ARM: 9480/1: entry: expand comment in __switch_tografted

As per discussion between the developers in the mail thread
linked, expand the comment in __switch_to so that readers
of the code understand what is going on.

Suggested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Linus Walleij <linusw@kernel.org>>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

1 files changed, 281 insertions, 0 deletions

diff --git a/drivers/fwctl/bnxt/main.c b/drivers/fwctl/bnxt/main.c
new file mode 100644
index 000000000..951c8ac2e
--- /dev/null
+++ b/drivers/fwctl/bnxt/main.c
@@ -0,0 +1,281 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2026, Broadcom Corporation
+ */
+
+#include <linux/auxiliary_bus.h>
+#include <linux/slab.h>
+#include <linux/pci.h>
+#include <linux/fwctl.h>
+#include <linux/bnxt/hsi.h>
+#include <linux/bnxt/ulp.h>
+#include <uapi/fwctl/fwctl.h>
+#include <uapi/fwctl/bnxt.h>
+
+struct bnxtctl_uctx {
+	struct fwctl_uctx uctx;
+	u32 uctx_caps;
+};
+
+struct bnxtctl_dev {
+	struct fwctl_device fwctl;
+	struct bnxt_aux_priv *aux_priv;
+};
+
+DEFINE_FREE(bnxtctl, struct bnxtctl_dev *, if (_T) fwctl_put(&_T->fwctl))
+
+static int bnxtctl_open_uctx(struct fwctl_uctx *uctx)
+{
+	struct bnxtctl_uctx *bnxtctl_uctx =
+		container_of(uctx, struct bnxtctl_uctx, uctx);
+
+	bnxtctl_uctx->uctx_caps = BIT(FWCTL_BNXT_INLINE_COMMANDS) |
+				  BIT(FWCTL_BNXT_QUERY_COMMANDS) |
+				  BIT(FWCTL_BNXT_SEND_COMMANDS);
+	return 0;
+}
+
+static void bnxtctl_close_uctx(struct fwctl_uctx *uctx)
+{
+}
+
+static void *bnxtctl_info(struct fwctl_uctx *uctx, size_t *length)
+{
+	struct bnxtctl_uctx *bnxtctl_uctx =
+		container_of(uctx, struct bnxtctl_uctx, uctx);
+	struct fwctl_info_bnxt *info;
+
+	info = kzalloc_obj(*info);
+	if (!info)
+		return ERR_PTR(-ENOMEM);
+
+	info->uctx_caps = bnxtctl_uctx->uctx_caps;
+
+	*length = sizeof(*info);
+	return info;
+}
+
+/* Caller must hold edev->en_dev_lock */
+static bool bnxtctl_validate_rpc(struct bnxt_en_dev *edev,
+				 struct bnxt_fw_msg *hwrm_in,
+				 enum fwctl_rpc_scope scope)
+{
+	struct input *req = (struct input *)hwrm_in->msg;
+
+	lockdep_assert_held(&edev->en_dev_lock);
+	if (edev->flags & BNXT_EN_FLAG_ULP_STOPPED)
+		return false;
+
+	switch (le16_to_cpu(req->req_type)) {
+	case HWRM_FUNC_RESET:
+	case HWRM_PORT_CLR_STATS:
+	case HWRM_FW_RESET:
+	case HWRM_FW_SYNC:
+	case HWRM_FW_SET_TIME:
+	case HWRM_DBG_LOG_BUFFER_FLUSH:
+	case HWRM_DBG_ERASE_NVM:
+	case HWRM_DBG_CFG:
+	case HWRM_NVM_DEFRAG:
+	case HWRM_NVM_FACTORY_DEFAULTS:
+	case HWRM_NVM_FLUSH:
+	case HWRM_NVM_VERIFY_UPDATE:
+	case HWRM_NVM_ERASE_DIR_ENTRY:
+	case HWRM_NVM_MOD_DIR_ENTRY:
+	case HWRM_NVM_FIND_DIR_ENTRY:
+		return scope >= FWCTL_RPC_CONFIGURATION;
+
+	case HWRM_VER_GET:
+	case HWRM_ERROR_RECOVERY_QCFG:
+	case HWRM_FUNC_QCAPS:
+	case HWRM_FUNC_QCFG:
+	case HWRM_FUNC_QSTATS:
+	case HWRM_PORT_PHY_QCFG:
+	case HWRM_PORT_MAC_QCFG:
+	case HWRM_PORT_PHY_QCAPS:
+	case HWRM_PORT_PHY_I2C_READ:
+	case HWRM_PORT_PHY_MDIO_READ:
+	case HWRM_QUEUE_PRI2COS_QCFG:
+	case HWRM_QUEUE_COS2BW_QCFG:
+	case HWRM_VNIC_RSS_QCFG:
+	case HWRM_QUEUE_GLOBAL_QCFG:
+	case HWRM_QUEUE_ADPTV_QOS_RX_FEATURE_QCFG:
+	case HWRM_QUEUE_ADPTV_QOS_TX_FEATURE_QCFG:
+	case HWRM_QUEUE_QCAPS:
+	case HWRM_QUEUE_ADPTV_QOS_RX_TUNING_QCFG:
+	case HWRM_QUEUE_ADPTV_QOS_TX_TUNING_QCFG:
+	case HWRM_TUNNEL_DST_PORT_QUERY:
+	case HWRM_PORT_TX_FIR_QCFG:
+	case HWRM_FW_LIVEPATCH_QUERY:
+	case HWRM_FW_QSTATUS:
+	case HWRM_FW_HEALTH_CHECK:
+	case HWRM_FW_GET_TIME:
+	case HWRM_PORT_EP_TX_QCFG:
+	case HWRM_PORT_QCFG:
+	case HWRM_PORT_MAC_QCAPS:
+	case HWRM_TEMP_MONITOR_QUERY:
+	case HWRM_REG_POWER_QUERY:
+	case HWRM_CORE_FREQUENCY_QUERY:
+	case HWRM_CFA_REDIRECT_QUERY_TUNNEL_TYPE:
+	case HWRM_CFA_ADV_FLOW_MGNT_QCAPS:
+	case HWRM_FUNC_RESOURCE_QCAPS:
+	case HWRM_FUNC_BACKING_STORE_QCAPS:
+	case HWRM_FUNC_BACKING_STORE_QCFG:
+	case HWRM_FUNC_QSTATS_EXT:
+	case HWRM_FUNC_PTP_PIN_QCFG:
+	case HWRM_FUNC_PTP_EXT_QCFG:
+	case HWRM_FUNC_BACKING_STORE_QCFG_V2:
+	case HWRM_FUNC_BACKING_STORE_QCAPS_V2:
+	case HWRM_FUNC_SYNCE_QCFG:
+	case HWRM_FUNC_TTX_PACING_RATE_PROF_QUERY:
+	case HWRM_PORT_PHY_FDRSTAT:
+	case HWRM_DBG_RING_INFO_GET:
+	case HWRM_DBG_QCAPS:
+	case HWRM_DBG_QCFG:
+	case HWRM_DBG_USEQ_FLUSH:
+	case HWRM_DBG_USEQ_QCAPS:
+	case HWRM_DBG_SIM_CABLE_STATE:
+	case HWRM_DBG_TOKEN_QUERY_AUTH_IDS:
+	case HWRM_NVM_GET_DEV_INFO:
+	case HWRM_NVM_GET_DIR_INFO:
+	case HWRM_SELFTEST_QLIST:
+		return scope >= FWCTL_RPC_DEBUG_READ_ONLY;
+
+	case HWRM_PORT_PHY_I2C_WRITE:
+	case HWRM_PORT_PHY_MDIO_WRITE:
+		return scope >= FWCTL_RPC_DEBUG_WRITE;
+
+	default:
+		return false;
+	}
+}
+
+#define BNXTCTL_HWRM_CMD_TIMEOUT_DFLT	500	/* ms */
+#define BNXTCTL_HWRM_CMD_TIMEOUT_MEDM	2000	/* ms */
+#define BNXTCTL_HWRM_CMD_TIMEOUT_LONG	60000	/* ms */
+
+static unsigned int bnxtctl_get_timeout(struct input *req)
+{
+	switch (le16_to_cpu(req->req_type)) {
+	case HWRM_NVM_DEFRAG:
+	case HWRM_NVM_FACTORY_DEFAULTS:
+	case HWRM_NVM_FLUSH:
+	case HWRM_NVM_VERIFY_UPDATE:
+	case HWRM_NVM_ERASE_DIR_ENTRY:
+	case HWRM_NVM_MOD_DIR_ENTRY:
+		return BNXTCTL_HWRM_CMD_TIMEOUT_LONG;
+	case HWRM_FUNC_RESET:
+		return BNXTCTL_HWRM_CMD_TIMEOUT_MEDM;
+	default:
+		return BNXTCTL_HWRM_CMD_TIMEOUT_DFLT;
+	}
+}
+
+static void *bnxtctl_fw_rpc(struct fwctl_uctx *uctx,
+			    enum fwctl_rpc_scope scope,
+			    void *in, size_t in_len, size_t *out_len)
+{
+	struct bnxtctl_dev *bnxtctl =
+		container_of(uctx->fwctl, struct bnxtctl_dev, fwctl);
+	struct bnxt_en_dev *edev = bnxtctl->aux_priv->edev;
+	struct bnxt_fw_msg rpc_in = {0};
+	int rc;
+
+	if (in_len < sizeof(struct input) || in_len > HWRM_MAX_REQ_LEN)
+		return ERR_PTR(-EINVAL);
+
+	if (*out_len < sizeof(struct output))
+		return ERR_PTR(-EINVAL);
+
+	rpc_in.msg = in;
+	rpc_in.msg_len = in_len;
+	rpc_in.resp = kzalloc(*out_len, GFP_KERNEL);
+	if (!rpc_in.resp)
+		return ERR_PTR(-ENOMEM);
+
+	rpc_in.resp_max_len = *out_len;
+	rpc_in.timeout = bnxtctl_get_timeout(in);
+
+	guard(mutex)(&edev->en_dev_lock);
+
+	if (!bnxtctl_validate_rpc(edev, &rpc_in, scope)) {
+		kfree(rpc_in.resp);
+		return ERR_PTR(-EPERM);
+	}
+
+	rc = bnxt_send_msg(edev, &rpc_in);
+	if (rc) {
+		struct output *resp = rpc_in.resp;
+
+		/* Copy the response to user always, as it contains
+		 * detailed status of the command failure
+		 */
+		if (!resp->error_code)
+			/* bnxt_send_msg() returned much before FW
+			 * received the command.
+			 */
+			resp->error_code = cpu_to_le16(rc);
+	}
+
+	return rpc_in.resp;
+}
+
+static const struct fwctl_ops bnxtctl_ops = {
+	.device_type = FWCTL_DEVICE_TYPE_BNXT,
+	.uctx_size = sizeof(struct bnxtctl_uctx),
+	.open_uctx = bnxtctl_open_uctx,
+	.close_uctx = bnxtctl_close_uctx,
+	.info = bnxtctl_info,
+	.fw_rpc = bnxtctl_fw_rpc,
+};
+
+static int bnxtctl_probe(struct auxiliary_device *adev,
+			 const struct auxiliary_device_id *id)
+{
+	struct bnxt_aux_priv *aux_priv =
+		container_of(adev, struct bnxt_aux_priv, aux_dev);
+	struct bnxtctl_dev *bnxtctl __free(bnxtctl) =
+		fwctl_alloc_device(&aux_priv->edev->pdev->dev, &bnxtctl_ops,
+				   struct bnxtctl_dev, fwctl);
+	int rc;
+
+	if (!bnxtctl)
+		return -ENOMEM;
+
+	bnxtctl->aux_priv = aux_priv;
+
+	rc = fwctl_register(&bnxtctl->fwctl);
+	if (rc)
+		return rc;
+
+	auxiliary_set_drvdata(adev, no_free_ptr(bnxtctl));
+	return 0;
+}
+
+static void bnxtctl_remove(struct auxiliary_device *adev)
+{
+	struct bnxtctl_dev *ctldev = auxiliary_get_drvdata(adev);
+
+	fwctl_unregister(&ctldev->fwctl);
+	fwctl_put(&ctldev->fwctl);
+}
+
+static const struct auxiliary_device_id bnxtctl_id_table[] = {
+	{ .name = "bnxt_en.fwctl", },
+	{}
+};
+MODULE_DEVICE_TABLE(auxiliary, bnxtctl_id_table);
+
+static struct auxiliary_driver bnxtctl_driver = {
+	.name = "bnxt_fwctl",
+	.probe = bnxtctl_probe,
+	.remove = bnxtctl_remove,
+	.id_table = bnxtctl_id_table,
+};
+
+module_auxiliary_driver(bnxtctl_driver);
+
+MODULE_IMPORT_NS("FWCTL");
+MODULE_DESCRIPTION("BNXT fwctl driver");
+MODULE_AUTHOR("Pavan Chebbi <pavan.chebbi@broadcom.com>");
+MODULE_AUTHOR("Andy Gospodarek <gospo@broadcom.com>");
+MODULE_LICENSE("GPL");