| Message ID | 1459218787-15197-1-git-send-email-yamada.masahiro@socionext.com |
|---|---|
| State | Superseded |
| Headers | show |
2016-03-29 11:33 GMT+09:00 Masahiro Yamada <yamada.masahiro@socionext.com>: > Commit 271707b1d817 ("mtd: nand: denali: max_banks calculation > changed in revision 5.1") supported the new encoding of the "n_banks" > bits of the "features" register, but there is an unfortunate case > not covered by that commit. > > Panasonic (its System LSI Business Division is now Socionext) bought > a couple of versions of this IP. The IP released for Panasonic > around Feb. 2012 is revision 5 and uses the old encoding for n_banks > (2 << n_banks). While the one released around Nov. 2012 is also > revision 5, but it uses the new encoding (1 << n_banks). > > The revision register cannot distinguish these two incompatible > hardware. I guess this IP series is not well-organized. I could not > find any solution but giving max_banks from DT property. > > This commit works around the problem by allowing DT to set the > max_banks forcibly. Of course, this DT property can be optional if > the auto detection based on the hardware registers works well. > > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > Acked-by: Rob Herring <robh@kernel.org> Looks like we should take our time for discussion to find out which is better, a new compatible string or a new DT property. The discussion is happening in v1 thread. http://patchwork.ozlabs.org/patch/601562/ Please hold back applying this patch.
diff --git a/Documentation/devicetree/bindings/mtd/denali-nand.txt b/Documentation/devicetree/bindings/mtd/denali-nand.txt index b04d03a..6154c77 100644 --- a/Documentation/devicetree/bindings/mtd/denali-nand.txt +++ b/Documentation/devicetree/bindings/mtd/denali-nand.txt @@ -7,6 +7,10 @@ Required properties: - interrupts : The interrupt number. - dm-mask : DMA bit mask +Optional properties: + - max-banks : Maximum number of banks supported by hardware. If not + specified, it is determined based on the "features" register of hardware. + The device tree may optionally contain sub-nodes describing partitions of the address space. See partition.txt for more detail. diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c index 30bf5f6..e18b569 100644 --- a/drivers/mtd/nand/denali.c +++ b/drivers/mtd/nand/denali.c @@ -1353,7 +1353,8 @@ static void denali_hw_init(struct denali_nand_info *denali) */ denali->bbtskipbytes = ioread32(denali->flash_reg + SPARE_AREA_SKIP_BYTES); - detect_max_banks(denali); + if (!denali->max_banks) + detect_max_banks(denali); denali_nand_reset(denali); iowrite32(0x0F, denali->flash_reg + RB_PIN_ENABLED); iowrite32(CHIP_EN_DONT_CARE__FLAG, diff --git a/drivers/mtd/nand/denali_dt.c b/drivers/mtd/nand/denali_dt.c index 0cb1e8d..be55db8 100644 --- a/drivers/mtd/nand/denali_dt.c +++ b/drivers/mtd/nand/denali_dt.c @@ -85,6 +85,9 @@ static int denali_dt_probe(struct platform_device *ofdev) denali->dev->dma_mask = NULL; } + of_property_read_u32(ofdev->dev.of_node, "max-banks", + &denali->max_banks); + dt->clk = devm_clk_get(&ofdev->dev, NULL); if (IS_ERR(dt->clk)) { dev_err(&ofdev->dev, "no clk available\n");
Commit 271707b1d817 ("mtd: nand: denali: max_banks calculation changed in revision 5.1") supported the new encoding of the "n_banks" bits of the "features" register, but there is an unfortunate case not covered by that commit. Panasonic (its System LSI Business Division is now Socionext) bought a couple of versions of this IP. The IP released for Panasonic around Feb. 2012 is revision 5 and uses the old encoding for n_banks (2 << n_banks). While the one released around Nov. 2012 is also revision 5, but it uses the new encoding (1 << n_banks). The revision register cannot distinguish these two incompatible hardware. I guess this IP series is not well-organized. I could not find any solution but giving max_banks from DT property. This commit works around the problem by allowing DT to set the max_banks forcibly. Of course, this DT property can be optional if the auto detection based on the hardware registers works well. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Rob Herring <robh@kernel.org> --- Changes in v2: - rebase on v4.6-rc1 - add Rob's Acked-by - Rephrase git-log slightly Documentation/devicetree/bindings/mtd/denali-nand.txt | 4 ++++ drivers/mtd/nand/denali.c | 3 ++- drivers/mtd/nand/denali_dt.c | 3 +++ 3 files changed, 9 insertions(+), 1 deletion(-)