2017-06-30 19:01 GMT+08:00 Leif Lindholm leif.lindholm@linaro.org:
Hi Jun,
I think there is more than one benefit in mimicing the Linux driver, so I would lean towards the Pcd option. But as Ard points out to me, it needs to use a FixedPcd (using FixedPcdGet()) - this can only ever have a buildtime resolution.
Regards,
Leif (technically on holiday, so no patch review until Monday)
Just learn from Liming that a MACRO is OK to control the register offset definition in header file as we can change build option in platform.dsc file. This should be most clear method to minimize impact to other platform.
Jun
On Fri, Jun 30, 2017 at 11:35:26AM +0800, Jun Nie wrote:
Hi,
I am trying to add support to different reg offset and bit offset in PL011 UART. It seems impossible to add macro in platform.dsc to enable undef/redef in the header file with "#ifdef ZX_PL011_FLAG". Is there any proper way to control the reg/bit offset definition? Or we have to adopt the Linux driver method with a structure to hold different offset value and wrap register access function as below? If so, another Pcd is needed to specify the offset structure index for the platforms.
static u16 pl011_st_offsets[REG_ARRAY_SIZE] = { [REG_DR] = UART01x_DR, [REG_ST_DMAWM] = ST_UART011_DMAWM, [REG_ST_TIMEOUT] = ST_UART011_TIMEOUT, ... }
static unsigned int pl011_read(const struct uart_amba_port *uap, unsigned int reg) { void __iomem *addr = uap->port.membase + uap->reg_offset[reg];
return (uap->port.iotype == UPIO_MEM32) ? readl_relaxed(addr) : readw_relaxed(addr); }
Jun