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Message-ID: <bf3ea909-e0a5-eeac-12e9-c8a809685f48@ti.com> Date: Tue, 15 Feb 2022 21:03:52 +0530 From: Apurva Nandan <a-nandan@...com> To: Boris Brezillon <boris.brezillon@...labora.com> CC: Miquel Raynal <miquel.raynal@...tlin.com>, Richard Weinberger <richard@....at>, Vignesh Raghavendra <vigneshr@...com>, Mark Brown <broonie@...nel.org>, Patrice Chotard <patrice.chotard@...s.st.com>, Christophe Kerello <christophe.kerello@...s.st.com>, Daniel Palmer <daniel@...f.com>, Alexander Lobakin <alobakin@...me>, <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>, <linux-spi@...r.kernel.org>, <p.yadav@...com> Subject: Re: [PATCH v3 05/17] mtd: spinand: Define ctrl_ops for non-page read/write op templates Hi Boris, On 03/01/22 15:31, Boris Brezillon wrote: > On Sat, 1 Jan 2022 13:12:38 +0530 > Apurva Nandan <a-nandan@...com> wrote: > >> 'ctrl_ops' are op templates for non-page read/write operations, >> which are: reset, get_feature, set_feature, write_enable, block_erase, >> page_read and program_execute ops. The 'ctrl_ops' struct contains in it >> op templates for each of this op, as well as enum spinand_protocol >> denoting protocol of all these ops. >> >> We require these new op templates because of deviation in standard >> SPINAND ops by manufacturers and also due to changes when there is a >> change in SPI protocol/mode. This prevents the core from live-patching >> and vendor-specific adjustments in ops. >> >> Define 'ctrl_ops', add macros to initialize it and add it in >> spinand_device. >> >> Signed-off-by: Apurva Nandan <a-nandan@...com> >> --- >> include/linux/mtd/spinand.h | 33 +++++++++++++++++++++++++++++++++ >> 1 file changed, 33 insertions(+) >> >> diff --git a/include/linux/mtd/spinand.h b/include/linux/mtd/spinand.h >> index 439d8ce40e1d..e5df6220ec1e 100644 >> --- a/include/linux/mtd/spinand.h >> +++ b/include/linux/mtd/spinand.h >> @@ -356,6 +356,35 @@ struct spinand_op_variants { >> sizeof(struct spi_mem_op), \ >> } >> >> +struct spinand_ctrl_ops { >> + const struct { >> + struct spi_mem_op reset; >> + struct spi_mem_op get_feature; >> + struct spi_mem_op set_feature; >> + struct spi_mem_op write_enable; >> + struct spi_mem_op block_erase; >> + struct spi_mem_op page_read; >> + struct spi_mem_op program_execute; >> + } ops; >> + const enum spinand_protocol protocol; > Do you really need that protocol field? > >> +}; >> + >> +#define SPINAND_CTRL_OPS(__protocol, __reset, __get_feature, __set_feature, \ >> + __write_enable, __block_erase, __page_read, \ >> + __program_execute) \ >> + { \ >> + .ops = { \ >> + .reset = __reset, \ >> + .get_feature = __get_feature, \ >> + .set_feature = __set_feature, \ >> + .write_enable = __write_enable, \ >> + .block_erase = __block_erase, \ >> + .page_read = __page_read, \ >> + .program_execute = __program_execute, \ >> + }, \ >> + .protocol = __protocol, \ >> + } >> + >> /** >> * spinand_ecc_info - description of the on-die ECC implemented by a SPI NAND >> * chip >> @@ -468,6 +497,8 @@ struct spinand_dirmap { >> * @data_ops.read_cache: read cache op template >> * @data_ops.write_cache: write cache op template >> * @data_ops.update_cache: update cache op template >> + * @ctrl_ops: various SPI mem op templates for handling the flash device, i.e. >> + * non page-read/write ops. >> * @select_target: select a specific target/die. Usually called before sending >> * a command addressing a page or an eraseblock embedded in >> * this die. Only required if your chip exposes several dies >> @@ -498,6 +529,8 @@ struct spinand_device { >> const struct spi_mem_op *update_cache; >> } data_ops; >> >> + const struct spinand_ctrl_ops *ctrl_ops; >> + > Okay, I had something slightly different in mind. First, I'd put all > templates in a struct: > > struct spinand_op_templates { > const struct spi_mem_op *read_cache; > const struct spi_mem_op *write_cache; > const struct spi_mem_op *update_cache; > const struct spi_mem_op *reset; > const struct spi_mem_op *get_feature; > const struct spi_mem_op *set_feature; > const struct spi_mem_op *write_enable; > const struct spi_mem_op *block_erase; > const struct spi_mem_op *page_load; > const struct spi_mem_op *program_execute; > }; > > Then, at the spinand level, I'd define an array of templates: > > enum spinand_protocol { > SPINAND_1S_1S_1S, > SPINAND_2S_2S_2S, > SPINAND_4S_4S_4S, > SPINAND_8S_8S_8S, > SPINAND_8D_8D_8D, > SPINAND_NUM_PROTOCOLS, > }; > > struct spinand_device { > ... > enum spinand_protocol protocol; > const struct spinand_op_templates *op_templates[SPINAND_NUM_PROTOCOLS]; > ... > }; > > This way, you can easily pick the right set of operations based > on the protocol/mode you're in: > > #define spinand_get_op_template(spinand, opname) \ > ((spinand)->op_templates[(spinand)->protocol]->opname) > > static int spinand_read_reg_op(struct spinand_device *spinand, u8 reg, u8 *val) > { > struct spi_mem_op op = *spinand_get_op_template(spinand, get_feature); > int ret; > > ... > } I find a couple of issues with thisĀ method, 1. read_cache, write_cache, update_cache op templates don't fit well with the other non-data ops, as these data ops are used to create a dirmap, and that can be done only once at probe time. Hence, there is a different mechanism of selecting of data ops and non-data ops. Hence, this division in the op templates struct as data_ops and ctrl_ops is required. Currently, the core only supports using a single protocol for data ops, chosen at the time of probing. 2. If we use this single op_templates struct, I can't think of any good way to initialize these in the manufacturers driver (winbond.c), refer to 17th patch in this series. Could you please suggest a macro implementation also for winbond.c with the suggested op_templates struct. Thanks, Apurva Nandan
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