[PATCH v6 05/11] mtd: intel-dg: register with mtd

Alexander Usyskin
2025-03-02T14:21:10Z

Register the on-die nvm device with the mtd subsystem.
Refcount nvm object on _get and _put mtd callbacks.
For erase operation address and size should be 4K aligned.
For write operation address and size has to be 4bytes aligned.

CC: Rodrigo Vivi <rodrigo.vivi@intel.com>
CC: Lucas De Marchi <lucas.demarchi@intel.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Co-developed-by: Tomas Winkler <tomasw@gmail.com>
Signed-off-by: Tomas Winkler <tomasw@gmail.com>
Co-developed-by: Vitaly Lubart <lubvital@gmail.com>
Signed-off-by: Vitaly Lubart <lubvital@gmail.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
---
drivers/mtd/devices/mtd_intel_dg.c | 230 ++++++++++++++++++++++++++++-
1 file changed, 226 insertions(+), 4 deletions(-)

diff --git a/drivers/mtd/devices/mtd_intel_dg.c b/drivers/mtd/devices/mtd_intel_dg.c
index 6f67cf966d05..4023f2ebc344 100644
--- a/drivers/mtd/devices/mtd_intel_dg.c
+++ b/drivers/mtd/devices/mtd_intel_dg.c
@@ -5,6 +5,7 @@

#include <linux/bitfield.h>
#include <linux/bits.h>
+#include <linux/cleanup.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/intel_dg_nvm_aux.h>
@@ -12,6 +13,8 @@
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/kernel.h>
#include <linux/module.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/sizes.h>
@@ -19,6 +22,8 @@

struct intel_dg_nvm {
struct kref refcnt;
+ struct mtd_info mtd;
+ struct mutex lock; /* region access lock */
void __iomem *base;
size_t size;
unsigned int nregions;
@@ -177,7 +182,6 @@ static int idg_nvm_is_valid(struct intel_dg_nvm *nvm)
return 0;
}

-__maybe_unused
static unsigned int idg_nvm_get_region(const struct intel_dg_nvm *nvm, loff_t from)
{
unsigned int i;
@@ -209,7 +213,6 @@ static ssize_t idg_nvm_rewrite_partial(struct intel_dg_nvm *nvm, loff_t to,
return len;
}

-__maybe_unused
static ssize_t idg_write(struct intel_dg_nvm *nvm, u8 region,
loff_t to, size_t len, const unsigned char *buf)
{
@@ -266,7 +269,6 @@ static ssize_t idg_write(struct intel_dg_nvm *nvm, u8 region,
return len;
}

-__maybe_unused
static ssize_t idg_read(struct intel_dg_nvm *nvm, u8 region,
loff_t from, size_t len, unsigned char *buf)
{
@@ -325,7 +327,6 @@ static ssize_t idg_read(struct intel_dg_nvm *nvm, u8 region,
return len;
}

-__maybe_unused
static ssize_t
idg_erase(struct intel_dg_nvm *nvm, u8 region, loff_t from, u64 len, u64 *fail_addr)
{
@@ -414,6 +415,147 @@ static int intel_dg_nvm_init(struct intel_dg_nvm *nvm, struct device *device)
return n;
}

+static int intel_dg_mtd_erase(struct mtd_info *mtd, struct erase_info *info)
+{
+ struct intel_dg_nvm *nvm = mtd->priv;
+ unsigned int idx;
+ u8 region;
+ u64 addr;
+ ssize_t bytes;
+ loff_t from;
+ size_t len;
+ size_t total_len;
+
+ if (WARN_ON(!nvm))
+ return -EINVAL;
+
+ if (!IS_ALIGNED(info->addr, SZ_4K) || !IS_ALIGNED(info->len, SZ_4K)) {
+ dev_err(&mtd->dev, "unaligned erase %llx %llx\n",
+ info->addr, info->len);
+ info->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
+ return -EINVAL;
+ }
+
+ total_len = info->len;
+ addr = info->addr;
+
+ guard(mutex)(&nvm->lock);
+
+ while (total_len > 0) {
+ if (!IS_ALIGNED(addr, SZ_4K) || !IS_ALIGNED(total_len, SZ_4K)) {
+ dev_err(&mtd->dev, "unaligned erase %llx %zx\n", addr, total_len);
+ info->fail_addr = addr;
+ return -ERANGE;
+ }
+
+ idx = idg_nvm_get_region(nvm, addr);
+ if (idx >= nvm->nregions) {
+ dev_err(&mtd->dev, "out of range");
+ info->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
+ return -ERANGE;
+ }
+
+ from = addr - nvm->regions[idx].offset;
+ region = nvm->regions[idx].id;
+ len = total_len;
+ if (len > nvm->regions[idx].size - from)
+ len = nvm->regions[idx].size - from;
+
+ dev_dbg(&mtd->dev, "erasing region[%d] %s from %llx len %zx\n",
+ region, nvm->regions[idx].name, from, len);
+
+ bytes = idg_erase(nvm, region, from, len, &info->fail_addr);
+ if (bytes < 0) {
+ dev_dbg(&mtd->dev, "erase failed with %zd\n", bytes);
+ info->fail_addr += nvm->regions[idx].offset;
+ return bytes;
+ }
+
+ addr += len;
+ total_len -= len;
+ }
+
+ return 0;
+}
+
+static int intel_dg_mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, u_char *buf)
+{
+ struct intel_dg_nvm *nvm = mtd->priv;
+ ssize_t ret;
+ unsigned int idx;
+ u8 region;
+
+ if (WARN_ON(!nvm))
+ return -EINVAL;
+
+ idx = idg_nvm_get_region(nvm, from);
+
+ dev_dbg(&mtd->dev, "reading region[%d] %s from %lld len %zd\n",
+ nvm->regions[idx].id, nvm->regions[idx].name, from, len);
+
+ if (idx >= nvm->nregions) {
+ dev_err(&mtd->dev, "out of range");
+ return -ERANGE;
+ }
+
+ from -= nvm->regions[idx].offset;
+ region = nvm->regions[idx].id;
+ if (len > nvm->regions[idx].size - from)
+ len = nvm->regions[idx].size - from;
+
+ guard(mutex)(&nvm->lock);
+
+ ret = idg_read(nvm, region, from, len, buf);
+ if (ret < 0) {
+ dev_dbg(&mtd->dev, "read failed with %zd\n", ret);
+ return ret;
+ }
+
+ *retlen = ret;
+
+ return 0;
+}
+
+static int intel_dg_mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
+ size_t *retlen, const u_char *buf)
+{
+ struct intel_dg_nvm *nvm = mtd->priv;
+ ssize_t ret;
+ unsigned int idx;
+ u8 region;
+
+ if (WARN_ON(!nvm))
+ return -EINVAL;
+
+ idx = idg_nvm_get_region(nvm, to);
+
+ dev_dbg(&mtd->dev, "writing region[%d] %s to %lld len %zd\n",
+ nvm->regions[idx].id, nvm->regions[idx].name, to, len);
+
+ if (idx >= nvm->nregions) {
+ dev_err(&mtd->dev, "out of range");
+ return -ERANGE;
+ }
+
+ to -= nvm->regions[idx].offset;
+ region = nvm->regions[idx].id;
+ if (len > nvm->regions[idx].size - to)
+ len = nvm->regions[idx].size - to;
+
+ guard(mutex)(&nvm->lock);
+
+ ret = idg_write(nvm, region, to, len, buf);
+ if (ret < 0) {
+ dev_dbg(&mtd->dev, "write failed with %zd\n", ret);
+ return ret;
+ }
+
+ *retlen = ret;
+
+ return 0;
+}
+
static void intel_dg_nvm_release(struct kref *kref)
{
struct intel_dg_nvm *nvm = container_of(kref, struct intel_dg_nvm, refcnt);
@@ -422,9 +564,80 @@ static void intel_dg_nvm_release(struct kref *kref)
pr_debug("freeing intel_dg nvm\n");
for (i = 0; i < nvm->nregions; i++)
kfree(nvm->regions[i].name);
+ mutex_destroy(&nvm->lock);
kfree(nvm);
}

+static int intel_dg_mtd_get_device(struct mtd_info *mtd)
+{
+ struct mtd_info *master = mtd_get_master(mtd);
+ struct intel_dg_nvm *nvm = master->priv;
+
+ if (WARN_ON(!nvm))
+ return -EINVAL;
+ pr_debug("get mtd %s %d\n", mtd->name, kref_read(&nvm->refcnt));
+ kref_get(&nvm->refcnt);
+
+ return 0;
+}
+
+static void intel_dg_mtd_put_device(struct mtd_info *mtd)
+{
+ struct mtd_info *master = mtd_get_master(mtd);
+ struct intel_dg_nvm *nvm = master->priv;
+
+ if (WARN_ON(!nvm))
+ return;
+ pr_debug("put mtd %s %d\n", mtd->name, kref_read(&nvm->refcnt));
+ kref_put(&nvm->refcnt, intel_dg_nvm_release);
+}
+
+static int intel_dg_nvm_init_mtd(struct intel_dg_nvm *nvm, struct device *device,
+ unsigned int nparts, bool writable_override)
+{
+ unsigned int i;
+ unsigned int n;
+ struct mtd_partition *parts = NULL;
+ int ret;
+
+ dev_dbg(device, "registering with mtd\n");
+
+ nvm->mtd.owner = THIS_MODULE;
+ nvm->mtd.dev.parent = device;
+ nvm->mtd.flags = MTD_CAP_NORFLASH | MTD_WRITEABLE;
+ nvm->mtd.type = MTD_DATAFLASH;
+ nvm->mtd.priv = nvm;
+ nvm->mtd._write = intel_dg_mtd_write;
+ nvm->mtd._read = intel_dg_mtd_read;
+ nvm->mtd._erase = intel_dg_mtd_erase;
+ nvm->mtd._get_device = intel_dg_mtd_get_device;
+ nvm->mtd._put_device = intel_dg_mtd_put_device;
+ nvm->mtd.writesize = SZ_1; /* 1 byte granularity */
+ nvm->mtd.erasesize = SZ_4K; /* 4K bytes granularity */
+ nvm->mtd.size = nvm->size;
+
+ parts = kcalloc(nvm->nregions, sizeof(*parts), GFP_KERNEL);
+ if (!parts)
+ return -ENOMEM;
+
+ for (i = 0, n = 0; i < nvm->nregions && n < nparts; i++) {
+ if (!nvm->regions[i].is_readable)
+ continue;
+ parts[n].name = nvm->regions[i].name;
+ parts[n].offset = nvm->regions[i].offset;
+ parts[n].size = nvm->regions[i].size;
+ if (!nvm->regions[i].is_writable && !writable_override)
+ parts[n].mask_flags = MTD_WRITEABLE;
+ n++;
+ }
+
+ ret = mtd_device_register(&nvm->mtd, parts, n);
+
+ kfree(parts);
+
+ return ret;
+}
+
static int intel_dg_mtd_probe(struct auxiliary_device *aux_dev,
const struct auxiliary_device_id *aux_dev_id)
{
@@ -454,6 +667,7 @@ static int intel_dg_mtd_probe(struct auxiliary_device *aux_dev,
return -ENOMEM;

kref_init(&nvm->refcnt);
+ mutex_init(&nvm->lock);

nvm->nregions = nregions;
for (n = 0, i = 0; i < INTEL_DG_NVM_REGIONS; i++) {
@@ -483,6 +697,12 @@ static int intel_dg_mtd_probe(struct auxiliary_device *aux_dev,
goto err;
}

+ ret = intel_dg_nvm_init_mtd(nvm, device, ret, invm->writable_override);
+ if (ret) {
+ dev_err(device, "failed init mtd %d\n", ret);
+ goto err;
+ }
+
dev_set_drvdata(&aux_dev->dev, nvm);

return 0;
@@ -499,6 +719,8 @@ static void intel_dg_mtd_remove(struct auxiliary_device *aux_dev)
if (!nvm)
return;

+ mtd_device_unregister(&nvm->mtd);
+
dev_set_drvdata(&aux_dev->dev, NULL);

kref_put(&nvm->refcnt, intel_dg_nvm_release);
--
2.43.0