2 files changed, 88 insertions, 0 deletions

diff --git a/arch/arc/plat-arcfpga/Kconfig b/arch/arc/plat-arcfpga/Kconfig
index 38752bfb91e0..9912d9c107a0 100644
--- a/arch/arc/plat-arcfpga/Kconfig
+++ b/arch/arc/plat-arcfpga/Kconfig
@@ -44,4 +44,36 @@ config ARC_SERIAL_BAUD
         help
           Baud rate for the ARC UART
 
+menuconfig ARC_HAS_BVCI_LAT_UNIT
+        bool "BVCI Bus Latency Unit"
+        depends on ARC_BOARD_ML509 || ARC_BOARD_ANGEL4
+        help
+          IP to add artifical latency to BVCI Bus Based FPGA builds.
+          The default latency (even worst case) for FPGA is non-realistic
+          (~10 SDRAM, ~5 SSRAM).
+
+config BVCI_LAT_UNITS
+        hex "Latency Unit(s) Bitmap"
+        default "0x0"
+        depends on ARC_HAS_BVCI_LAT_UNIT
+        help
+          There are multiple Latency Units corresponding to the many
+          interfaces of the system bus arbiter (both CPU side as well as
+          the peripheral side).
+          To add latency to ALL memory transaction, choose Unit 0, otherwise
+          for finer grainer - interface wise latency, specify a bitmap (1 bit
+          per unit) of all units. e.g. 1,2,12 will be 0x1003
+
+          Unit  0 - System Arb and Mem Controller
+          Unit  1 - I$ and System Bus
+          Unit  2 - D$ and System Bus
+          ..
+          Unit 12 - IDE Disk controller and System Bus
+
+config BVCI_LAT_CYCLES
+        int "Latency Value in cycles"
+        range 0 63
+        default "30"
+        depends on ARC_HAS_BVCI_LAT_UNIT
+
 endif
diff --git a/arch/arc/plat-arcfpga/platform.c b/arch/arc/plat-arcfpga/platform.c
index 33bcac8bd6b8..b7f63e3f3cae 100644
--- a/arch/arc/plat-arcfpga/platform.c
+++ b/arch/arc/plat-arcfpga/platform.c
@@ -12,6 +12,7 @@
 #include <linux/init.h>
 #include <linux/device.h>
 #include <linux/platform_device.h>
+#include <linux/io.h>
 #include <linux/console.h>
 #include <linux/of_platform.h>
 #include <asm/setup.h>
@@ -19,6 +20,59 @@
 #include <asm/clk.h>
 #include <plat/memmap.h>
 
+/*-----------------------BVCI Latency Unit -----------------------------*/
+
+#ifdef CONFIG_ARC_HAS_BVCI_LAT_UNIT
+
+int lat_cycles = CONFIG_BVCI_LAT_CYCLES;
+
+/* BVCI Bus Profiler: Latency Unit */
+static void __init setup_bvci_lat_unit(void)
+{
+#define MAX_BVCI_UNITS 12
+
+        unsigned int i;
+        unsigned int *base = (unsigned int *)BVCI_LAT_UNIT_BASE;
+        const unsigned long units_req = CONFIG_BVCI_LAT_UNITS;
+        const unsigned int REG_UNIT = 21;
+        const unsigned int REG_VAL = 22;
+
+        /*
+         * There are multiple Latency Units corresponding to the many
+         * interfaces of the system bus arbiter (both CPU side as well as
+         * the peripheral side).
+         *
+         * Unit  0 - System Arb and Mem Controller - adds latency to all
+         *          memory trasactions
+         * Unit  1 - I$ and System Bus
+         * Unit  2 - D$ and System Bus
+         * ..
+         * Unit 12 - IDE Disk controller and System Bus
+         *
+         * The programmers model requires writing to lat_unit reg first
+         * and then the latency value (cycles) to lat_value reg
+         */
+
+        if (CONFIG_BVCI_LAT_UNITS == 0) {
+                writel(0, base + REG_UNIT);
+                writel(lat_cycles, base + REG_VAL);
+                pr_info("BVCI Latency for all Memory Transactions %d cycles\n",
+                        lat_cycles);
+        } else {
+                for_each_set_bit(i, &units_req, MAX_BVCI_UNITS) {
+                        writel(i + 1, base + REG_UNIT); /* loop is 0 based */
+                        writel(lat_cycles, base + REG_VAL);
+                        pr_info("BVCI Latency for Unit[%d] = %d cycles\n",
+                                (i + 1), lat_cycles);
+                }
+        }
+}
+#else
+static void __init setup_bvci_lat_unit(void)
+{
+}
+#endif
+
 /*----------------------- Platform Devices -----------------------------*/
 
 static unsigned long arc_uart_info[] = {
@@ -106,6 +160,8 @@ void __init arc_platform_early_init(void)
 {
         pr_info("[plat-arcfpga]: registering early dev resources\n");
 
+        setup_bvci_lat_unit();
+
         arc_fpga_serial_init();
 }