[PATCH v2 3/5] remoteproc: k3-r5: Add support for IPC-only mode for all R5Fs
Mathieu Poirier
mathieu.poirier at linaro.org
Mon Aug 2 11:25:57 PDT 2021
On Fri, Jul 23, 2021 at 05:02:46PM -0500, Suman Anna wrote:
> Add support to the K3 R5F remoteproc driver to configure all the R5F
> cores to be either in IPC-only mode or the traditional remoteproc mode.
> The IPC-only mode expects that the remote processors are already booted
> by the bootloader, and only performs the minimum steps required to
> initialize and deinitialize the virtio IPC transports. The remoteproc
> mode allows the kernel remoteproc driver to do the regular load and
> boot and other device management operations for a R5F core.
>
> The IPC-only mode for a R5F core is detected and configured at driver
> probe time by querying the System Firmware for the R5F power and reset
> state and/or status and making sure that the R5F core is indeed started
> by the bootloaders, otherwise the device is configured for remoteproc
> mode.
>
> Support for IPC-only mode is achieved through .attach(), .detach() and
> .get_loaded_rsc_table() callback ops and zeroing out the regular rproc
> ops .prepare(), .unprepare(), .start() and .stop(). The resource table
> follows a design-by-contract approach and is expected to be at the base
> of the DDR firmware region reserved for each remoteproc, it is mostly
> expected to contain only the virtio device and trace resource entries.
>
> NOTE:
> The driver cannot configure a R5F core for remoteproc mode by any
> means without rebooting the kernel if that R5F core has been started
> by a bootloader. This is the current desired behavior and can be
> enhanced in the future if the feature is needed.
>
> Signed-off-by: Suman Anna <s-anna at ti.com>
> ---
> v2: Addressed various review comments from v1
> - Reworked the logic to not use remoteproc detach_on_shutdown and
> local ipc-only state flags
> - Plugged in the required IPC-only ops dynamically with the regular
> remoteproc-mode ops zeroed out
> - Dropped all the unneeded error checks in start, stop, prepare,
> unprepare, attach and detach callbacks
> - Callback function descriptions updated to reflect the mode they
> apply to
> - Switched to dev_info for the mode information traces from dev_err
> - Revised the last 2 paras of the patch description
> v1: https://patchwork.kernel.org/project/linux-remoteproc/patch/20210522000309.26134-5-s-anna@ti.com/
>
> drivers/remoteproc/ti_k3_r5_remoteproc.c | 199 ++++++++++++++++++++++-
> 1 file changed, 196 insertions(+), 3 deletions(-)
>
Reviewed-by: Mathieu Poirier <mathieu.poirier at linaro.org>
> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> index 03f930758b2d..12658368aed6 100644
> --- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
> +++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> @@ -428,6 +428,7 @@ static int k3_r5_rproc_request_mbox(struct rproc *rproc)
> * private to each core. Only Core0 needs to be unhalted for running the
> * cluster in this mode. The function uses the same reset logic as LockStep
> * mode for this (though the behavior is agnostic of the reset release order).
> + * This callback is invoked only in remoteproc mode.
> */
> static int k3_r5_rproc_prepare(struct rproc *rproc)
> {
> @@ -493,7 +494,8 @@ static int k3_r5_rproc_prepare(struct rproc *rproc)
> * both cores. The access is made possible only with releasing the resets for
> * both cores, but with only Core0 unhalted. This function re-uses the same
> * reset assert logic as LockStep mode for this mode (though the behavior is
> - * agnostic of the reset assert order).
> + * agnostic of the reset assert order). This callback is invoked only in
> + * remoteproc mode.
> */
> static int k3_r5_rproc_unprepare(struct rproc *rproc)
> {
> @@ -527,7 +529,8 @@ static int k3_r5_rproc_unprepare(struct rproc *rproc)
> *
> * The Single-CPU mode on applicable SoCs (eg: AM64x) only uses Core0 to execute
> * code, so only Core0 needs to be unhalted. The function uses the same logic
> - * flow as Split-mode for this.
> + * flow as Split-mode for this. This callback is invoked only in remoteproc
> + * mode.
> */
> static int k3_r5_rproc_start(struct rproc *rproc)
> {
> @@ -598,7 +601,8 @@ static int k3_r5_rproc_start(struct rproc *rproc)
> * 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.
> + * flow and device bind/unbind or module removal. This callback is invoked
> + * only in remoteproc mode.
> */
> static int k3_r5_rproc_stop(struct rproc *rproc)
> {
> @@ -635,6 +639,78 @@ static int k3_r5_rproc_stop(struct rproc *rproc)
> return ret;
> }
>
> +/*
> + * Attach to a running R5F remote processor (IPC-only mode)
> + *
> + * The R5F attach callback only needs to request the mailbox, the remote
> + * processor is already booted, so there is no need to issue any TI-SCI
> + * commands to boot the R5F cores in IPC-only mode. This callback is invoked
> + * only in IPC-only mode.
> + */
> +static int k3_r5_rproc_attach(struct rproc *rproc)
> +{
> + struct k3_r5_rproc *kproc = rproc->priv;
> + struct device *dev = kproc->dev;
> + int ret;
> +
> + ret = k3_r5_rproc_request_mbox(rproc);
> + if (ret)
> + return ret;
> +
> + dev_info(dev, "R5F core initialized in IPC-only mode\n");
> + return 0;
> +}
> +
> +/*
> + * Detach from a running R5F remote processor (IPC-only mode)
> + *
> + * The R5F detach callback performs the opposite operation to attach callback
> + * and only needs to release the mailbox, the R5F cores are not stopped and
> + * will be left in booted state in IPC-only mode. This callback is invoked
> + * only in IPC-only mode.
> + */
> +static int k3_r5_rproc_detach(struct rproc *rproc)
> +{
> + struct k3_r5_rproc *kproc = rproc->priv;
> + struct device *dev = kproc->dev;
> +
> + mbox_free_channel(kproc->mbox);
> + dev_info(dev, "R5F core deinitialized in IPC-only mode\n");
> + return 0;
> +}
> +
> +/*
> + * This function implements the .get_loaded_rsc_table() callback and is used
> + * to provide the resource table for the booted R5F in IPC-only mode. The K3 R5F
> + * firmwares follow a design-by-contract approach and are expected to have the
> + * resource table at the base of the DDR region reserved for firmware usage.
> + * This provides flexibility for the remote processor to be booted by different
> + * bootloaders that may or may not have the ability to publish the resource table
> + * address and size through a DT property. This callback is invoked only in
> + * IPC-only mode.
> + */
> +static struct resource_table *k3_r5_get_loaded_rsc_table(struct rproc *rproc,
> + size_t *rsc_table_sz)
> +{
> + struct k3_r5_rproc *kproc = rproc->priv;
> + struct device *dev = kproc->dev;
> +
> + if (!kproc->rmem[0].cpu_addr) {
> + dev_err(dev, "memory-region #1 does not exist, loaded rsc table can't be found");
> + return ERR_PTR(-ENOMEM);
> + }
> +
> + /*
> + * NOTE: The resource table size is currently hard-coded to a maximum
> + * of 256 bytes. The most common resource table usage for K3 firmwares
> + * is to only have the vdev resource entry and an optional trace entry.
> + * The exact size could be computed based on resource table address, but
> + * the hard-coded value suffices to support the IPC-only mode.
> + */
> + *rsc_table_sz = 256;
> + return (struct resource_table *)kproc->rmem[0].cpu_addr;
> +}
> +
> /*
> * Internal Memory translation helper
> *
> @@ -1014,6 +1090,116 @@ static void k3_r5_adjust_tcm_sizes(struct k3_r5_rproc *kproc)
> }
> }
>
> +/*
> + * This function checks and configures a R5F core for IPC-only or remoteproc
> + * mode. The driver is configured to be in IPC-only mode for a R5F core when
> + * the core has been loaded and started by a bootloader. The IPC-only mode is
> + * detected by querying the System Firmware for reset, power on and halt status
> + * and ensuring that the core is running. Any incomplete steps at bootloader
> + * are validated and errored out.
> + *
> + * In IPC-only mode, the driver state flags for ATCM, BTCM and LOCZRAMA settings
> + * and cluster mode parsed originally from kernel DT are updated to reflect the
> + * actual values configured by bootloader. The driver internal device memory
> + * addresses for TCMs are also updated.
> + */
> +static int k3_r5_rproc_configure_mode(struct k3_r5_rproc *kproc)
> +{
> + struct k3_r5_cluster *cluster = kproc->cluster;
> + struct k3_r5_core *core = kproc->core;
> + struct device *cdev = core->dev;
> + bool r_state = false, c_state = false;
> + u32 ctrl = 0, cfg = 0, stat = 0, halted = 0;
> + u64 boot_vec = 0;
> + u32 atcm_enable, btcm_enable, loczrama;
> + struct k3_r5_core *core0;
> + enum cluster_mode mode;
> + int ret;
> +
> + core0 = list_first_entry(&cluster->cores, struct k3_r5_core, elem);
> +
> + ret = core->ti_sci->ops.dev_ops.is_on(core->ti_sci, core->ti_sci_id,
> + &r_state, &c_state);
> + if (ret) {
> + dev_err(cdev, "failed to get initial state, mode cannot be determined, ret = %d\n",
> + ret);
> + return ret;
> + }
> + if (r_state != c_state) {
> + dev_warn(cdev, "R5F core may have been powered on by a different host, programmed state (%d) != actual state (%d)\n",
> + r_state, c_state);
> + }
> +
> + ret = reset_control_status(core->reset);
> + if (ret < 0) {
> + dev_err(cdev, "failed to get initial local reset status, ret = %d\n",
> + ret);
> + return ret;
> + }
> +
> + ret = ti_sci_proc_get_status(core->tsp, &boot_vec, &cfg, &ctrl,
> + &stat);
> + if (ret < 0) {
> + dev_err(cdev, "failed to get initial processor status, ret = %d\n",
> + ret);
> + return ret;
> + }
> + atcm_enable = cfg & PROC_BOOT_CFG_FLAG_R5_ATCM_EN ? 1 : 0;
> + btcm_enable = cfg & PROC_BOOT_CFG_FLAG_R5_BTCM_EN ? 1 : 0;
> + loczrama = cfg & PROC_BOOT_CFG_FLAG_R5_TCM_RSTBASE ? 1 : 0;
> + if (cluster->soc_data->single_cpu_mode) {
> + mode = cfg & PROC_BOOT_CFG_FLAG_R5_SINGLE_CORE ?
> + CLUSTER_MODE_SINGLECPU : CLUSTER_MODE_SPLIT;
> + } else {
> + mode = cfg & PROC_BOOT_CFG_FLAG_R5_LOCKSTEP ?
> + CLUSTER_MODE_LOCKSTEP : CLUSTER_MODE_SPLIT;
> + }
> + halted = ctrl & PROC_BOOT_CTRL_FLAG_R5_CORE_HALT;
> +
> + /*
> + * IPC-only mode detection requires both local and module resets to
> + * be deasserted and R5F core to be unhalted. Local reset status is
> + * irrelevant if module reset is asserted (POR value has local reset
> + * deasserted), and is deemed as remoteproc mode
> + */
> + if (c_state && !ret && !halted) {
> + dev_info(cdev, "configured R5F for IPC-only mode\n");
> + kproc->rproc->state = RPROC_DETACHED;
> + ret = 1;
> + /* override rproc ops with only required IPC-only mode ops */
> + kproc->rproc->ops->prepare = NULL;
> + kproc->rproc->ops->unprepare = NULL;
> + kproc->rproc->ops->start = NULL;
> + kproc->rproc->ops->stop = NULL;
> + kproc->rproc->ops->attach = k3_r5_rproc_attach;
> + kproc->rproc->ops->detach = k3_r5_rproc_detach;
> + kproc->rproc->ops->get_loaded_rsc_table =
> + k3_r5_get_loaded_rsc_table;
> + } else if (!c_state) {
> + dev_info(cdev, "configured R5F for remoteproc mode\n");
> + ret = 0;
> + } else {
> + dev_err(cdev, "mismatched mode: local_reset = %s, module_reset = %s, core_state = %s\n",
> + !ret ? "deasserted" : "asserted",
> + c_state ? "deasserted" : "asserted",
> + halted ? "halted" : "unhalted");
> + ret = -EINVAL;
> + }
> +
> + /* fixup TCMs, cluster & core flags to actual values in IPC-only mode */
> + if (ret > 0) {
> + if (core == core0)
> + cluster->mode = mode;
> + core->atcm_enable = atcm_enable;
> + core->btcm_enable = btcm_enable;
> + core->loczrama = loczrama;
> + core->mem[0].dev_addr = loczrama ? 0 : K3_R5_TCM_DEV_ADDR;
> + core->mem[1].dev_addr = loczrama ? K3_R5_TCM_DEV_ADDR : 0;
> + }
> +
> + return ret;
> +}
> +
> static int k3_r5_cluster_rproc_init(struct platform_device *pdev)
> {
> struct k3_r5_cluster *cluster = platform_get_drvdata(pdev);
> @@ -1054,6 +1240,12 @@ static int k3_r5_cluster_rproc_init(struct platform_device *pdev)
> kproc->rproc = rproc;
> core->rproc = rproc;
>
> + ret = k3_r5_rproc_configure_mode(kproc);
> + if (ret < 0)
> + goto err_config;
> + if (ret)
> + goto init_rmem;
> +
> ret = k3_r5_rproc_configure(kproc);
> if (ret) {
> dev_err(dev, "initial configure failed, ret = %d\n",
> @@ -1061,6 +1253,7 @@ static int k3_r5_cluster_rproc_init(struct platform_device *pdev)
> goto err_config;
> }
>
> +init_rmem:
> k3_r5_adjust_tcm_sizes(kproc);
>
> ret = k3_r5_reserved_mem_init(kproc);
> --
> 2.32.0
>
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