arm: socfpga: Add command to control HPS-FPGA bridges

Add command to enable and disable the bridges between HPS and FPGA.

This patch does have a checkpatch issue with the assembler portion,
checkpatch correctly complains that there should be no whitespace
before quoted newline. I do not agree that fixing this specific
checkpatch issue will improve the readability, thus this one is not
addressed.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Dinh Nguyen <dinguyen@altera.com>
Cc: Pavel Machek <pavel@denx.de>
Cc: Marek Vasut <marex@denx.de>
Cc: Tom Rini <trini@ti.com>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Wolfgang Denk <wd@denx.de>

diff --git a/arch/arm/cpu/armv7/socfpga/misc.c b/arch/arm/cpu/armv7/socfpga/misc.c
index 7f9d7f01337d219310a049d9e5e925aa7dcbc5b5..0eab264668c8502b775b219fffea48797a9f7447 100644 (file)
--- a/arch/arm/cpu/armv7/socfpga/misc.c
+++ b/arch/arm/cpu/armv7/socfpga/misc.c
@@ -22,6 +22,8 @@ static struct pl310_regs *const pl310 =
        (struct pl310_regs *)CONFIG_SYS_PL310_BASE;
 static struct socfpga_system_manager *sysmgr_regs =
        (struct socfpga_system_manager *)SOCFPGA_SYSMGR_ADDRESS;
+static struct socfpga_reset_manager *reset_manager_base =
+       (struct socfpga_reset_manager *)SOCFPGA_RSTMGR_ADDRESS;
 static struct nic301_registers *nic301_regs =
        (struct nic301_registers *)SOCFPGA_L3REGS_ADDRESS;
 static struct scu_registers *scu_regs =
@@ -172,8 +174,14 @@ static void socfpga_nic301_slave_ns(void)
        writel(0x1, &nic301_regs->sdrdata);
 }
 
+static uint32_t iswgrp_handoff[8];
+
 int misc_init_r(void)
 {
+       int i;
+       for (i = 0; i < 8; i++) /* Cache initial SW setting regs */
+               iswgrp_handoff[i] = readl(&sysmgr_regs->iswgrp_handoff[i]);
+
        socfpga_bridges_reset(1);
        socfpga_nic301_slave_ns();
 
@@ -196,3 +204,70 @@ int misc_init_r(void)
        socfpga_fpga_add();
        return 0;
 }
+
+static void socfpga_sdram_apply_static_cfg(void)
+{
+       const uint32_t staticcfg = SOCFPGA_SDR_ADDRESS + 0x505c;
+       const uint32_t applymask = 0x8;
+       uint32_t val = readl(staticcfg) | applymask;
+
+       /*
+        * SDRAM staticcfg register specific:
+        * When applying the register setting, the CPU must not access
+        * SDRAM. Luckily for us, we can abuse i-cache here to help us
+        * circumvent the SDRAM access issue. The idea is to make sure
+        * that the code is in one full i-cache line by branching past
+        * it and back. Once it is in the i-cache, we execute the core
+        * of the code and apply the register settings.
+        *
+        * The code below uses 7 instructions, while the Cortex-A9 has
+        * 32-byte cachelines, thus the limit is 8 instructions total.
+        */
+       asm volatile(
+               ".align 5                       \n"
+               "       b       2f              \n"
+               "1:     str     %0,     [%1]    \n"
+               "       dsb                     \n"
+               "       isb                     \n"
+               "       b       3f              \n"
+               "2:     b       1b              \n"
+               "3:     nop                     \n"
+       : : "r"(val), "r"(staticcfg) : "memory", "cc");
+}
+
+int do_bridge(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+       if (argc != 2)
+               return CMD_RET_USAGE;
+
+       argv++;
+
+       switch (*argv[0]) {
+       case 'e':       /* Enable */
+               writel(iswgrp_handoff[2], &sysmgr_regs->fpgaintfgrp_module);
+               socfpga_sdram_apply_static_cfg();
+               writel(iswgrp_handoff[3], SOCFPGA_SDR_ADDRESS + 0x5080);
+               writel(iswgrp_handoff[0], &reset_manager_base->brg_mod_reset);
+               writel(iswgrp_handoff[1], &nic301_regs->remap);
+               break;
+       case 'd':       /* Disable */
+               writel(0, &sysmgr_regs->fpgaintfgrp_module);
+               writel(0, SOCFPGA_SDR_ADDRESS + 0x5080);
+               socfpga_sdram_apply_static_cfg();
+               writel(0, &reset_manager_base->brg_mod_reset);
+               writel(1, &nic301_regs->remap);
+               break;
+       default:
+               return CMD_RET_USAGE;
+       }
+
+       return 0;
+}
+
+U_BOOT_CMD(
+       bridge, 2, 1, do_bridge,
+       "SoCFPGA HPS FPGA bridge control",
+       "enable  - Enable HPS-to-FPGA, FPGA-to-HPS, LWHPS-to-FPGA bridges\n"
+       "bridge disable - Enable HPS-to-FPGA, FPGA-to-HPS, LWHPS-to-FPGA bridges\n"
+       ""
+);