video: tsec: Add support to alloc GSC memory

For larger commands that do not fit into the
CMD Queue we pass additional parameters and
buffer by using the GSC. DisplayRM uses the
GSC allocation APIs to reserve memory for
such large command parameters.

Bug 3920791

Change-Id: I7a2a9821d32e1a89726cf3fb53cd5647eccbadd7
Signed-off-by: Nikesh Oswal <noswal@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvidia/+/2834319
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>
Reviewed-by: svcacv <svcacv@nvidia.com>
GVS: Gerrit_Virtual_Submit <buildbot_gerritrpt@nvidia.com>

drivers/video/tegra/tsec/tsec_comms/tsec_comms.c

@@ -2,7 +2,7 @@
 /*
  * Tegra TSEC Module Support
  *
- * Copyright (c) 2022, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2022-2023, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -44,6 +44,7 @@ static u64 s_ipc_gscco_size;
 static u64 s_ipc_gscco_page_base;
 static u64 s_ipc_gscco_page_size;
 static u64 s_ipc_gscco_page_count;
+static u64 s_ipc_gscco_free_page_mask;
 struct TSEC_BOOT_INFO {
 	u32 bootFlag;
 };
@@ -413,6 +414,7 @@ void tsec_comms_initialize(u64 ipc_co_va, u64 ipc_co_va_size)
 	}
 	s_ipc_gscco_page_base = s_ipc_gscco_page_count ?
 		s_ipc_gscco_base + s_ipc_gscco_page_size : 0;
+	s_ipc_gscco_free_page_mask = ~((u64)0);
 #else
 	(void)ipc_co_va;
 	(void)ipc_co_va_size;
@@ -446,6 +448,67 @@ void *tsec_comms_get_gscco_page(u32 page_number, u32 *gscco_offset)
 }
 EXPORT_SYMBOL_COMMS(tsec_comms_get_gscco_page);
 
+void *tsec_comms_alloc_mem_from_gscco(u32 size_in_bytes, u32 *gscco_offset)
+{
+#ifdef DO_IPC_OVER_GSC_CO
+	void *page_va;
+	u32 page_number;
+	u64 mask;
+
+	/* memory allocated must fit within 1 page */
+	if (size_in_bytes > s_ipc_gscco_page_size) {
+		plat_print(LVL_ERR,
+			"%s: size %d is larger than page size\n",
+			__func__, size_in_bytes);
+		return NULL;
+	}
+	/* there must be atleast 1 page free */
+	if (s_ipc_gscco_free_page_mask == 0) {
+		plat_print(LVL_ERR,
+			"%s: No free page\n", __func__);
+		return NULL;
+	}
+
+	/* find a free page */
+	page_number = 0;
+	mask = 0x1;
+	while (!(s_ipc_gscco_free_page_mask & mask)) {
+		mask       <<= 1;
+		page_number += 1;
+	}
+
+	/* allocate page */
+	page_va = tsec_comms_get_gscco_page(page_number, gscco_offset);
+	if (page_va)
+		s_ipc_gscco_free_page_mask &= ~(mask);
+
+	return page_va;
+#else
+	plat_print(LVL_ERR, "%s: IPC over GSC-CO not enabled\n", __func__);
+	return NULL;
+#endif
+}
+EXPORT_SYMBOL_COMMS(tsec_comms_alloc_mem_from_gscco);
+
+void tsec_comms_free_gscco_mem(void *page_va)
+{
+#ifdef DO_IPC_OVER_GSC_CO
+	u64 page_addr = (u64)page_va;
+	u64 gscco_page_start = s_ipc_gscco_page_base;
+	u64 gscco_page_end = s_ipc_gscco_page_base +
+		(s_ipc_gscco_page_count * s_ipc_gscco_page_size);
+	u64 page_number = (page_addr - gscco_page_start) /
+		s_ipc_gscco_page_size;
+
+	if ((page_addr >= gscco_page_start) &&
+	    (page_addr < gscco_page_end) &&
+	    (!(page_addr % s_ipc_gscco_page_size)))
+		s_ipc_gscco_free_page_mask |= ((u64)0x1 << page_number);
+#endif
+}
+EXPORT_SYMBOL_COMMS(tsec_comms_free_gscco_mem);
+
+
 int tsec_comms_send_cmd(void *cmd, u32 queue_id,
 	callback_func_t cb_func, void *cb_ctx)
 {

drivers/video/tegra/tsec/tsec_comms/tsec_comms.h

@@ -2,7 +2,7 @@
 /*
  * Tegra TSEC Module Support
  *
- * Copyright (c) 2022, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2022-2023, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -93,10 +93,32 @@ int tsec_comms_send_cmd(void *cmd, u32 queue_id,
  *
  * params[in]: page_number  page number
  * params[in/out]: gscco_offset filled with offset of the allocated co page
- * params[out]: ccplex va for the co page
+ * params[out]: return value - ccplex va for the co page or NULL if
+ * page_number more than number of available pages
  */
 void *tsec_comms_get_gscco_page(u32 page_number, u32 *gscco_offset);
 
+
+/* @brief: Allocates memory from carveout
+ *
+ * usage: Called to allocate memory from the carveout.
+ *
+ * params[in]: size_in_bytes conveys the required size (must be less
+ * than page size)
+ * params[in/out]: gscco_offset filled with offset of the allocated co memory
+ * params[out]: return value - ccplex va for the co memory or NULL if
+ * allocation failure
+ */
+void *tsec_comms_alloc_mem_from_gscco(u32 size_in_bytes, u32 *gscco_offset);
+
+/* @brief: Free the memory previously allocated using
+ *         tsec_comms_alloc_mem_from_gscco
+ *
+ * params[in]: page_va previously allocated using
+ *             tsec_comms_alloc_mem_from_gscco
+ */
+void tsec_comms_free_gscco_mem(void *page_va);
+
 /* -------- END -------- */
 
 #endif /* TSEC_COMMS_H */