Messages in this thread | | | Date | Thu, 27 Feb 2014 12:04:13 +0530 | From | Kishon Vijay Abraham I <> | Subject | Re: [PATCH RESEND v10 3/4] PHY: add APM X-Gene SoC 15Gbps Multi-purpose PHY driver |
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On Thursday 27 February 2014 11:55 AM, Loc Ho wrote: > Hi, > >>>>> + >>>>> +static void sds_wr(void __iomem *csr_base, u32 indirect_cmd_reg, >>>>> + u32 indirect_data_reg, u32 addr, u32 data) >>>>> +{ >>>>> + u32 val; >>>>> + u32 cmd; >>>>> + >>>>> + cmd = CFG_IND_WR_CMD_MASK | CFG_IND_CMD_DONE_MASK; >>>>> + cmd = CFG_IND_ADDR_SET(cmd, addr); >>>> >>>> >>>> >>>> This looks hacky. If 'CFG_IND_WR_CMD_MASK | CFG_IND_CMD_DONE_MASK' should >>>> be set then it should be part of the second argument. From the macro >>>> 'CFG_IND_ADDR_SET' the first argument should be more like the current value >>>> present in the register right? I feel the macro (CFG_IND_ADDR_SET) is not >>>> used in the way it is intended to. >>> >>> >>> The macro XXX_SET is intended to update an field within the register. >>> The update field is returned. The first assignment lines are setting >>> another field. Those two lines can be written as: >>> >>> cmd = 0; >>> cmd |= CFG_IND_WR_CMD_MASK; ==> Set the CMD bit >>> cmd |= CFG_IND_CMD_DONE_MASK; ==> Set the DONE bit >>> cmd = CFG_IND_ADDR_SET(cmd, addr); ===> Set the field ADDR >> >> >> #define CFG_IND_ADDR_SET(dst, src) \ >> (((dst) & ~0x003ffff0) | (((u32)(src)<<4) & 0x003ffff0)) >> >> From this macro the first argument should be the present value in that >> register. Here you reset the address bits and write the new address bits. > > Yes.. This is correct. I am clearing x number of bit and then set new value. > >> IMO the first argument should be the value in 'csr_base + indirect_cmd_reg'. >> So it resets the address bits in 'csr_base + indirect_cmd_reg' and write >> down the new address bits. > > Yes.. The above code does just that. In addition, I am also setting > the bits CFG_IND_WR_CMD_MASK and CFG_IND_CMD_DONE_MASK with the two > previous statement. Think of the code flow as follow: > > val = readl(some void * address); /* read the register */
Where are you reading the register in your code (before CFG_IND_ADDR_SET)? > val = XXXX_SET(val, 0x1); /* set bit 0 - assuming XXXX set > bit 0 only */ If you want to set other bits (other than address) don't use CFG_IND_ADDR_SET macro. That looks hacky to me.
> val = YYYY_SET(val, 0x1); /* set bit 1 - assuming YYYY set > bit 1 only */ > val = ZZZZ_SET(val, 0x5); /* set upper 16 bit of the > register to 0x5 - assuming ZZZZ set field of the upper 16 bits */ > > Instead writing the above, I am replacing the above 4 lines with these > two lines: > > cmd = CFG_IND_WR_CMD_MASK | CFG_IND_CMD_DONE_MASK; > cmd = CFG_IND_ADDR_SET(cmd, addr); > > Is there clear? > > -Loc >
Cheers Kishon
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