Hi Thomas, On Mon, Dec 04, 2017 at 01:43:15PM +0000, Thomas Petazzoni wrote: > The current FPGA subsystem only allows programming the FPGA bitstream > through Device Tree overlays. This assumes that the devices inside the > FPGA are described through a Device Tree. > > However, some platforms have their FPGA connected to the main CPU over > PCIe and the devices in the FPGA are therefore dynamically > discoverable using the normal PCIe enumeration mechanisms. There is > therefore no Device Tree overlay describing the devices in the > FPGA. Furthermore, on my platform (an old SH7786), there is no Device > Tree at all, as there is no support for Device Tree for this SoC. > > Adding a userspace interface to trigger the programming of the FPGA > has already been requested in the past (see [1]) showing that there is > a need for such a feature. > > This commit therefore introduces a very simple interface, in the form > of a "load" sysfs file. Writing the name of the firmware file to > program into the FPGA to this "load" file triggers the programming > process. Thank you for your patch. I have used it succesfully to program and reprogram with different bit files an 'invisible' FPGA which is actually a piece of hardware bridging a Sub LVDS CMOS sensor output to a CSI MIPI-2 input. If this patch is not suitable in the general case it could at least be made available for development context. Attached is a small patch on top of yours that fixes a minor annoyance when using 'echo' without the '-n' option. Philippe -- Philippe De Muyter +32 2 6101532 Macq SA rue de l'Aeronef 2 B-1140 Bruxelles
>From 284a904c4f8bf3978735d234c7ee2bacfd10edaf Mon Sep 17 00:00:00 2001 From: Philippe De Muyter <phdm@xxxxxxxxx> Date: Fri, 10 Aug 2018 09:35:41 +0200 Subject: [PATCH] FIX "fpga: add simple userspace interface to trigger FPGA programming" When fpga-mgr load_store strips the received string to remove the terminating '\n', it should still return the whole count, not the stripped one. Signed-off-by: Philippe De Muyter <phdm@xxxxxxxxx> --- drivers/fpga/fpga-mgr.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c index 751a447..61492787 100644 --- a/drivers/fpga/fpga-mgr.c +++ b/drivers/fpga/fpga-mgr.c @@ -404,11 +404,15 @@ static ssize_t load_store(struct device *dev, struct fpga_manager *mgr = to_fpga_manager(dev); char *name; int ret; + size_t stripped_count = count; if (count > 0 && buf[count - 1] == '\n') - count--; + stripped_count--; - name = kstrndup(buf, count, GFP_KERNEL); + if (!stripped_count) + return count; + + name = kstrndup(buf, stripped_count, GFP_KERNEL); if (!name) return -ENOSPC; -- 2.7.4
