On Sun, Feb 16, 2020 at 06:21:09PM +0100, Noralf Trønnes wrote:
Add support for regmap over USB for use with the Multifunction USB Device. Two endpoints IN/OUT are used. Up to 255 regmaps are supported on one USB interface. The register index width is always 32-bit, but the register value can be 8, 16 or 32 bits wide. LZ4 compression is supported on bulk transfers.
This looks like a custom thing for some particular devices rather than a thing that will work for any USB device? If that is the case then this should have a more specific name.
+++ b/drivers/base/regmap/regmap-usb.c @@ -0,0 +1,1026 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/*
- Register map access API - USB support
Why is this GPL-2.0-or-later? The rest of the code is just plain old GPL-2.0.
Please also make the entire comment a C++ one so things look more intentional.
- ktime_t start; /* FIXME: Temporary debug/perf aid */
Add tracepoints, most of your debugging stuff looks like you want to use tracepoints - you can easily work out time differences with them by postprocessing the log, they get very fine grained timestamps.
- mutex_lock(®map_usb_interfaces_lock);
- list_for_each_entry(entry, ®map_usb_interfaces, link)
if (entry->interface == interface) {
ruif = entry;
ruif->refcount++;
goto out_unlock;
}
You're missing some { } here.
+static long mud_drm_throughput(ktime_t begin, ktime_t end, size_t len) +{
- long throughput;
- throughput = ktime_us_delta(end, begin);
- throughput = throughput ? (len * 1000) / throughput : 0;
- throughput = throughput * 1000 / 1024;
Please write normal conditional statements to improve legibility.
+static int regmap_usb_gather_write(void *context,
const void *reg, size_t reg_len,
const void *val, size_t val_len)
+{
- return regmap_usb_transfer(context, false, reg, (void *)val, val_len);
+}
Why are we casting away a const here? If we really need to modify the raw data that's being transmitted take a copy.
+static int regmap_usb_write(void *context, const void *data, size_t count) +{
- struct regmap_usb_context *ctx = context;
- size_t val_len = count - sizeof(u32);
- void *val;
- int ret;
- /* buffer needs to be properly aligned for DMA use */
- val = kmemdup(data + sizeof(u32), val_len, GFP_KERNEL);
- if (!val)
return -ENOMEM;
- ret = regmap_usb_gather_write(ctx, data, sizeof(u32), val, val_len);
- kfree(val);
- return ret;
+}
This looks like you just don't support a straight write operation, if you need to do this emulation push it up the stack.
regmap_usb_debugfs_init(map);
- return map;
+} +EXPORT_SYMBOL(__devm_regmap_init_usb);
No, this needs to be EXPORT_SYMBOL_GPL - the regmap core is and this isn't going to be useful without those bits of the code anyway.