Hi Paul,
On Wed, Dec 23, 2020 at 10:57:09AM +0000, Paul Cercueil wrote:
> Hi,
>
> Having written the ingenic-remoteproc driver I am trying now to write
> something a bit more advanced than a hello-world. Something like a
> case-invert program for starters. However I'm having a hard time trying to
> figure out how things work.
>
> My resource table is as follows:
>
> ----------------------------
> struct resource_table_hdr {
> struct resource_table header;
>
> uint32_t offset[3];
>
> struct {
> struct fw_rsc_hdr header;
> struct fw_rsc_carveout carveout;
> } carveout;
>
> struct {
> struct fw_rsc_hdr header;
> struct fw_rsc_trace trace;
> } trace;
>
> struct {
> struct fw_rsc_hdr header;
> struct fw_rsc_vdev vdev;
> struct fw_rsc_vdev_vring vrings[2];
> uint8_t config[0xc];
> } vdev;
> };
>
> const struct resource_table_hdr resource_table
> __attribute__((used, section (".resource_table"))) = {
> .header = {
> .ver = 1,
> .num = ARRAY_SIZE(resource_table.offset), /* Number of resources */
> },
>
> .offset[0] = offsetof(struct resource_table_hdr, carveout),
> .offset[1] = offsetof(struct resource_table_hdr, trace),
> .offset[2] = offsetof(struct resource_table_hdr, vdev),
>
> .carveout = {
> .header = {
> .type = RSC_CARVEOUT,
> },
> .carveout = {
> .da = 0xf4000000,
> .len = 0x2000,
> .name = "firmware",
> },
> },
>
> /* Trace resource to printf() into */
> .trace = {
> .header = {
> .type = RSC_TRACE,
> },
> .trace = {
> .da = (uint32_t)trace_buf,
> .len = TRACE_BUFFER_SIZE,
> .name = "trace",
> },
> },
>
> /* VirtIO device */
> .vdev = {
> .header = {
> .type = RSC_VDEV,
> },
> .vdev = {
> .id = VIRTIO_ID_RPROC_SERIAL,
> .notifyid = 0,
> .dfeatures = 0,
> .config_len = 0xc,
> .num_of_vrings = 2,
> },
> .vrings = {
> [0] = {
> .align = 0x10,
> .num = 0x4,
> .notifyid = 0,
> },
> [1] = {
> .align = 0x10,
> .num = 0x4,
> .notifyid = 0,
> },
> },
> },
> };
> ----------------------------
>
The lack of proper tabulation above makes it really hard to read.
> The firmware is properly loaded and I get debug prints in my trace buffer.
> However, my vrings' .da fields don't seem to be initialized to anything
> meaningful at all. Then I use the virtio/vring code from (https://github.com/MIPS/mips-rproc-example/blob/master/firmware/common/include/vring.h),
> and calling vring_print() shows that my vring_desc's addresses are garbage
> as well.
>
> Is there an example on how to write a basic I/O remoteproc program?
>
The easiest is probably to implement a VIRTIO_ID_RPMSG and try to test things
out with the RPMSG client sample application [1]. It isn't an I/O example but it
will allow you to quickly find the problem with the vring addresses.
You may also want to checkout ST's development kit [2] if you want a working
example. I use it as one of my reference board, the price is right and the
support is completely upstream.
Mathieu
[1]. https://elixir.bootlin.com/linux/latest/source/samples/rpmsg/rpmsg_client_sample.c
[2]. https://www.st.com/en/evaluation-tools/stm32mp157c-dk2.html
> Cheers,
> -Paul
>
>
