Initial ROCm-docs (#92)

* Initial ROCm-docs commit

Co-authored-by: Aurélien Bouteiller <bouteill@icl.utk.edu>
Co-authored-by: Alex Xu <alex.xu@amd.com>
Co-authored-by: yugang-amd <yugang.wang@amd.com>

docs/api/init.rst

@@ -0,0 +1,98 @@
+.. meta::
+  :description: rocSHMEM intra-kernel networking runtime for AMD dGPUs on the ROCm platform.
+  :keywords: rocSHMEM, API, ROCm, documentation, HIP, Networking, Communication
+
+.. _rocshmem-api-init:
+
+---------------------------------------
+Library Setup, Exit, and Query Routines
+---------------------------------------
+
+ROCSHMEM_INIT
+-------------
+
+.. cpp:function:: __host__ void rocshmem_init(void)
+
+  :Parameters: None
+  :returns: None
+
+**Description:**
+This routine initializes the rocSHMEM runtime and underlying transport layer.
+Before ``rocshmem_init`` is called,
+a user must select the device that this PE is associated to by calling
+`hipSetDevice
+<https://rocm.docs.amd.com/projects/HIP/en/docs-6.0.0/doxygen/html/group___device.html#ga43c1e7f15925eeb762195ccb5e063eae>`_.
+
+.. cpp:function:: __device__ void rocshmem_wg_init(void)
+
+  :Parameters: None
+  :returns: None
+
+**Description:**
+Initializes device-side rocSHMEM resources.
+Must be called before any threads in this work-group invoke other rocSHMEM functions.
+Must be called collectively by all threads in the work-group.
+
+ROCSHMEM_FINALIZE
+-----------------
+.. cpp:function:: __host__ void rocshmem_finalize(void)
+
+  :Parameters: None
+  :returns: None
+
+**Description:**
+Finalize the rocSHMEM runtime.
+
+.. cpp:function:: __device__ void rocshmem_wg_finalize(void)
+
+  :Parameters: None
+  :returns: None
+
+**Description:**
+Finalizes device-side rocSHMEM resources.
+Must be called before work-group completion if the work-group also called ``rocshmem_wg_init``.
+Must be called collectively by all threads in the work-group.
+
+ROCSHMEM_N_PES
+--------------
+
+.. cpp:function:: __host__ int rocshmem_n_pes(void)
+
+  :Parameters: None
+  :returns: Total number of PEs
+
+**Description:**
+Query the total number of PEs.
+This routine can be called before ``rocshmem_init``.
+
+.. cpp:function:: __device__ int rocshmem_n_pes(void)
+.. cpp:function:: __device__ int rocshmem_ctx_n_pes(rocshmem_ctx_t ctx)
+
+  :param ctx: GPU side context handle
+  :returns: Total number of PEs
+
+**Description:**
+Query the total number of PEs for a given context.
+Can be called per thread with no performance penalty.
+
+ROCSHMEM_MY_PE
+--------------
+
+.. cpp:function:: __host__ int rocshmem_my_pe(void)
+
+  :Parameters: None
+  :returns: PE ID of the caller
+
+**Description:**
+Query the PE ID of the caller.
+This routine can be called before ``rocshmem_init``.
+
+.. cpp:function:: __device__ int rocshmem_my_pe(void)
+.. cpp:function:: __device__ int rocshmem_ctx_my_pe(rocshmem_ctx_t ctx)
+
+  :param ctx: GPU side context handle
+  :returns: PE ID of the caller
+
+**Description:**
+Query the PE ID of the caller.
+Can be called per thread with no performance penalty.