deassert(core->reset))
> + dev_warn(core->dev, "local-reset deassert back failed\n");
> + }
> +
> + return ret;
> +}
> +
> +static int k3_r5_lockstep_release(struct k3_r5_cluster *cluster)
> +{
> + struct k3_r5_core *core;
> + int ret;
> +
> + /* enable PSC modules on all applicable cores */
> + list_for_each_entry_reverse(core, &cluster->cores, elem) {
> + ret = core->ti_sci->ops.dev_ops.get_device(core->ti_sci,
> + core->ti_sci_id);
> + if (ret) {
> + dev_err(core->dev, "module-reset deassert failed, ret = %d\n",
> + ret);
> + core = list_next_entry(core, elem);
> + goto unroll_module_reset;
> + }
> + }
> +
> + /* deassert local reset on all applicable cores */
> + list_for_each_entry_reverse(core, &cluster->cores, elem) {
> + ret = reset_control_deassert(core->reset);
> + if (ret) {
> + dev_err(core->dev, "module-reset deassert failed, ret = %d\n",
> + ret);
> + goto unroll_local_reset;
> + }
> + }
> +
> + return 0;
> +
> +unroll_local_reset:
> + list_for_each_entry_continue(core, &cluster->cores, elem) {
> + if (reset_control_assert(core->reset))
> + dev_warn(core->dev, "local-reset assert back failed\n");
> + }
> + core = list_first_entry(&cluster->cores, struct k3_r5_core, elem);
> +unroll_module_reset:
> + list_for_each_entry_from(core, &cluster->cores, elem) {
> + if (core->ti_sci->ops.dev_ops.put_device(core->ti_sci,
> + core->ti_sci_id))
> + dev_warn(core->dev, "module-reset assert back failed\n");
> + }
> +
> + return ret;
> +}
> +
> +static inline int k3_r5_core_halt(struct k3_r5_core *core)
> +{
> + return ti_sci_proc_set_control(core->tsp,
> + PROC_BOOT_CTRL_FLAG_R5_CORE_HALT, 0);
> +}
> +
> +static inline int k3_r5_core_run(struct k3_r5_core *core)
> +{
> + return ti_sci_proc_set_control(core->tsp,
> + 0, PROC_BOOT_CTRL_FLAG_R5_CORE_HALT);
> +}
> +
> +/*
> + * The R5F cores have controls for both a reset and a halt/run. The code
> + * execution from DDR requires the initial boot-strapping code to be run
> + * from the internal TCMs. This function is used to release the resets on
> + * applicable cores to allow loading into the TCMs. 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 R5 cores run.
> + */
> +static int k3_r5_rproc_prepare(struct rproc *rproc)
> +{
> + struct k3_r5_rproc *kproc = rproc->priv;
> + struct k3_r5_cluster *cluster = kproc->cluster;
> + struct k3_r5_core *core = kproc->core;
> + struct device *dev = kproc->dev;
> + int ret;
> +
> + ret = (cluster->mode == CLUSTER_MODE_LOCKSTEP) ?
> + k3_r5_lockstep_release(cluster) : k3_r5_split_release(core);
> + if (ret)
> + dev_err(dev, "unable to enable cores for TCM 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
> + * resets on all applicable cores for the rproc device (depending on LockStep
> + * or Split mode). This completes the second portion of powering down the R5F
> + * cores. The cores themselves are only halted in the .stop() ops, and the
> + * .unprepare() ops is invoked by the remoteproc core after the remoteproc is
> + * stopped.
> + */
> +static int k3_r5_rproc_unprepare(struct rproc *rproc)
> +{
> + struct k3_r5_rproc *kproc = rproc->priv;
> + struct k3_r5_cluster *cluster = kproc->cluster;
> + struct k3_r5_core *core = kproc->core;
> + struct device *dev = kproc->dev;
> + int ret;
> +
> + ret = (cluster->mode == CLUSTER_MODE_LOCKSTEP) ?
> + k3_r5_lockstep_reset(cluster) : k3_r5_split_reset(core);
> + if (ret)
> + dev_err(dev, "unable to disable cores, ret = %d\n", ret);
> +
> + return ret;
> +}
> +
> +/*
> + * The R5F start sequence includes two different operations
> + * 1. Configure the boot vector for R5F core(s)
> + * 2. Unhalt/Run the R5F core(s)
> + *
> + * The sequence is different between LockStep and Split modes. The LockStep
> + * mode requires the boot vector to be configured only for Core0, and then
> + * unhalt both the cores to start the execution - Core1 needs to be unhalted
> + * first followed by Core0. The Split-mode requires that Core0 to be maintained
> + * always in a higher power state that Core1 (implying Core1 needs to be started
> + * always only after Core0 is started).

I'm very puzzled by the last sentence. In split mode the code is
instantiating two independent rproc but above the comment claim that in fact
they are not since Core0 needs to be started first. Moreover I don't see that
rule being enforced in the code - the split mode path only takes care of the
single core. Since you took the time to write the comment (and also for
k3_r5_rproc_sto()) I suspect that I'm missing information somewhere.

> + */
> +static int k3_r5_rproc_start(struct rproc *rproc)
> +{
> + struct k3_r5_rproc *kproc = rproc->priv;
> + struct k3_r5_cluster *cluster = kproc->cluster;
> + struct mbox_client *client = &kproc->client;
> + struct device *dev = kproc->dev;
> + struct k3_r5_core *core;
> + u32 boot_addr;
> + int ret;
> +
> + client->dev = dev;
> + client->tx_done = NULL;
> + client->rx_callback = k3_r5_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);
> + goto put_mbox;
> + }
> +
> + boot_addr = rproc->bootaddr;
> + /* TODO: add boot_addr sanity checking */
> + dev_dbg(dev, "booting R5F core using boot addr = 0x%x\n", boot_addr);
> +
> + /* boot vector need not be programmed for Core1 in LockStep mode */
> + core = kproc->core;
> + ret = ti_sci_proc_set_config(core->tsp, boot_addr, 0, 0);
> + if (ret)
> + goto put_mbox;
> +
> + /* unhalt/run all applicable cores */
> + if (cluster->mode == CLUSTER_MODE_LOCKSTEP) {
> + list_for_each_entry_reverse(core, &cluster->cores, elem) {
> + ret = k3_r5_core_run(core);
> + if (ret)
> + goto unroll_core_run;
> + }
> + } else {
> + ret = k3_r5_core_run(core);
> + if (ret)
> + goto put_mbox;
> + }
> +
> + return 0;
> +
> +unroll_core_run:
> + list_for_each_entry_continue(core, &cluster->cores, elem) {
> + if (k3_r5_core_halt(core))
> + dev_warn(core->dev, "core halt back failed\n");
> + }
> +put_mbox:
> + mbox_free_channel(kproc->mbox);
> + return ret;
> +}
> +
> +/*
> + * The R5F stop function includes the following operations
> + * 1. Halt R5F core(s)
> + *
> + * The sequence is different between LockStep and Split modes, and the order
> + * of cores the operations are performed are also in general reverse to that
> + * of the start function. The LockStep mode requires each operation to be
> + * performed first on Core0 followed by Core1. The Split-mode requires that
> + * Core0 to be maintained always in a higher power state that Core1 (implying
> + * Core1 needs to be stopped first before Core0).
> + *
> + * Note that the R5F halt operation in general is not effective when the R5F
> + * core is running, but is needed to make sure the core won't run after
> + * deasserting the reset the subsequent time. The asserting of reset can
> + * be done here, but is preferred to be done in the .unprepare() ops - this
> + * maintains the symmetric behavior between the .start(), .stop(), .prepare()
> + * and .unprepare() ops, and also balances them well between sysfs 'state'
> + * flow and device bind/unbind or module removal.
> + */
> +static int k3_r5_rproc_stop(struct rproc *rproc)
> +{
> + struct k3_r5_rproc *kproc = rproc->priv;
> + struct k3_r5_cluster *cluster = kproc->cluster;
> + struct k3_r5_core *core = kproc->core;
> + int ret;
> +
> + /* halt all applicable cores */
> + if (cluster->mode == CLUSTER_MODE_LOCKSTEP) {
> + list_for_each_entry(core, &cluster->cores, elem) {
> + ret = k3_r5_core_halt(core);
> + if (ret) {
> + core = list_prev_entry(core, elem);
> + goto unroll_core_halt;
> + }
> + }
> + } else {
> + ret = k3_r5_core_halt(core);
> + if (ret)
> + goto out;
> + }
> +
> + mbox_free_channel(kproc->mbox);
> +
> + return 0;
> +
> +unroll_core_halt:
> + list_for_each_entry_from_reverse(core, &cluster->cores, elem) {
> + if (k3_r5_core_run(core))
> + dev_warn(core->dev, "core run back failed\n");
> + }
> +out:
> + return ret;
> +}

All of the above is very platform specific and I certainly won't claim to
understand all the details. That being said the logic and error control path
are done properly.

> +
> +/*
> + * Internal Memory translation helper
> + *
> + * Custom function implementing the rproc .da_to_va ops to provide address
> + * translation (device address to kernel virtual address) for internal RAMs
> + * present in a DSP or IPU device). The translated addresses can be used
> + * either by the remoteproc core for loading, or by any rpmsg bus drivers.
> + */
> +static void *k3_r5_rproc_da_to_va(struct rproc *rproc, u64 da, size_t len)
> +{
> + struct k3_r5_rproc *kproc = rproc->priv;
> + struct k3_r5_core *core = kproc->core;
> + void __iomem *va = NULL;
> + phys_addr_t bus_addr;
> + u32 dev_addr, offset;
> + size_t size;
> + int i;
> +
> + if (len == 0)
> + return NULL;
> +
> + /* handle both R5 and SoC views of ATCM and BTCM */
> + for (i = 0; i < core->num_mems; i++) {
> + bus_addr = core->mem[i].bus_addr;
> + dev_addr = core->mem[i].dev_addr;
> + size = core->mem[i].size;
> +
> + /* handle R5-view addresses of TCMs */
> + if (da >= dev_addr && ((da + len) <= (dev_addr + size))) {
> + offset = da - dev_addr;
> + va = core->mem[i].cpu_addr + offset;
> + return (__force void *)va;
> + }
> +
> + /* handle SoC-view addresses of TCMs */
> + if (da >= bus_addr && ((da + len) <= (bus_addr + size))) {
> + offset = da - bus_addr;
> + va = core->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 const struct rproc_ops k3_r5_rproc_ops = {
> + .prepare = k3_r5_rproc_prepare,
> + .unprepare = k3_r5_rproc_unprepare,
> + .start = k3_r5_rproc_start,
> + .stop = k3_r5_rproc_stop,
> + .kick = k3_r5_rproc_kick,
> + .da_to_va = k3_r5_rproc_da_to_va,
> +};
> +
> +/*
> + * Internal R5F Core configuration
> + *
> + * Each R5FSS has a cluster-level setting for configuring the processor
> + * subsystem either in a safety/fault-tolerant LockStep mode or a performance
> + * oriented Split mode. Each R5F core has a number of settings to either
> + * enable/disable each of the TCMs, control which TCM appears at the R5F core's
> + * address 0x0. These settings need to be configured before the resets for the
> + * corresponding core are released. These settings are all protected and managed
> + * by the System Processor.
> + *
> + * This function is used to pre-configure these settings for each R5F core, and
> + * the configuration is all done through various ti_sci_proc functions that
> + * communicate with the System Processor. The function also ensures that both
> + * the cores are halted before the .prepare() step.
> + *
> + * The function is called from k3_r5_cluster_rproc_init() and is invoked either
> + * once (in LockStep mode) or twice (in Split mode). Support for LockStep-mode
> + * is dictated by an eFUSE register bit, and the config settings retrieved from
> + * DT are adjusted accordingly as per the permitted cluster mode. All cluster
> + * level settings like Cluster mode and TEINIT (exception handling state
> + * dictating ARM or Thumb mode) can only be set and retrieved using Core0.
> + *
> + * The function behavior is different based on the cluster mode. The R5F cores
> + * are configured independently as per their individual settings in Split mode.
> + * They are identically configured in LockStep mode using the primary Core0
> + * settings. However, some individual settings cannot be set in LockStep mode.
> + * This is overcome by switching to Split-mode initially and then programming
> + * both the cores with the same settings, before reconfiguing again for
> + * LockStep mode.
> + */
> +static int k3_r5_rproc_configure(struct k3_r5_rproc *kproc)
> +{
> + struct k3_r5_cluster *cluster = kproc->cluster;
> + struct device *dev = kproc->dev;
> + struct k3_r5_core *core0, *core, *temp;
> + u32 ctrl = 0, cfg = 0, stat = 0;
> + u32 set_cfg = 0, clr_cfg = 0;
> + u64 boot_vec = 0;
> + bool lockstep_en;
> + int ret;
> +
> + core0 = list_first_entry(&cluster->cores, struct k3_r5_core, elem);
> + core = (cluster->mode == CLUSTER_MODE_LOCKSTEP) ? core0 : kproc->core;
> +
> + ret = ti_sci_proc_get_status(core->tsp, &boot_vec, &cfg, &ctrl,
> + &stat);
> + if (ret < 0)
> + return ret;
> +
> + dev_dbg(dev, "boot_vector = 0x%llx, cfg = 0x%x ctrl = 0x%x stat = 0x%x\n",
> + boot_vec, cfg, ctrl, stat);
> +
> + lockstep_en = !!(stat & PROC_BOOT_STATUS_FLAG_R5_LOCKSTEP_PERMITTED);
> + if (!lockstep_en && cluster->mode == CLUSTER_MODE_LOCKSTEP) {
> + dev_err(cluster->dev, "lockstep mode not permitted, force configuring for split-mode\n");
> + cluster->mode = CLUSTER_MODE_SPLIT;
> + }
> +
> + /* always enable ARM mode and set boot vector to 0 */
> + boot_vec = 0x0;
> + if (core == core0) {
> + clr_cfg = PROC_BOOT_CFG_FLAG_R5_TEINIT;
> + /*
> + * LockStep configuration bit is Read-only on Split-mode _only_
> + * devices and system firmware will NACK any requests with the
> + * bit configured, so program it only on permitted devices
> + */
> + if (lockstep_en)
> + clr_cfg |= PROC_BOOT_CFG_FLAG_R5_LOCKSTEP;
> + }
> +
> + if (core->atcm_enable)
> + set_cfg |= PROC_BOOT_CFG_FLAG_R5_ATCM_EN;
> + else
> + clr_cfg |= PROC_BOOT_CFG_FLAG_R5_ATCM_EN;
> +
> + if (core->btcm_enable)
> + set_cfg |= PROC_BOOT_CFG_FLAG_R5_BTCM_EN;
> + else
> + clr_cfg |= PROC_BOOT_CFG_FLAG_R5_BTCM_EN;
> +
> + if (core->loczrama)
> + set_cfg |= PROC_BOOT_CFG_FLAG_R5_TCM_RSTBASE;
> + else
> + clr_cfg |= PROC_BOOT_CFG_FLAG_R5_TCM_RSTBASE;
> +
> + if (cluster->mode == CLUSTER_MODE_LOCKSTEP) {
> + /*
> + * work around system firmware limitations to make sure both
> + * cores are programmed symmetrically in LockStep. LockStep
> + * and TEINIT config is only allowed with Core0.
> + */
> + list_for_each_entry(temp, &cluster->cores, elem) {
> + ret = k3_r5_core_halt(temp);
> + if (ret)
> + goto out;
> +
> + if (temp != core) {
> + clr_cfg &= ~PROC_BOOT_CFG_FLAG_R5_LOCKSTEP;
> + clr_cfg &= ~PROC_BOOT_CFG_FLAG_R5_TEINIT;
> + }
> + ret = ti_sci_proc_set_config(temp->tsp, boot_vec,
> + set_cfg, clr_cfg);
> + if (ret)
> + goto out;
> + }
> +
> + set_cfg = PROC_BOOT_CFG_FLAG_R5_LOCKSTEP;
> + clr_cfg = 0;
> + ret = ti_sci_proc_set_config(core->tsp, boot_vec,
> + set_cfg, clr_cfg);
> + } else {
> + ret = k3_r5_core_halt(core);
> + if (ret)
> + goto out;
> +
> + ret = ti_sci_proc_set_config(core->tsp, boot_vec,
> + set_cfg, clr_cfg);
> + }
> +
> +out:
> + return ret;
> +}
> +
> +static int k3_r5_reserved_mem_init(struct k3_r5_rproc *kproc)
> +{
> + struct device *dev = kproc->dev;
> + struct device_node *np = dev_of_node(dev);
> + 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 have reserved memory regions, ret = %d\n",
> + num_rmems);
> + return -EINVAL;
> + }
> + if (num_rmems < 2) {
> + dev_err(dev, "device needs atleast 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, ret = %d\n",
> + ret);
> + return ret;
> + }
> +
> + num_rmems--;
> + kproc->rmem = kcalloc(num_rmems, sizeof(*kproc->rmem), GFP_KERNEL);
> + if (!kproc->rmem) {
> + ret = -ENOMEM;
> + goto release_rmem;
> + }
> +
> + /* 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) {
> + ret = -EINVAL;
> + goto unmap_rmem;
> + }
> +
> + rmem = of_reserved_mem_lookup(rmem_np);
> + if (!rmem) {
> + of_node_put(rmem_np);
> + ret = -EINVAL;
> + goto unmap_rmem;
> + }
> + of_node_put(rmem_np);
> +
> + kproc->rmem[i].bus_addr = rmem->base;
> + /*
> + * R5Fs do not have an MMU, but have a Region Address Translator
> + * (RAT) module that provides a fixed entry translation between
> + * the 32-bit processor addresses to 64-bit bus addresses. The
> + * RAT is programmable only by the R5F cores. Support for RAT
> + * is currently not supported, so 64-bit address regions are not
> + * supported. The absence of MMUs implies that the R5F device
> + * addresses/supported memory regions are restricted to 32-bit
> + * bus addresses, and are identical
> + */
> + kproc->rmem[i].dev_addr = (u32)rmem->base;
> + kproc->rmem[i].size = rmem->size;
> + kproc->rmem[i].cpu_addr = ioremap_wc(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);
> + ret = -ENOMEM;
> + goto unmap_rmem;
> + }
> +
> + 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;
> +
> +unmap_rmem:
> + for (i--; i >= 0; i--) {
> + if (kproc->rmem[i].cpu_addr)

Did you find a code path where cpu_addr is not valid? As far as I can tell
current memory regions are not processed because of the i-- as a start condition
in the for loop and previous allocations were successful.

> + iounmap(kproc->rmem[i].cpu_addr);
> + }
> + kfree(kproc->rmem);
> +release_rmem:
> + of_reserved_mem_device_release(dev);
> + return ret;
> +}
> +
> +static void k3_r5_reserved_mem_exit(struct k3_r5_rproc *kproc)
> +{
> + int i;
> +
> + for (i = 0; i < kproc->num_rmems; i++)
> + iounmap(kproc->rmem[i].cpu_addr);
> + kfree(kproc->rmem);
> +
> + of_reserved_mem_device_release(kproc->dev);
> +}
> +
> +static int k3_r5_cluster_rproc_init(struct platform_device *pdev)
> +{
> + struct k3_r5_cluster *cluster = platform_get_drvdata(pdev);
> + struct device *dev = &pdev->dev;
> + struct k3_r5_rproc *kproc;
> + struct k3_r5_core *core, *core1;
> + struct device *cdev;
> + const char *fw_name;
> + struct rproc *rproc;
> + int ret;
> +
> + core1 = list_last_entry(&cluster->cores, struct k3_r5_core, elem);
> + list_for_each_entry(core, &cluster->cores, elem) {
> + cdev = core->dev;
> + ret = rproc_of_parse_firmware(cdev, 0, &fw_name);
> + if (ret) {
> + dev_err(dev, "failed to parse firmware-name property, ret = %d\n",
> + ret);
> + goto out;
> + }
> +
> + rproc = rproc_alloc(cdev, dev_name(cdev), &k3_r5_rproc_ops,
> + fw_name, sizeof(*kproc));
> + if (!rproc) {
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> + /* K3 R5s have a Region Address Translator (RAT) but no MMU */
> + rproc->has_iommu = false;
> + /* error recovery is not supported at present */
> + rproc->recovery_disabled = true;
> +
> + kproc = rproc->priv;
> + kproc->cluster = cluster;
> + kproc->core = core;
> + kproc->dev = cdev;
> + kproc->rproc = rproc;
> + core->rproc = rproc;
> +
> + ret = k3_r5_rproc_configure(kproc);
> + if (ret) {
> + dev_err(dev, "initial configure failed, ret = %d\n",
> + ret);
> + goto err_config;
> + }
> +
> + ret = k3_r5_reserved_mem_init(kproc);
> + if (ret) {
> + dev_err(dev, "reserved memory init failed, ret = %d\n",
> + ret);
> + goto err_config;
> + }
> +
> + ret = rproc_add(rproc);
> + if (ret) {
> + dev_err(dev, "rproc_add failed, ret = %d\n", ret);
> + goto err_add;
> + }
> +
> + /* create only one rproc in lockstep mode */
> + if (cluster->mode == CLUSTER_MODE_LOCKSTEP)
> + break;
> + }
> +
> + return 0;
> +
> +err_split:
> + rproc_del(rproc);
> +err_add:
> + k3_r5_reserved_mem_exit(kproc);
> +err_config:
> + rproc_free(rproc);
> + core->rproc = NULL;
> +out:
> + /* undo core0 upon any failures on core1 in split-mode */
> + if (cluster->mode == CLUSTER_MODE_SPLIT && core == core1) {
> + core = list_prev_entry(core, elem);
> + rproc = core->rproc;
> + kproc = rproc->priv;
> + goto err_split;
> + }
> + return ret;
> +}
> +
> +static int k3_r5_cluster_rproc_exit(struct platform_device *pdev)
> +{
> + struct k3_r5_cluster *cluster = platform_get_drvdata(pdev);
> + struct k3_r5_rproc *kproc;
> + struct k3_r5_core *core;
> + struct rproc *rproc;
> +
> + /*
> + * lockstep mode has only one rproc associated with first core, whereas
> + * split-mode has two rprocs associated with each core, and requires
> + * that core1 be powered down first
> + */
> + core = (cluster->mode == CLUSTER_MODE_LOCKSTEP) ?
> + list_first_entry(&cluster->cores, struct k3_r5_core, elem) :
> + list_last_entry(&cluster->cores, struct k3_r5_core, elem);
> +
> + list_for_each_entry_from_reverse(core, &cluster->cores, elem) {
> + rproc = core->rproc;
> + kproc = rproc->priv;
> +
> + rproc_del(rproc);
> +
> + k3_r5_reserved_mem_exit(kproc);
> +
> + rproc_free(rproc);
> + core->rproc = NULL;
> + }
> +
> + return 0;
> +}
> +
> +static int k3_r5_core_of_get_internal_memories(struct platform_device *pdev,
> + struct k3_r5_core *core)
> +{
> + static const char * const mem_names[] = {"atcm", "btcm"};
> + struct device *dev = &pdev->dev;
> + struct resource *res;
> + int num_mems;
> + int i;
> +
> + num_mems = ARRAY_SIZE(mem_names);
> + core->mem = devm_kcalloc(dev, num_mems, sizeof(*core->mem), GFP_KERNEL);
> + if (!core->mem)
> + return -ENOMEM;
> +
> + for (i = 0; i < num_mems; i++) {
> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> + mem_names[i]);
> + if (!res) {
> + dev_err(dev, "found no memory resource for %s\n",
> + mem_names[i]);
> + 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",
> + mem_names[i]);
> + return -EBUSY;
> + }
> +
> + /*
> + * TCMs are designed in general to support RAM-like backing
> + * memories. So, map these as Normal Non-Cached memories. This
> + * also avoids/fixes any potential alignment faults due to
> + * unaligned data accesses when using memcpy() or memset()
> + * functions (normally seen with device type memory).
> + */
> + core->mem[i].cpu_addr = devm_ioremap_wc(dev, res->start,
> + resource_size(res));
> + if (IS_ERR(core->mem[i].cpu_addr)) {
> + dev_err(dev, "failed to map %s memory\n", mem_names[i]);
> + return PTR_ERR(core->mem[i].cpu_addr);
> + }
> + core->mem[i].bus_addr = res->start;
> +
> + /*
> + * TODO:
> + * The R5F cores can place ATCM & BTCM anywhere in its address
> + * based on the corresponding Region Registers in the System
> + * Control coprocessor. For now, place ATCM and BTCM at
> + * addresses 0 and 0x41010000 (same as the bus address on AM65x
> + * SoCs) based on loczrama setting
> + */
> + if (!strcmp(mem_names[i], "atcm")) {
> + core->mem[i].dev_addr = core->loczrama ?
> + 0 : K3_R5_TCM_DEV_ADDR;
> + } else {
> + core->mem[i].dev_addr = core->loczrama ?
> + K3_R5_TCM_DEV_ADDR : 0;
> + }
> + core->mem[i].size = resource_size(res);
> +
> + dev_dbg(dev, "memory %5s: bus addr %pa size 0x%zx va %pK da 0x%x\n",
> + mem_names[i], &core->mem[i].bus_addr,
> + core->mem[i].size, core->mem[i].cpu_addr,
> + core->mem[i].dev_addr);
> + }
> + core->num_mems = num_mems;
> +
> + return 0;
> +}
> +
> +static
> +struct ti_sci_proc *k3_r5_core_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(dev), "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 int k3_r5_core_of_init(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct device_node *np = dev_of_node(dev);
> + struct k3_r5_core *core;
> + int ret;
> +
> + if (!devres_open_group(dev, k3_r5_core_of_init, GFP_KERNEL))
> + return -ENOMEM;
> +
> + core = devm_kzalloc(dev, sizeof(*core), GFP_KERNEL);
> + if (!core) {
> + ret = -ENOMEM;
> + goto err;
> + }
> +
> + core->dev = dev;
> + /*
> + * Use SoC Power-on-Reset values as default if no DT properties are
> + * used to dictate the TCM configurations
> + */
> + core->atcm_enable = 0;
> + core->btcm_enable = 1;
> + core->loczrama = 1;
> +
> + ret = of_property_read_u32(np, "ti,atcm-enable", &core->atcm_enable);
> + if (ret < 0 && ret != -EINVAL) {
> + dev_err(dev, "invalid format for ti,atcm-enable, ret = %d\n",
> + ret);
> + goto err;
> + }
> +
> + ret = of_property_read_u32(np, "ti,btcm-enable", &core->btcm_enable);
> + if (ret < 0 && ret != -EINVAL) {
> + dev_err(dev, "invalid format for ti,btcm-enable, ret = %d\n",
> + ret);
> + goto err;
> + }
> +
> + ret = of_property_read_u32(np, "ti,loczrama", &core->loczrama);
> + if (ret < 0 && ret != -EINVAL) {
> + dev_err(dev, "invalid format for ti,loczrama, ret = %d\n", ret);
> + goto err;
> + }
> +
> + core->ti_sci = devm_ti_sci_get_by_phandle(dev, "ti,sci");
> + if (IS_ERR(core->ti_sci)) {
> + ret = PTR_ERR(core->ti_sci);
> + if (ret != -EPROBE_DEFER) {
> + dev_err(dev, "failed to get ti-sci handle, ret = %d\n",
> + ret);
> + }
> + core->ti_sci = NULL;
> + goto err;
> + }
> +
> + ret = of_property_read_u32(np, "ti,sci-dev-id", &core->ti_sci_id);
> + if (ret) {
> + dev_err(dev, "missing 'ti,sci-dev-id' property\n");
> + goto err;
> + }
> +
> + core->reset = devm_reset_control_get_exclusive(dev, NULL);
> + if (IS_ERR(core->reset)) {

IS_ERR_OR_NULL() since devm_reset_control_get_exclusive() can return NULL.

Otherwise I am pleased with how you have refactored this driver to use the device
management mechanic to take care of tedious error paths. Aside from the above
minor details I haven't found much to frown at. With this much code I could
find things to pick at but nothing serious enough to delay this set.

With the above:

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>

> + ret = PTR_ERR(core->reset);
> + if (ret != -EPROBE_DEFER) {
> + dev_err(dev, "failed to get reset handle, ret = %d\n",
> + ret);
> + }
> + goto err;
> + }
> +
> + core->tsp = k3_r5_core_of_get_tsp(dev, core->ti_sci);
> + if (IS_ERR(core->tsp)) {
> + dev_err(dev, "failed to construct ti-sci proc control, ret = %d\n",
> + ret);
> + ret = PTR_ERR(core->tsp);
> + goto err;
> + }
> +
> + ret = k3_r5_core_of_get_internal_memories(pdev, core);
> + if (ret) {
> + dev_err(dev, "failed to get internal memories, ret = %d\n",
> + ret);
> + goto err;
> + }
> +
> + ret = ti_sci_proc_request(core->tsp);
> + if (ret < 0) {
> + dev_err(dev, "ti_sci_proc_request failed, ret = %d\n", ret);
> + goto err;
> + }
> +
> + platform_set_drvdata(pdev, core);
> + devres_close_group(dev, k3_r5_core_of_init);
> +
> + return 0;
> +
> +err:
> + devres_release_group(dev, k3_r5_core_of_init);
> + return ret;
> +}
> +
> +/*
> + * free the resources explicitly since driver model is not being used
> + * for the child R5F devices
> + */
> +static void k3_r5_core_of_exit(struct platform_device *pdev)
> +{
> + struct k3_r5_core *core = platform_get_drvdata(pdev);
> + struct device *dev = &pdev->dev;
> + int ret;
> +
> + ret = ti_sci_proc_release(core->tsp);
> + if (ret)
> + dev_err(dev, "failed to release proc, ret = %d\n", ret);
> +
> + platform_set_drvdata(pdev, NULL);
> + devres_release_group(dev, k3_r5_core_of_init);
> +}
> +
> +static void k3_r5_cluster_of_exit(struct platform_device *pdev)
> +{
> + struct k3_r5_cluster *cluster = platform_get_drvdata(pdev);
> + struct platform_device *cpdev;
> + struct k3_r5_core *core, *temp;
> +
> + list_for_each_entry_safe_reverse(core, temp, &cluster->cores, elem) {
> + list_del(&core->elem);
> + cpdev = to_platform_device(core->dev);
> + k3_r5_core_of_exit(cpdev);
> + }
> +}
> +
> +static int k3_r5_cluster_of_init(struct platform_device *pdev)
> +{
> + struct k3_r5_cluster *cluster = platform_get_drvdata(pdev);
> + struct device *dev = &pdev->dev;
> + struct device_node *np = dev_of_node(dev);
> + struct platform_device *cpdev;
> + struct device_node *child;
> + struct k3_r5_core *core;
> + int ret;
> +
> + for_each_available_child_of_node(np, child) {
> + cpdev = of_find_device_by_node(child);
> + if (!cpdev) {
> + ret = -ENODEV;
> + dev_err(dev, "could not get R5 core platform device\n");
> + goto fail;
> + }
> +
> + ret = k3_r5_core_of_init(cpdev);
> + if (ret) {
> + dev_err(dev, "k3_r5_core_of_init failed, ret = %d\n",
> + ret);
> + put_device(&cpdev->dev);
> + goto fail;
> + }
> +
> + core = platform_get_drvdata(cpdev);
> + put_device(&cpdev->dev);
> + list_add_tail(&core->elem, &cluster->cores);
> + }
> +
> + return 0;
> +
> +fail:
> + k3_r5_cluster_of_exit(pdev);
> + return ret;
> +}
> +
> +static int k3_r5_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct device_node *np = dev_of_node(dev);
> + struct k3_r5_cluster *cluster;
> + int ret;
> + int num_cores;
> +
> + cluster = devm_kzalloc(dev, sizeof(*cluster), GFP_KERNEL);
> + if (!cluster)
> + return -ENOMEM;
> +
> + cluster->dev = dev;
> + cluster->mode = CLUSTER_MODE_LOCKSTEP;
> + INIT_LIST_HEAD(&cluster->cores);
> +
> + ret = of_property_read_u32(np, "ti,cluster-mode", &cluster->mode);
> + if (ret < 0 && ret != -EINVAL) {
> + dev_err(dev, "invalid format for ti,cluster-mode, ret = %d\n",
> + ret);
> + return ret;
> + }
> +
> + num_cores = of_get_available_child_count(np);
> + if (num_cores != 2) {
> + dev_err(dev, "MCU cluster requires both R5F cores to be enabled, num_cores = %d\n",
> + num_cores);
> + return -ENODEV;
> + }
> +
> + platform_set_drvdata(pdev, cluster);
> +
> + ret = devm_of_platform_populate(dev);
> + if (ret) {
> + dev_err(dev, "devm_of_platform_populate failed, ret = %d\n",
> + ret);
> + return ret;
> + }
> +
> + ret = k3_r5_cluster_of_init(pdev);
> + if (ret) {
> + dev_err(dev, "k3_r5_cluster_of_init failed, ret = %d\n", ret);
> + return ret;
> + }
> +
> + ret = devm_add_action_or_reset(dev,
> + (void(*)(void *))k3_r5_cluster_of_exit,
> + pdev);
> + if (ret)
> + return ret;
> +
> + ret = k3_r5_cluster_rproc_init(pdev);
> + if (ret) {
> + dev_err(dev, "k3_r5_cluster_rproc_init failed, ret = %d\n",
> + ret);
> + return ret;
> + }
> +
> + ret = devm_add_action_or_reset(dev,
> + (void(*)(void *))k3_r5_cluster_rproc_exit,
> + pdev);
> + if (ret)
> + return ret;
> +
> + return 0;
> +}
> +
> +static const struct of_device_id k3_r5_of_match[] = {
> + { .compatible = "ti,am654-r5fss", },
> + { .compatible = "ti,j721e-r5fss", },
> + { /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, k3_r5_of_match);
> +
> +static struct platform_driver k3_r5_rproc_driver = {
> + .probe = k3_r5_probe,
> + .driver = {
> + .name = "k3_r5_rproc",
> + .of_match_table = k3_r5_of_match,
> + },
> +};
> +
> +module_platform_driver(k3_r5_rproc_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("TI K3 R5F remote processor driver");
> +MODULE_AUTHOR("Suman Anna <s-anna@ti.com>");
> --
> 2.26.0
>