From a0549f7390d33ec522de3a53e6031189d46a9ce7 Mon Sep 17 00:00:00 2001 From: Robert Hancock Date: Tue, 18 Jun 2019 09:47:15 -0600 Subject: [PATCH] fpga: virtex2: Add additional clock cycles after DONE assertion Some Xilinx FPGA configuration options can result in the startup sequence extending past the end of the FPGA bitstream. Continue applying CCLK clock cycles for 8 cycles after DONE is asserted in order to ensure the startup sequence is complete, as recommended by Xilinx. Signed-off-by: Robert Hancock Signed-off-by: Michal Simek --- drivers/fpga/virtex2.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/drivers/fpga/virtex2.c b/drivers/fpga/virtex2.c index 2383c69210..502824424c 100644 --- a/drivers/fpga/virtex2.c +++ b/drivers/fpga/virtex2.c @@ -247,6 +247,7 @@ static int virtex2_slave_post(xilinx_virtex2_slave_selectmap_fns *fn, int cookie) { int ret_val = FPGA_SUCCESS; + int num_done = 0; unsigned long ts; /* @@ -264,12 +265,18 @@ static int virtex2_slave_post(xilinx_virtex2_slave_selectmap_fns *fn, /* * Check for successful configuration. FPGA INIT_B and DONE - * should both be high upon successful configuration. + * should both be high upon successful configuration. Continue pulsing + * clock with data set to all ones until DONE is asserted and for 8 + * clock cycles afterwards. */ ts = get_timer(0); - ret_val = FPGA_SUCCESS; - while (((*fn->done)(cookie) == FPGA_FAIL) || - (*fn->init)(cookie)) { + while (true) { + if ((*fn->done)(cookie) == FPGA_SUCCESS && + !((*fn->init)(cookie))) { + if (num_done++ >= 8) + break; + } + if (get_timer(ts) > CONFIG_SYS_FPGA_WAIT_CONFIG) { printf("%s:%d: ** Timeout after %d ticks waiting for DONE to assert and INIT to deassert\n", __func__, __LINE__, CONFIG_SYS_FPGA_WAIT_CONFIG); @@ -277,6 +284,11 @@ static int virtex2_slave_post(xilinx_virtex2_slave_selectmap_fns *fn, ret_val = FPGA_FAIL; break; } + (*fn->wdata) (0xff, true, cookie); + CONFIG_FPGA_DELAY(); + (*fn->clk) (false, true, cookie); + CONFIG_FPGA_DELAY(); + (*fn->clk) (true, true, cookie); } if (ret_val == FPGA_SUCCESS) { -- 2.39.5