[PATCH v2] mtd: map: new driver for NXP IFC
Sanjay Tandel
sanjay.tandel at rockwellcollins.com
Wed Aug 30 17:03:48 PDT 2017
Hi Boris,
On Wed, Aug 30, 2017 at 2:34 PM, Boris Brezillon
<boris.brezillon at free-electrons.com> wrote:
> Hi,
>
> On Tue, 29 Aug 2017 14:47:27 -0500
> Matt Weber <matthew.weber at rockwellcollins.com> wrote:
>
>> From: Sanjay Tandel <sanjay.tandel at rockwellcollins.com>
>>
>> This patch adds map driver for parallel flash chips interfaced over
>> a NXP Integrated Flash Controller (IFC). This driver allows either
>> 8-bit or 16-bit accesses, depending on bank-width, to parallel flash
>> chips(like Everspin MR0A16A), which are physically mapped to CPU's
>> memory space. For unaligned accesses, it performs read-modify-write
>> operations to keep access size same as bank-width.
>>
>
> Did you consider re-using the physmap driver [1] and adjust it to your
> needs like the gemini [2] or versatile [3] drivers do? If you did, what
> prevents you from using this approach?
That approach would have coupled my driver with physmap driver, which has been
modified in newer version of kernel. So patch would not have been backward
compatible.
I intended to create independent driver without changing any existing
driver code.
>
> Regards,
>
> Boris
>
> [1]http://elixir.free-electrons.com/linux/v4.13-rc7/source/drivers/mtd/maps/physmap_of_core.c
> [2]http://elixir.free-electrons.com/linux/v4.13-rc7/source/drivers/mtd/maps/physmap_of_gemini.c
> [3]http://elixir.free-electrons.com/linux/v4.13-rc7/source/drivers/mtd/maps/physmap_of_versatile.c
>
Regards,
Sanjay
>> Signed-off-by: Sanjay Tandel <sanjay.tandel at rockwellcollins.com>
>> Signed-off-by: Matt Weber <matthew.weber at rockwellcollins.com>
>> ---
>>
>> Changes
>> v1 -> v2
>> - Refactored driver to be custom for the IFC bus controllder
>> (Suggested by Boris)
>> - Updated patch name
>> - Cleaned up description to be specific about issue and behavior
>> - Version 1 - https://patchwork.ozlabs.org/patch/797787/
>> ---
>> Documentation/devicetree/bindings/mtd/ifc-mram.txt | 34 ++
>> drivers/mtd/maps/Kconfig | 13 +
>> drivers/mtd/maps/Makefile | 1 +
>> drivers/mtd/maps/ifc_mram.c | 343 +++++++++++++++++++++
>> 4 files changed, 391 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/mtd/ifc-mram.txt
>> create mode 100644 drivers/mtd/maps/ifc_mram.c
>>
>> diff --git a/Documentation/devicetree/bindings/mtd/ifc-mram.txt b/Documentation/devicetree/bindings/mtd/ifc-mram.txt
>> new file mode 100644
>> index 0000000..c5c3210
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mtd/ifc-mram.txt
>> @@ -0,0 +1,34 @@
>> +Integrated Flash Controller based physically-mapped parallel MRAM,
>> +NOR flash, MTD-RAM (NVRAM...)
>> +
>> + - compatible : should contain the specific model of mtd chip(s)
>> + used, if known, followed by "ifc-mram".
>> + - reg : Address range(s) of the mtd chip(s)
>> + It's possible to (optionally) define multiple "reg" tuples so that
>> + non-identical chips can be described in one node.
>> + - bank-width : Width (in bytes) of the bank. Equal to the
>> + device width times the number of interleaved chips.
>> + - device-width : (optional) Width of a single mtd chip. If
>> + omitted, assumed to be equal to 'bank-width'.
>> + - #address-cells, #size-cells : Must be present if the device has
>> + sub-nodes representing partitions (see below). In this case
>> + both #address-cells and #size-cells must be equal to 1.
>> + - linux,mtd-name: allow to specify the mtd name.
>> +
>> +The device tree may optionally contain sub-nodes describing partitions of the
>> +address space. See partition.txt for more detail.
>> +
>> +Example:
>> +
>> + mram at 1,0 {
>> + #address-cells = <1>;
>> + #size-cells = <1>;
>> + compatible = "everspin,mram", "ifc-mram";
>> + reg = <0x1 0x0 0x10000 0x1 0x10000 0x10000>;
>> + bank-width = <2>;
>> +
>> + partition at 0 {
>> + reg = <0 0x00020000>;
>> + label = "MRAM Data 0";
>> + };
>> + };
>> diff --git a/drivers/mtd/maps/Kconfig b/drivers/mtd/maps/Kconfig
>> index 542fdf8..95bd44e 100644
>> --- a/drivers/mtd/maps/Kconfig
>> +++ b/drivers/mtd/maps/Kconfig
>> @@ -419,4 +419,17 @@ config MTD_LATCH_ADDR
>>
>> If compiled as a module, it will be called latch-addr-flash.
>>
>> +config MTD_IFC_MRAM
>> + tristate "Map driver for Integrated Flash Controller"
>> + depends on MTD_COMPLEX_MAPPINGS
>> + help
>> + Map driver for chips connected parallely to Integrated Flash
>> + Controller. This driver allows either 8-bit or 16-bit accesses,
>> + depending on bank-width, to parallel flash chips, which are
>> + physically mapped to CPU's memory space. For unaligned accesses,
>> + it does read-modify-write.
>> + Example: Everspin MR0A16A.
>> +
>> + If compiled as a module, it will be called ifc-mram.
>> +
>> endmenu
>> diff --git a/drivers/mtd/maps/Makefile b/drivers/mtd/maps/Makefile
>> index 5a09a72..0ab793e 100644
>> --- a/drivers/mtd/maps/Makefile
>> +++ b/drivers/mtd/maps/Makefile
>> @@ -47,3 +47,4 @@ obj-$(CONFIG_MTD_VMU) += vmu-flash.o
>> obj-$(CONFIG_MTD_GPIO_ADDR) += gpio-addr-flash.o
>> obj-$(CONFIG_MTD_LATCH_ADDR) += latch-addr-flash.o
>> obj-$(CONFIG_MTD_LANTIQ) += lantiq-flash.o
>> +obj-$(CONFIG_MTD_IFC_MRAM) += ifc_mram.o
>> diff --git a/drivers/mtd/maps/ifc_mram.c b/drivers/mtd/maps/ifc_mram.c
>> new file mode 100644
>> index 0000000..1341e0a
>> --- /dev/null
>> +++ b/drivers/mtd/maps/ifc_mram.c
>> @@ -0,0 +1,343 @@
>> +/*
>> + * Integrated Flash Controlller Map Driver
>> + *
>> + * Copyright 2017 Rockwell Collins
>> + *
>> + * Aug 18 2017 Sanjay Tandel <sanjay.tandel at rockwellcollins.com>
>> + *
>> + * Based on:
>> + * Flash mappings described by the OF (or flattened) device tree
>> + *
>> + * Copyright (C) 2006 MontaVista Software Inc.
>> + * Author: Vitaly Wool <vwool at ru.mvista.com>
>> + *
>> + * Revised to handle newer style flash binding by:
>> + * Copyright (C) 2007 David Gibson, IBM Corporation.
>> + *
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/types.h>
>> +#include <linux/device.h>
>> +#include <linux/mtd/mtd.h>
>> +#include <linux/mtd/map.h>
>> +#include <linux/mtd/partitions.h>
>> +#include <linux/mtd/concat.h>
>> +#include <linux/of.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_platform.h>
>> +#include <linux/slab.h>
>> +
>> +static const struct of_device_id ifc_mram_match[] = {
>> + {
>> + .compatible = "ifc-mram",
>> + },
>> + {}
>> +};
>> +MODULE_DEVICE_TABLE(of, ifc_mram_match);
>> +struct ifc_mram_list {
>> + struct mtd_info *mtd;
>> + struct map_info map;
>> + struct resource *res;
>> +};
>> +
>> +struct ifc_mram {
>> + struct mtd_info *cmtd;
>> + int list_size; /* number of elements in ifc_mram_list */
>> + struct ifc_mram_list list[0];
>> +};
>> +
>> +
>> +static void ifc_mram_copy_from8(void *to, void __iomem *from, size_t count)
>> +{
>> + u8 *t = to;
>> +
>> + while (count > 0) {
>> + *t = (u8)readb_relaxed(from);
>> + t++;
>> + from++;
>> + count--;
>> + }
>> +}
>> +
>> +static void ifc_mram_copy_from16(void *to, void __iomem *from, size_t count)
>> +{
>> + u8 *t = to;
>> +
>> + if (!(IS_ALIGNED((unsigned long)from, 2))) {
>> + from = (void __iomem *)ALIGN((unsigned long)from, 2) - 2;
>> + *(u8 *)t = (u8)((cpu_to_le16(readw_relaxed(from)) & 0xff00)
>> + >> 8);
>> + count--;
>> + t++;
>> + from += 2;
>> + }
>> + while (count >= 2) {
>> + *(u16 *)t = cpu_to_le16(readw_relaxed(from));
>> + count -= 2;
>> + t += 2;
>> + from += 2;
>> + };
>> + while (count > 0) {
>> + *(u8 *)t = (u8)(cpu_to_le16(readw_relaxed(from)) & 0x00ff);
>> + count--;
>> + t++;
>> + from++;
>> + }
>> +}
>> +
>> +static void ifc_mram_copy_from(struct map_info *map, void *to,
>> + unsigned long from, ssize_t len)
>> +{
>> + if (map->cached)
>> + memcpy(to, (char *)map->cached + from, len);
>> + else if (map_bankwidth_is_1(map))
>> + ifc_mram_copy_from8(to, map->virt + from, len);
>> + else if (map_bankwidth_is_2(map))
>> + ifc_mram_copy_from16(to, map->virt + from, len);
>> + else
>> + memcpy_fromio(to, map->virt + from, len);
>> +}
>> +
>> +static void ifc_mram_copy_to8(void __iomem *to, const void *from, size_t count)
>> +{
>> + const unsigned char *f = from;
>> +
>> + while (count > 0) {
>> + writeb_relaxed(*f, to);
>> + count--;
>> + to++;
>> + f++;
>> + }
>> +}
>> +
>> +static void ifc_mram_copy_to16(void __iomem *to, const void *from, size_t count)
>> +{
>> + const unsigned char *f = from;
>> + u16 d;
>> +
>> + if (!(IS_ALIGNED((unsigned long)to, 2))) {
>> + to = (void __iomem *)ALIGN((unsigned long)to, 2) - 2;
>> + d = (cpu_to_le16(readw_relaxed(to)) & 0x00ff)
>> + | ((u16)(*(const u8 *)f) << 8);
>> + writew_relaxed(le16_to_cpu(d), to);
>> + count--;
>> + to += 2;
>> + f++;
>> + }
>> + while (count >= 2) {
>> + writew_relaxed(le16_to_cpu(*(const u16 *)f), to);
>> + count -= 2;
>> + to += 2;
>> + f += 2;
>> + };
>> + while (count > 0) {
>> + d = (cpu_to_le16(readw_relaxed(to)) & 0xff00)
>> + | (u16)(*(const u8 *)f);
>> + writew_relaxed(le16_to_cpu(d), to);
>> + count--;
>> + to++;
>> + f++;
>> + }
>> +}
>> +
>> +static void ifc_mram_copy_to(struct map_info *map, unsigned long to,
>> + const void *from, ssize_t len)
>> +{
>> + if (map_bankwidth_is_1(map))
>> + ifc_mram_copy_to8(map->virt + to, from, len);
>> + else if (map_bankwidth_is_2(map))
>> + ifc_mram_copy_to16(map->virt + to, from, len);
>> + else
>> + memcpy_toio(map->virt + to, from, len);
>> +}
>> +static int ifc_mram_remove(struct platform_device *dev)
>> +{
>> + struct ifc_mram *info;
>> + int i;
>> +
>> + info = dev_get_drvdata(&dev->dev);
>> + if (!info)
>> + return 0;
>> + dev_set_drvdata(&dev->dev, NULL);
>> +
>> + if (info->cmtd) {
>> + mtd_device_unregister(info->cmtd);
>> + if (info->cmtd != info->list[0].mtd)
>> + mtd_concat_destroy(info->cmtd);
>> + }
>> +
>> + for (i = 0; i < info->list_size; i++) {
>> + if (info->list[i].mtd)
>> + map_destroy(info->list[i].mtd);
>> +
>> + if (info->list[i].map.virt)
>> + iounmap(info->list[i].map.virt);
>> +
>> + if (info->list[i].res) {
>> + release_resource(info->list[i].res);
>> + kfree(info->list[i].res);
>> + }
>> + }
>> + return 0;
>> +}
>> +
>> +static int ifc_mram_probe(struct platform_device *dev)
>> +{
>> + const struct of_device_id *match;
>> + struct device_node *dp = dev->dev.of_node;
>> + struct resource res;
>> + struct ifc_mram *info;
>> + const __be32 *width;
>> + int err;
>> + int i;
>> + int count;
>> + const __be32 *p;
>> + int reg_tuple_size;
>> + struct mtd_info **mtd_list = NULL;
>> + resource_size_t res_size;
>> + struct mtd_part_parser_data ppdata;
>> + bool map_indirect;
>> + const char *mtd_name = NULL;
>> +
>> + match = of_match_device(ifc_mram_match, &dev->dev);
>> + if (!match) {
>> + pr_info("%s: compatible string not matched\n", __func__);
>> + return -EINVAL;
>> + }
>> + reg_tuple_size =
>> + (of_n_addr_cells(dp) + of_n_size_cells(dp)) * sizeof(u32);
>> +
>> + of_property_read_string(dp, "linux,mtd-name", &mtd_name);
>> +
>> + p = of_get_property(dp, "reg", &count);
>> + if (count % reg_tuple_size != 0) {
>> + dev_err(&dev->dev, "Malformed reg property on %s\n",
>> + dev->dev.of_node->full_name);
>> + err = -EINVAL;
>> + goto err_flash_remove;
>> + }
>> + count /= reg_tuple_size;
>> +
>> + err = -ENOMEM;
>> + info = devm_kzalloc(&dev->dev,
>> + sizeof(struct ifc_mram) +
>> + sizeof(struct ifc_mram_list) * count, GFP_KERNEL);
>> + if (!info)
>> + goto err_flash_remove;
>> +
>> + dev_set_drvdata(&dev->dev, info);
>> +
>> + mtd_list = kcalloc(count, sizeof(*mtd_list), GFP_KERNEL);
>> + if (!mtd_list)
>> + goto err_flash_remove;
>> +
>> + for (i = 0; i < count; i++) {
>> + err = -ENXIO;
>> + if (of_address_to_resource(dp, i, &res)) {
>> + /*
>> + * Continue with next register tuple if this
>> + * one is not mappable
>> + */
>> + continue;
>> + }
>> +
>> + dev_dbg(&dev->dev, "ifc_mram device: %pR\n", &res);
>> +
>> + err = -EBUSY;
>> + res_size = resource_size(&res);
>> + info->list[i].res = request_mem_region(res.start, res_size,
>> + dev_name(&dev->dev));
>> + if (!info->list[i].res)
>> + goto err_out;
>> +
>> + err = -ENXIO;
>> + width = of_get_property(dp, "bank-width", NULL);
>> + if (!width) {
>> + dev_err(&dev->dev,
>> + "Can't get bank width from device tree\n");
>> + goto err_out;
>> + }
>> +
>> + info->list[i].map.name = mtd_name ?: dev_name(&dev->dev);
>> + info->list[i].map.phys = res.start;
>> + info->list[i].map.size = res_size;
>> + info->list[i].map.bankwidth = be32_to_cpup(width);
>> + info->list[i].map.device_node = dp;
>> +
>> + err = -ENOMEM;
>> + info->list[i].map.virt = ioremap(info->list[i].map.phys,
>> + info->list[i].map.size);
>> + if (!info->list[i].map.virt) {
>> + dev_err(&dev->dev,
>> + "Failed to ioremap() flash region\n");
>> + goto err_out;
>> + }
>> +
>> + simple_map_init(&info->list[i].map);
>> +#ifdef CONFIG_MTD_COMPLEX_MAPPINGS
>> + info->list[i].map.copy_from = ifc_mram_copy_from;
>> + info->list[i].map.copy_to = ifc_mram_copy_to;
>> +#endif
>> +
>> +
>> + info->list[i].mtd = do_map_probe("map_ram",
>> + &info->list[i].map);
>> + mtd_list[i] = info->list[i].mtd;
>> +
>> + err = -ENXIO;
>> + if (!info->list[i].mtd) {
>> + dev_err(&dev->dev, "do_map_probe() failed\n");
>> + goto err_out;
>> + } else {
>> + info->list_size++;
>> + }
>> + info->list[i].mtd->owner = THIS_MODULE;
>> + info->list[i].mtd->dev.parent = &dev->dev;
>> + }
>> +
>> + err = 0;
>> + info->cmtd = NULL;
>> + if (info->list_size == 1) {
>> + info->cmtd = info->list[0].mtd;
>> + } else if (info->list_size > 1) {
>> + /*
>> + * We detected multiple devices. Concatenate them together.
>> + */
>> + info->cmtd = mtd_concat_create(mtd_list, info->list_size,
>> + dev_name(&dev->dev));
>> + }
>> + if (info->cmtd == NULL)
>> + err = -ENXIO;
>> +
>> + if (err)
>> + goto err_out;
>> +
>> + ppdata.of_node = dp;
>> + mtd_device_parse_register(info->cmtd, NULL, &ppdata, NULL, 0);
>> + kfree(mtd_list);
>> + return 0;
>> +
>> +err_out:
>> + kfree(mtd_list);
>> +err_flash_remove:
>> + ifc_mram_remove(dev);
>> +
>> + return err;
>> +}
>> +
>> +
>> +static struct platform_driver ifc_mram_driver = {
>> + .driver = {
>> + .name = "ifc-mram",
>> + .of_match_table = ifc_mram_match,
>> + },
>> + .probe = ifc_mram_probe,
>> + .remove = ifc_mram_remove,
>> +};
>> +
>> +module_platform_driver(ifc_mram_driver);
>> +
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_AUTHOR("Sanjay Tandel");
>> +MODULE_DESCRIPTION("IFC MRAM Map Driver");
>
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