From: Tomas Winkler <tomas.wink...@intel.com>

Register the on-die spi device with the mtd subsystem.
Refcount spi object on _get and _put mtd callbacks.

CC: Rodrigo Vivi <rodrigo.v...@intel.com>
CC: Lucas De Marchi <lucas.demar...@intel.com>
Signed-off-by: Tomas Winkler <tomas.wink...@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usys...@intel.com>
---
 drivers/gpu/drm/i915/spi/intel_spi_drv.c | 118 +++++++++++++++++++++++
 1 file changed, 118 insertions(+)

diff --git a/drivers/gpu/drm/i915/spi/intel_spi_drv.c 
b/drivers/gpu/drm/i915/spi/intel_spi_drv.c
index e3b78128ba76..355f9ad71602 100644
--- a/drivers/gpu/drm/i915/spi/intel_spi_drv.c
+++ b/drivers/gpu/drm/i915/spi/intel_spi_drv.c
@@ -15,8 +15,13 @@
 #include <linux/delay.h>
 #include "spi/intel_spi.h"
 
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+
 struct i915_spi {
        struct kref refcnt;
+       struct mtd_info mtd;
+       struct mutex lock; /* region access lock */
        void __iomem *base;
        size_t size;
        unsigned int nregions;
@@ -407,6 +412,29 @@ static int i915_spi_init(struct i915_spi *spi, struct 
device *device)
        return n;
 }
 
+static int i915_spi_erase(struct mtd_info *mtd, struct erase_info *info)
+{
+       dev_err(&mtd->dev, "erasing %lld %lld\n", info->addr, info->len);
+
+       return 0;
+}
+
+static int i915_spi_read(struct mtd_info *mtd, loff_t from, size_t len,
+                        size_t *retlen, u_char *buf)
+{
+       dev_err(&mtd->dev, "read %lld %zd\n", from, len);
+
+       return 0;
+}
+
+static int i915_spi_write(struct mtd_info *mtd, loff_t to, size_t len,
+                         size_t *retlen, const u_char *buf)
+{
+       dev_err(&mtd->dev, "writing %lld %zd\n", to, len);
+
+       return 0;
+}
+
 static void i915_spi_release(struct kref *kref)
 {
        struct i915_spi *spi = container_of(kref, struct i915_spi, refcnt);
@@ -415,9 +443,90 @@ static void i915_spi_release(struct kref *kref)
        pr_debug("freeing spi memory\n");
        for (i = 0; i < spi->nregions; i++)
                kfree(spi->regions[i].name);
+       mutex_destroy(&spi->lock);
        kfree(spi);
 }
 
+static int i915_spi_get_device(struct mtd_info *mtd)
+{
+       struct mtd_info *master;
+       struct i915_spi *spi;
+
+       if (!mtd)
+               return -ENODEV;
+
+       master = mtd_get_master(mtd);
+       spi = master->priv;
+       if (WARN_ON(!spi))
+               return -EINVAL;
+       pr_debug("get spi %s %d\n", mtd->name, kref_read(&spi->refcnt));
+       kref_get(&spi->refcnt);
+
+       return 0;
+}
+
+static void i915_spi_put_device(struct mtd_info *mtd)
+{
+       struct mtd_info *master;
+       struct i915_spi *spi;
+
+       if (!mtd)
+               return;
+
+       master = mtd_get_master(mtd);
+       spi = master->priv;
+       if (WARN_ON(!spi))
+               return;
+       pr_debug("put spi %s %d\n", mtd->name, kref_read(&spi->refcnt));
+       kref_put(&spi->refcnt, i915_spi_release);
+}
+
+static int i915_spi_init_mtd(struct i915_spi *spi, struct device *device,
+                            unsigned int nparts)
+{
+       unsigned int i;
+       unsigned int n;
+       struct mtd_partition *parts = NULL;
+       int ret;
+
+       dev_dbg(device, "registering with mtd\n");
+
+       spi->mtd.owner = THIS_MODULE;
+       spi->mtd.dev.parent = device;
+       spi->mtd.flags = MTD_CAP_NORFLASH | MTD_WRITEABLE;
+       spi->mtd.type = MTD_DATAFLASH;
+       spi->mtd.priv = spi;
+       spi->mtd._write = i915_spi_write;
+       spi->mtd._read = i915_spi_read;
+       spi->mtd._erase = i915_spi_erase;
+       spi->mtd._get_device = i915_spi_get_device;
+       spi->mtd._put_device = i915_spi_put_device;
+       spi->mtd.writesize = SZ_1; /* 1 byte granularity */
+       spi->mtd.erasesize = SZ_4K; /* 4K bytes granularity */
+       spi->mtd.size = spi->size;
+
+       parts = kcalloc(spi->nregions, sizeof(*parts), GFP_KERNEL);
+       if (!parts)
+               return -ENOMEM;
+
+       for (i = 0, n = 0; i < spi->nregions && n < nparts; i++) {
+               if (!spi->regions[i].is_readable)
+                       continue;
+               parts[n].name = spi->regions[i].name;
+               parts[n].offset  = spi->regions[i].offset;
+               parts[n].size = spi->regions[i].size;
+               if (!spi->regions[i].is_writable)
+                       parts[n].mask_flags = MTD_WRITEABLE;
+               n++;
+       }
+
+       ret = mtd_device_register(&spi->mtd, parts, n);
+
+       kfree(parts);
+
+       return ret;
+}
+
 static int i915_spi_probe(struct auxiliary_device *aux_dev,
                          const struct auxiliary_device_id *aux_dev_id)
 {
@@ -449,6 +558,7 @@ static int i915_spi_probe(struct auxiliary_device *aux_dev,
        if (!spi)
                return -ENOMEM;
 
+       mutex_init(&spi->lock);
        kref_init(&spi->refcnt);
 
        spi->nregions = nregions;
@@ -481,6 +591,12 @@ static int i915_spi_probe(struct auxiliary_device *aux_dev,
                goto err;
        }
 
+       ret = i915_spi_init_mtd(spi, device, ret);
+       if (ret) {
+               dev_err(device, "i915-spi failed init mtd %d\n", ret);
+               goto err;
+       }
+
        dev_set_drvdata(&aux_dev->dev, spi);
 
        dev_dbg(device, "i915-spi is bound\n");
@@ -499,6 +615,8 @@ static void i915_spi_remove(struct auxiliary_device 
*aux_dev)
        if (!spi)
                return;
 
+       mtd_device_unregister(&spi->mtd);
+
        dev_set_drvdata(&aux_dev->dev, NULL);
 
        kref_put(&spi->refcnt, i915_spi_release);
-- 
2.34.1

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