ARC: [plat-arfpga] BVCI Latency Unit setup

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

diff --git a/arch/arc/plat-arcfpga/Kconfig b/arch/arc/plat-arcfpga/Kconfig
index 38752bf..9912d9c 100644 (file)
--- 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 33bcac8..b7f63e3 100644 (file)
--- 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();
 }