On Thu, Feb 5, 2015 at 4:37 AM, Brian Norris <computersforpeace@xxxxxxxxx> wrote: > On Tue, Jan 27, 2015 at 02:53:59PM +0800, Viet Nga Dao wrote: >> On Tue, Jan 20, 2015 at 10:05 AM, Viet Nga Dao <vndao@xxxxxxxxxx> wrote: >> > On Thu, Jan 15, 2015 at 5:27 PM, Viet Nga Dao <vndao@xxxxxxxxxx> wrote: >> >> On Tue, Jan 13, 2015 at 11:33 AM, Brian Norris >> >> <computersforpeace@xxxxxxxxx> wrote: >> >>> On Thu, Dec 18, 2014 at 12:23:16AM -0800, vndao@xxxxxxxxxx wrote: >> >>>> From: Viet Nga Dao <vndao@xxxxxxxxxx> > >> >> That is why if rewrite the drivers to follow spi-nor structure, it >> >> will require extra decoding works for the only few used opcodes. >> >> >> >I think you'd only have some very trivial work here. >> > >> >There would be some small work to reintroduce a properly-replaceable ID >> >table, and callbacks like ->lock() and ->unlock(), but those should be >> >implemented in spi-nor.c sooner or later anyway. >> > >> >> I am trying to modify the code to follow your recommendation. However, >> for lock and unlock functions, i have to implement it in spi_nor.c , >> am i right? If yes, currently we already have existing spi_nor_lock >> and spi_nor_unlock functions but they could not apply for my driver. >> Should i create a new functions named altera_epcq_lock and unlock and >> then map it to callback functions or i should the put those code >> sunder existing spi_nor_lock/unlock? > > We probably want a replaceable spi_nor callback that does the > flash-specific unlock. spi_nor_lock/unlock would then call the > nor->unlock() / nor->lock() functions for you, when present. > Some of the existing code should move into their own spi_nor_st_lock() / > spi_nor_st_unlock() functions. > When this will be implemented? As for time being, what should i do for these 2 functions? >> >>>> diff --git a/Documentation/devicetree/bindings/mtd/altera_epcq.txt b/Documentation/devicetree/bindings/mtd/altera_epcq.txt >> >>>> new file mode 100644 >> >>>> index 0000000..d14f50e >> >>>> --- /dev/null >> >>>> +++ b/Documentation/devicetree/bindings/mtd/altera_epcq.txt >> >>>> @@ -0,0 +1,45 @@ >> >>>> +* MTD Altera EPCQ driver >> >>>> + >> >>>> +Required properties: >> >>>> +- compatible: Should be "altr,epcq-1.0" >> >>>> +- reg: Address and length of the register set for the device. It contains >> >>>> + the information of registers in the same order as described by reg-names >> >>>> +- reg-names: Should contain the reg names >> >>>> + "csr_base": Should contain the register configuration base address >> >>>> + "data_base": Should contain the data base address >> >>>> +- is-epcs: boolean type. >> >>>> + If present, the device contains EPCS flashes. >> >>>> + Otherwise, it contains EPCQ flashes. >> >>>> +- #address-cells: Must be <1>. >> >>>> +- #size-cells: Must be <0>. >> >>>> +- flash device tree subnode, there must be a node with the following fields: >> >>> >> >>> These subnodes definitely require a 'compatible' string. Perhaps they >> >>> should be used to differentiate EPCS vs. EPCQ. Does "is-epcs" really >> >>> need to be in the top-level controller node? >> >>> >> >>>> + - reg: Should contain the flash id >> >>> >> >>> Should, or must? (This question is relevant, because you seem to make it >> >>> optional in your code.) And what does the "flash ID" mean? It seems like >> >>> you're using as a chip-select or bank index. >> >>> >> Yes, this is used for chip select. It is required, not optional. This >> to ID for each flash in the device > > OK, so correct the language here and enforce this in your driver. Right > now, you don't fail gracefully if this is missing. > >> >>>> + if (sector_start < num_sectors-(num_sectors / 4)) >> >>>> + sr_bp = __ilog2_u32(num_sectors); >> >>>> + else if (sector_start < num_sectors-(num_sectors / 8)) >> >>>> + sr_bp = __ilog2_u32(num_sectors) - 1; >> >>>> + else if (sector_start < num_sectors-(num_sectors / 16)) >> >>>> + sr_bp = __ilog2_u32(num_sectors) - 2; >> >>>> + else if (sector_start < num_sectors-(num_sectors / 32)) >> >>>> + sr_bp = __ilog2_u32(num_sectors) - 3; >> >>>> + else if (sector_start < num_sectors-(num_sectors / 64)) >> >>>> + sr_bp = __ilog2_u32(num_sectors) - 4; >> >>>> + else if (sector_start < num_sectors-(num_sectors / 128)) >> >>>> + sr_bp = __ilog2_u32(num_sectors) - 5; >> >>>> + else if (sector_start < num_sectors-(num_sectors / 256)) >> >>>> + sr_bp = __ilog2_u32(num_sectors) - 6; >> >>>> + else if (sector_start < num_sectors-(num_sectors / 512)) >> >>>> + sr_bp = __ilog2_u32(num_sectors) - 7; >> >>>> + else if (sector_start < num_sectors-(num_sectors / 1024)) >> >>>> + sr_bp = __ilog2_u32(num_sectors) - 8; >> >>>> + else >> >>>> + sr_bp = 0; /* non area protected */ >> >>> >> >>> Yikes, that's ugly! And I'm not sure it matches the EPCQ doc I found. >> >>> I'm pretty sure you can rewrite this if/else-if/else block in about 1 >> >>> line though. >> >>> >> Yes, i understand that it looks ugly. But it is the best i can do >> since this function has to satisfy for all the supported devices >> (http://www.altera.com.my/literature/hb/cfg/cfg_cf52012.pdf, start >> from page 19) > > Did you even try? It was possible to simplify the other case, and I'm > pretty sure this case can be simplified too. How about this? I hacked > this together and it seems to match: > > if (sector_start <= num_sectors / 2) > sr_bp = __ilog2_u32(num_sectors); > else > sr_bp = fls(num_sectors - 1 - sector_start) + 1; > >> >>>> + >> >>>> + if (sr_bp < 0) { >> >>> >> >>> sr_bp is unsigned, so this is never true. >> >>> >> Ok. I will change to int type. > > Are there ever negative values? > >> >>>> +static int altera_epcq_probe_config_dt(struct platform_device *pdev, >> >>>> + struct device_node *np, >> >>>> + struct altera_epcq_plat_data *pdata) >> >>>> +{ >> >>>> + struct device_node *pp = NULL; >> >>>> + struct resource *epcq_res; >> >>>> + int i = 0; >> >>>> + u32 id; > ... >> >>>> + pdata->np[i] = pp; >> >>>> + >> >>>> + /* Read bank id from DT */ >> >>>> + if (of_get_property(pp, "reg", &id)) > > I just realized; you're not using this correctly. of_get_property() > returns the *length* in the third parameter, so you're not actually > saving the bank ID here. You probably want of_property_read_u32() > instead. > >> >>> >> >>> Is this property optional? Your DT binding doc doesn't make it clear, >> >>> but it seems like a property which would be wise to require (i.e., not >> >>> optional). > > ^^^ so there should be a failure case, where you return failure if the > property is missing. > >> >>>> + pdata->board_flash_info[i].bank = id; >> >>>> + i++; >> >>>> + } >> >>>> + pdata->num_flashes = i; >> >>>> + return 0; >> >>>> +} > > Brian -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
