Messages in this thread | | | From | Dhananjay Phadke <> | Subject | Re: [PATCH 3/6] mtd: spi-nor: aspeed: Refactor registration/unregistration | Date | Tue, 5 Oct 2021 17:03:14 -0700 |
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On Wed, 29 Sep 2021, Zev Weiss wrote:
> We now have separate functions for registering and unregistering > individual flash chips, instead of the entire controller. This is a > preparatory step for allowing userspace to request that a specific > chip be attached or detached at runtime. > > Signed-off-by: Zev Weiss <zev@bewilderbeest.net> > --- > drivers/mtd/spi-nor/controllers/aspeed-smc.c | 73 ++++++++++++-------- > 1 file changed, 45 insertions(+), 28 deletions(-) > > diff --git a/drivers/mtd/spi-nor/controllers/aspeed-smc.c b/drivers/mtd/spi-nor/controllers/aspeed-smc.c > index 7225870e8b18..3c153104a905 100644 > --- a/drivers/mtd/spi-nor/controllers/aspeed-smc.c > +++ b/drivers/mtd/spi-nor/controllers/aspeed-smc.c > @@ -107,9 +107,10 @@ struct aspeed_smc_controller { > const struct aspeed_smc_info *info; /* type info of controller */ > void __iomem *regs; /* controller registers */ > void __iomem *ahb_base; /* per-chip windows resource */ > + struct resource *ahb_res; /* resource for AHB address space */ > u32 ahb_window_size; /* full mapping window size */ > > - struct aspeed_smc_chip *chips[]; /* pointers to attached chips */ > + struct aspeed_smc_chip *chips[]; /* pointers to connected chips */ > }; > > /* > @@ -399,15 +400,24 @@ static ssize_t aspeed_smc_write_user(struct spi_nor *nor, loff_t to, > return len; > } > > +static int aspeed_smc_unregister_chip(struct aspeed_smc_chip *chip) > +{ > + return mtd_device_unregister(&chip->nor.mtd); > +} > + > static int aspeed_smc_unregister(struct aspeed_smc_controller *controller) > { > struct aspeed_smc_chip *chip; > - int n; > + int n, ret; > > for (n = 0; n < controller->info->nce; n++) { > chip = controller->chips[n]; > - if (chip) > - mtd_device_unregister(&chip->nor.mtd); > + if (chip) { > + ret = aspeed_smc_unregister_chip(chip); > + if (ret) > + dev_warn(controller->dev, "failed to unregister CS%d: %d\n", > + n, ret); > + } > } > > return 0; > @@ -756,14 +766,39 @@ static const struct spi_nor_controller_ops aspeed_smc_controller_ops = { > .write = aspeed_smc_write_user, > }; > > -static int aspeed_smc_setup_flash(struct aspeed_smc_controller *controller, > - struct device_node *np, struct resource *r) > +static int aspeed_smc_register_chip(struct aspeed_smc_chip *chip) > { > - const struct spi_nor_hwcaps hwcaps = { > + static const struct spi_nor_hwcaps hwcaps = { > .mask = SNOR_HWCAPS_READ | > SNOR_HWCAPS_READ_FAST | > SNOR_HWCAPS_PP, > }; > + int ret; > + > + ret = aspeed_smc_chip_setup_init(chip, chip->controller->ahb_res); > + if (ret) > + goto out; > + > + /* > + * TODO: Add support for Dual and Quad SPI protocols attach when board > + * support is present as determined by of property. > + */ > + ret = spi_nor_scan(&chip->nor, NULL, &hwcaps); > + if (ret) > + goto out; > + > + ret = aspeed_smc_chip_setup_finish(chip); > + if (ret) > + goto out; > + > + ret = mtd_device_register(&chip->nor.mtd, NULL, 0); > +out: > + return ret; > +}
I was looking into this driver probe walking sub-nodes.
It looks like all controller drivers are doing / have to do similar work -
(1) Parse common dt bindings documented in Documentation/devicetree/bindings/mtd/jedec,spi-nor.yaml (2) Run spi_nor_scan() with tweaked/reduced capabilities. (3) mtd_register_device().
It would be good to absorb this workflow in mtd/spi-nor core and add 'reserved' as common dt property to avoid (2) and (3) from probe.
Regards, Dhananjay
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