pds_fwctl: initial driver framework

Initial files for adding a new fwctl driver for the AMD/Pensando PDS
devices.  This sets up a simple auxiliary_bus driver that registers
with fwctl subsystem.  It expects that a pds_core device has set up
the auxiliary_device pds_core.fwctl

Link: https://patch.msgid.link/r/20250320194412.67983-5-shannon.nelson@amd.com
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

4 files changed, 183 insertions, 0 deletions

diff --git a/drivers/fwctl/Kconfig b/drivers/fwctl/Kconfig
index f802cf5d4951..b5583b12a011 100644
--- a/drivers/fwctl/Kconfig
+++ b/drivers/fwctl/Kconfig
@@ -20,4 +20,14 @@ config FWCTL_MLX5
 	  mainstream kernel.
 
 	  If you don't know what to do here, say N.
+
+config FWCTL_PDS
+	tristate "AMD/Pensando pds fwctl driver"
+	depends on PDS_CORE
+	help
+	  The pds_fwctl driver provides an fwctl interface for a user process
+	  to access the debug and configuration information of the AMD/Pensando
+	  DSC hardware family.
+
+	  If you don't know what to do here, say N.
 endif
diff --git a/drivers/fwctl/Makefile b/drivers/fwctl/Makefile
index 1c535f694d7f..c093b5f661d6 100644
--- a/drivers/fwctl/Makefile
+++ b/drivers/fwctl/Makefile
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_FWCTL) += fwctl.o
 obj-$(CONFIG_FWCTL_MLX5) += mlx5/
+obj-$(CONFIG_FWCTL_PDS) += pds/
 
 fwctl-y += main.o
diff --git a/drivers/fwctl/pds/Makefile b/drivers/fwctl/pds/Makefile
new file mode 100644
index 000000000000..cc2317c07be1
--- /dev/null
+++ b/drivers/fwctl/pds/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_FWCTL_PDS) += pds_fwctl.o
+
+pds_fwctl-y += main.o
diff --git a/drivers/fwctl/pds/main.c b/drivers/fwctl/pds/main.c
new file mode 100644
index 000000000000..7542a424b788
--- /dev/null
+++ b/drivers/fwctl/pds/main.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) Advanced Micro Devices, Inc */
+
+#include <linux/module.h>
+#include <linux/auxiliary_bus.h>
+#include <linux/pci.h>
+#include <linux/vmalloc.h>
+
+#include <uapi/fwctl/fwctl.h>
+#include <uapi/fwctl/pds.h>
+#include <linux/fwctl.h>
+
+#include <linux/pds/pds_common.h>
+#include <linux/pds/pds_core_if.h>
+#include <linux/pds/pds_adminq.h>
+#include <linux/pds/pds_auxbus.h>
+
+struct pdsfc_uctx {
+	struct fwctl_uctx uctx;
+	u32 uctx_caps;
+};
+
+struct pdsfc_dev {
+	struct fwctl_device fwctl;
+	struct pds_auxiliary_dev *padev;
+	u32 caps;
+	struct pds_fwctl_ident ident;
+};
+
+static int pdsfc_open_uctx(struct fwctl_uctx *uctx)
+{
+	struct pdsfc_dev *pdsfc = container_of(uctx->fwctl, struct pdsfc_dev, fwctl);
+	struct pdsfc_uctx *pdsfc_uctx = container_of(uctx, struct pdsfc_uctx, uctx);
+
+	pdsfc_uctx->uctx_caps = pdsfc->caps;
+
+	return 0;
+}
+
+static void pdsfc_close_uctx(struct fwctl_uctx *uctx)
+{
+}
+
+static void *pdsfc_info(struct fwctl_uctx *uctx, size_t *length)
+{
+	struct pdsfc_uctx *pdsfc_uctx = container_of(uctx, struct pdsfc_uctx, uctx);
+	struct fwctl_info_pds *info;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return ERR_PTR(-ENOMEM);
+
+	info->uctx_caps = pdsfc_uctx->uctx_caps;
+
+	return info;
+}
+
+static int pdsfc_identify(struct pdsfc_dev *pdsfc)
+{
+	struct device *dev = &pdsfc->fwctl.dev;
+	union pds_core_adminq_comp comp = {0};
+	union pds_core_adminq_cmd cmd;
+	struct pds_fwctl_ident *ident;
+	dma_addr_t ident_pa;
+	int err;
+
+	ident = dma_alloc_coherent(dev->parent, sizeof(*ident), &ident_pa, GFP_KERNEL);
+	if (!ident) {
+		dev_err(dev, "Failed to map ident buffer\n");
+		return -ENOMEM;
+	}
+
+	cmd = (union pds_core_adminq_cmd) {
+		.fwctl_ident = {
+			.opcode = PDS_FWCTL_CMD_IDENT,
+			.version = 0,
+			.len = cpu_to_le32(sizeof(*ident)),
+			.ident_pa = cpu_to_le64(ident_pa),
+		}
+	};
+
+	err = pds_client_adminq_cmd(pdsfc->padev, &cmd, sizeof(cmd), &comp, 0);
+	if (err)
+		dev_err(dev, "Failed to send adminq cmd opcode: %u err: %d\n",
+			cmd.fwctl_ident.opcode, err);
+	else
+		pdsfc->ident = *ident;
+
+	dma_free_coherent(dev->parent, sizeof(*ident), ident, ident_pa);
+
+	return err;
+}
+
+static void *pdsfc_fw_rpc(struct fwctl_uctx *uctx, enum fwctl_rpc_scope scope,
+			  void *in, size_t in_len, size_t *out_len)
+{
+	return NULL;
+}
+
+static const struct fwctl_ops pdsfc_ops = {
+	.device_type = FWCTL_DEVICE_TYPE_PDS,
+	.uctx_size = sizeof(struct pdsfc_uctx),
+	.open_uctx = pdsfc_open_uctx,
+	.close_uctx = pdsfc_close_uctx,
+	.info = pdsfc_info,
+	.fw_rpc = pdsfc_fw_rpc,
+};
+
+static int pdsfc_probe(struct auxiliary_device *adev,
+		       const struct auxiliary_device_id *id)
+{
+	struct pds_auxiliary_dev *padev =
+			container_of(adev, struct pds_auxiliary_dev, aux_dev);
+	struct device *dev = &adev->dev;
+	struct pdsfc_dev *pdsfc;
+	int err;
+
+	pdsfc = fwctl_alloc_device(&padev->vf_pdev->dev, &pdsfc_ops,
+				   struct pdsfc_dev, fwctl);
+	if (!pdsfc)
+		return dev_err_probe(dev, -ENOMEM, "Failed to allocate fwctl device struct\n");
+	pdsfc->padev = padev;
+
+	err = pdsfc_identify(pdsfc);
+	if (err) {
+		fwctl_put(&pdsfc->fwctl);
+		return dev_err_probe(dev, err, "Failed to identify device\n");
+	}
+
+	err = fwctl_register(&pdsfc->fwctl);
+	if (err) {
+		fwctl_put(&pdsfc->fwctl);
+		return dev_err_probe(dev, err, "Failed to register device\n");
+	}
+
+	auxiliary_set_drvdata(adev, pdsfc);
+
+	return 0;
+}
+
+static void pdsfc_remove(struct auxiliary_device *adev)
+{
+	struct pdsfc_dev *pdsfc = auxiliary_get_drvdata(adev);
+
+	fwctl_unregister(&pdsfc->fwctl);
+	fwctl_put(&pdsfc->fwctl);
+}
+
+static const struct auxiliary_device_id pdsfc_id_table[] = {
+	{.name = PDS_CORE_DRV_NAME "." PDS_DEV_TYPE_FWCTL_STR },
+	{}
+};
+MODULE_DEVICE_TABLE(auxiliary, pdsfc_id_table);
+
+static struct auxiliary_driver pdsfc_driver = {
+	.name = "pds_fwctl",
+	.probe = pdsfc_probe,
+	.remove = pdsfc_remove,
+	.id_table = pdsfc_id_table,
+};
+
+module_auxiliary_driver(pdsfc_driver);
+
+MODULE_IMPORT_NS("FWCTL");
+MODULE_DESCRIPTION("pds fwctl driver");
+MODULE_AUTHOR("Shannon Nelson <shannon.nelson@amd.com>");
+MODULE_AUTHOR("Brett Creeley <brett.creeley@amd.com>");
+MODULE_LICENSE("GPL");