remoteproc: xlnx: Add attach detach support

It is possible that remote processor is already running before
linux boot or remoteproc platform driver probe. Implement required
remoteproc framework ops to provide resource table address and
connect or disconnect with remote processor in such case.

Signed-off-by: Tanmay Shah <tanmay.shah@amd.com>
Link: https://lore.kernel.org/r/20240627172936.227439-1-tanmay.shah@amd.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

Author: tnmysh

drivers/remoteproc/xlnx_r5_remoteproc.c

@@ -25,6 +25,10 @@
 /* RX mailbox client buffer max length */
 #define MBOX_CLIENT_BUF_MAX	(IPI_BUF_LEN_MAX + \
 				 sizeof(struct zynqmp_ipi_message))
+
+#define RSC_TBL_XLNX_MAGIC	((uint32_t)'x' << 24 | (uint32_t)'a' << 16 | \
+				 (uint32_t)'m' << 8 | (uint32_t)'p')
+
 /*
  * settings for RPU cluster mode which
  * reflects possible values of xlnx,cluster-mode dt-property
@@ -73,6 +77,26 @@ struct mbox_info {
 	struct mbox_chan *rx_chan;
 };
 
+/**
+ * struct rsc_tbl_data
+ *
+ * Platform specific data structure used to sync resource table address.
+ * It's important to maintain order and size of each field on remote side.
+ *
+ * @version: version of data structure
+ * @magic_num: 32-bit magic number.
+ * @comp_magic_num: complement of above magic number
+ * @rsc_tbl_size: resource table size
+ * @rsc_tbl: resource table address
+ */
+struct rsc_tbl_data {
+	const int version;
+	const u32 magic_num;
+	const u32 comp_magic_num;
+	const u32 rsc_tbl_size;
+	const uintptr_t rsc_tbl;
+} __packed;
+
 /*
  * Hardcoded TCM bank values. This will stay in driver to maintain backward
  * compatibility with device-tree that does not have TCM information.
@@ -95,20 +119,24 @@ static const struct mem_bank_data zynqmp_tcm_banks_lockstep[] = {
 /**
  * struct zynqmp_r5_core
  *
+ * @rsc_tbl_va: resource table virtual address
  * @dev: device of RPU instance
  * @np: device node of RPU instance
  * @tcm_bank_count: number TCM banks accessible to this RPU
  * @tcm_banks: array of each TCM bank data
  * @rproc: rproc handle
+ * @rsc_tbl_size: resource table size retrieved from remote
  * @pm_domain_id: RPU CPU power domain id
  * @ipi: pointer to mailbox information
  */
 struct zynqmp_r5_core {
+	void __iomem *rsc_tbl_va;
 	struct device *dev;
 	struct device_node *np;
 	int tcm_bank_count;
 	struct mem_bank_data **tcm_banks;
 	struct rproc *rproc;
+	u32 rsc_tbl_size;
 	u32 pm_domain_id;
 	struct mbox_info *ipi;
 };
@@ -557,6 +585,14 @@ static int add_tcm_banks(struct rproc *rproc)
 		dev_dbg(dev, "TCM carveout %s addr=%llx, da=0x%x, size=0x%lx",
 			bank_name, bank_addr, da, bank_size);
 
+		/*
+		 * In DETACHED state firmware is already running so no need to
+		 * request add TCM registers. However, request TCM PD node to let
+		 * platform management firmware know that TCM is in use.
+		 */
+		if (rproc->state == RPROC_DETACHED)
+			continue;
+
 		rproc_mem = rproc_mem_entry_init(dev, NULL, bank_addr,
 						 bank_size, da,
 						 tcm_mem_map, tcm_mem_unmap,
@@ -662,6 +698,107 @@ static int zynqmp_r5_rproc_unprepare(struct rproc *rproc)
 	return 0;
 }
 
+static struct resource_table *zynqmp_r5_get_loaded_rsc_table(struct rproc *rproc,
+							     size_t *size)
+{
+	struct zynqmp_r5_core *r5_core;
+
+	r5_core = rproc->priv;
+
+	*size = r5_core->rsc_tbl_size;
+
+	return (struct resource_table *)r5_core->rsc_tbl_va;
+}
+
+static int zynqmp_r5_get_rsc_table_va(struct zynqmp_r5_core *r5_core)
+{
+	struct resource_table *rsc_tbl_addr;
+	struct device *dev = r5_core->dev;
+	struct rsc_tbl_data *rsc_data_va;
+	struct resource res_mem;
+	struct device_node *np;
+	int ret;
+
+	/*
+	 * It is expected from remote processor firmware to provide resource
+	 * table address via struct rsc_tbl_data data structure.
+	 * Start address of first entry under "memory-region" property list
+	 * contains that data structure which holds resource table address, size
+	 * and some magic number to validate correct resource table entry.
+	 */
+	np = of_parse_phandle(r5_core->np, "memory-region", 0);
+	if (!np) {
+		dev_err(dev, "failed to get memory region dev node\n");
+		return -EINVAL;
+	}
+
+	ret = of_address_to_resource(np, 0, &res_mem);
+	of_node_put(np);
+	if (ret) {
+		dev_err(dev, "failed to get memory-region resource addr\n");
+		return -EINVAL;
+	}
+
+	rsc_data_va = (struct rsc_tbl_data *)ioremap_wc(res_mem.start,
+							sizeof(struct rsc_tbl_data));
+	if (!rsc_data_va) {
+		dev_err(dev, "failed to map resource table data address\n");
+		return -EIO;
+	}
+
+	/*
+	 * If RSC_TBL_XLNX_MAGIC number and its complement isn't found then
+	 * do not consider resource table address valid and don't attach
+	 */
+	if (rsc_data_va->magic_num != RSC_TBL_XLNX_MAGIC ||
+	    rsc_data_va->comp_magic_num != ~RSC_TBL_XLNX_MAGIC) {
+		dev_dbg(dev, "invalid magic number, won't attach\n");
+		return -EINVAL;
+	}
+
+	r5_core->rsc_tbl_va = ioremap_wc(rsc_data_va->rsc_tbl,
+					 rsc_data_va->rsc_tbl_size);
+	if (!r5_core->rsc_tbl_va) {
+		dev_err(dev, "failed to get resource table va\n");
+		return -EINVAL;
+	}
+
+	rsc_tbl_addr = (struct resource_table *)r5_core->rsc_tbl_va;
+
+	/*
+	 * As of now resource table version 1 is expected. Don't fail to attach
+	 * but warn users about it.
+	 */
+	if (rsc_tbl_addr->ver != 1)
+		dev_warn(dev, "unexpected resource table version %d\n",
+			 rsc_tbl_addr->ver);
+
+	r5_core->rsc_tbl_size = rsc_data_va->rsc_tbl_size;
+
+	iounmap((void __iomem *)rsc_data_va);
+
+	return 0;
+}
+
+static int zynqmp_r5_attach(struct rproc *rproc)
+{
+	dev_dbg(&rproc->dev, "rproc %d attached\n", rproc->index);
+
+	return 0;
+}
+
+static int zynqmp_r5_detach(struct rproc *rproc)
+{
+	/*
+	 * Generate last notification to remote after clearing virtio flag.
+	 * Remote can avoid polling on virtio reset flag if kick is generated
+	 * during detach by host and check virtio reset flag on kick interrupt.
+	 */
+	zynqmp_r5_rproc_kick(rproc, 0);
+
+	return 0;
+}
+
 static const struct rproc_ops zynqmp_r5_rproc_ops = {
 	.prepare	= zynqmp_r5_rproc_prepare,
 	.unprepare	= zynqmp_r5_rproc_unprepare,
@@ -673,6 +810,9 @@ static const struct rproc_ops zynqmp_r5_rproc_ops = {
 	.sanity_check	= rproc_elf_sanity_check,
 	.get_boot_addr	= rproc_elf_get_boot_addr,
 	.kick		= zynqmp_r5_rproc_kick,
+	.get_loaded_rsc_table = zynqmp_r5_get_loaded_rsc_table,
+	.attach		= zynqmp_r5_attach,
+	.detach		= zynqmp_r5_detach,
 };
 
 /**
@@ -723,6 +863,16 @@ static struct zynqmp_r5_core *zynqmp_r5_add_rproc_core(struct device *cdev)
 		goto free_rproc;
 	}
 
+	/*
+	 * If firmware is already available in the memory then move rproc state
+	 * to DETACHED. Firmware can be preloaded via debugger or by any other
+	 * agent (processors) in the system.
+	 * If firmware isn't available in the memory and resource table isn't
+	 * found, then rproc state remains OFFLINE.
+	 */
+	if (!zynqmp_r5_get_rsc_table_va(r5_core))
+		r5_rproc->state = RPROC_DETACHED;
+
 	r5_core->rproc = r5_rproc;
 	return r5_core;
 
@@ -1134,6 +1284,7 @@ static void zynqmp_r5_cluster_exit(void *data)
 	for (i = 0; i < cluster->core_count; i++) {
 		r5_core = cluster->r5_cores[i];
 		zynqmp_r5_free_mbox(r5_core->ipi);
+		iounmap(r5_core->rsc_tbl_va);
 		of_reserved_mem_device_release(r5_core->dev);
 		put_device(r5_core->dev);
 		rproc_del(r5_core->rproc);