Hello Wolfgang,
sorry for the delay, I had to clean some other things on my ToDoList.
I cleaned up my patchseries and wanted to start implementing your
proposal. And ran into a problem. Remember, the basic reason for the the
generic FPGA accessors was, that we have a certain amount of basically
identical FPGAs which are only connected to the CPU in different ways.
The drivers accessing those FPGAs should be agnostic of that and simply
be able to access those FPGAs by index.
It appears you need both the element address and the offset in your
fpga_set_reg() code, so you should pass this information, like that
[note that we no longer need an array of addresses]:
struct ihs_fpga fpga_ptr = (struct ihs_fpga *)CONFIG_SYS_FPGA_BASE;
...
void fpga_set_reg(u32 fpga, u16 *reg, off_t regoff, u16 data)
{
if (fpga)
return mclink_send(fpga - 1, regoff, data);
return out_le16(reg, data);
}
where mclink_send() is the routine to access the non memory mapped
FPGAs through the memory mapped FPGA:
int mclink_send(u8 slave, u16 addr, u16 data)
{
...
fpga_set_reg(0, &system_fpgas[0].mc_tx_address, addr);
fpga_set_reg(0, &system_fpgas[0].mc_tx_data, data);
fpga_set_reg(0, &system_fpgas[0].mc_tx_cmd, (slave & 0x03) << 14);
}
And this becomes:
fpga_set_reg(0,
&fpga_ptr->mc_tx_address,
offsetof(struct ihs_fpga, mc_tx_address),
addr);
etc. Yes, this is long and ugly to write, so you may want to define a
helper macro like:
#define FPGA_SET_REG(ix,fld,val) \
fpga_set_reg((ix), \
&fpga_ptr->fld, \
offsetof(struct ihs_fpga, fld), \
val)
so this turns into a plain and simple
FPGA_SET_REG(0, mc_tx_address, addr);
FPGA_SET_REG(0, mc_tx_data, data);
FPGA_SET_REG(0, mc_tx_cmd, (slave & 0x03) << 14);
This works nicely for our memory mapped FPGA. But how about the other
FPGAs? I don't have a fpga_ptr for them. Setting it NULL would make
FPGA_SET_REG dereference a NULL pointer.
Certainly I might call
fpga_set_reg(1,
NULL,
offsetof(struct ihs_fpga, mc_tx_address),
addr);
but that would not be generic any more.
Do you have any idea how to solve this?
Cheers
Dirk
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