[PATCH 3/6] mtd: spi-nor: aspeed: Refactor registration/unregistration
Dhananjay Phadke
dphadke at linux.microsoft.com
Wed Oct 6 11:03:14 AEDT 2021
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 at 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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