mtd: intel-dg: wake card on operations

The Intel DG cards do not have separate power control for
persistent memory.
The memory is available when the whole card is awake.

Enable runtime PM in mtd driver to notify parent graphics driver
that whole card should be kept awake while nvm operations are
performed through this driver.

Signed-off-by: Alexander Usyskin <[e-mail]>
Signed-off-by: Miquel Raynal <[e-mail]>

drivers/mtd/devices/mtd_intel_dg.c

···
 #include <linux/module.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/partitions.h>
+#include <linux/pm_runtime.h>
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/sizes.h>
 #include <linux/types.h>
 
+#define INTEL_DG_NVM_RPM_TIMEOUT_MS 500
+
 struct intel_dg_nvm {
 	struct kref refcnt;
 	struct mtd_info mtd;
+	struct device *dev;
 	struct mutex lock; /* region access lock */
 	void __iomem *base;
 	void __iomem *base2;
···
 	unsigned int i, n;
 	int ret;
 
+	nvm->dev = device;
+
 	/* clean error register, previous errors are ignored */
 	idg_nvm_error(nvm);
 
···
 	size_t len;
 	u8 region;
 	u64 addr;
+	int ret;
 
 	if (WARN_ON(!nvm))
 		return -EINVAL;
···
 	total_len = info->len;
 	addr = info->addr;
 
+	ret = pm_runtime_resume_and_get(nvm->dev);
+	if (ret < 0) {
+		dev_err(&mtd->dev, "rpm: get failed %d\n", ret);
+		return ret;
+	}
+
+	ret = 0;
 	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;
+			ret = -ERANGE;
+			break;
 		}
 
 		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;
+			ret = -ERANGE;
+			break;
 		}
 
 		from = addr - nvm->regions[idx].offset;
···
 		if (bytes < 0) {
 			dev_dbg(&mtd->dev, "erase failed with %zd\n", bytes);
 			info->fail_addr += nvm->regions[idx].offset;
-			return bytes;
+			ret = bytes;
+			break;
 		}
 
 		addr += len;
 		total_len -= len;
 	}
 
-	return 0;
+	pm_runtime_put_autosuspend(nvm->dev);
+	return ret;
 }
 
 static int intel_dg_mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
···
 	if (len > nvm->regions[idx].size - from)
 		len = nvm->regions[idx].size - from;
 
+	ret = pm_runtime_resume_and_get(nvm->dev);
+	if (ret < 0) {
+		dev_err(&mtd->dev, "rpm: get failed %zd\n", ret);
+		return ret;
+	}
+
 	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;
+	} else {
+		*retlen = ret;
+		ret = 0;
 	}
 
-	*retlen = ret;
-
-	return 0;
+	pm_runtime_put_autosuspend(nvm->dev);
+	return ret;
 }
 
 static int intel_dg_mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
···
 	if (len > nvm->regions[idx].size - to)
 		len = nvm->regions[idx].size - to;
 
+	ret = pm_runtime_resume_and_get(nvm->dev);
+	if (ret < 0) {
+		dev_err(&mtd->dev, "rpm: get failed %zd\n", ret);
+		return ret;
+	}
+
 	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;
+	} else {
+		*retlen = ret;
+		ret = 0;
 	}
 
-	*retlen = ret;
-
-	return 0;
+	pm_runtime_put_autosuspend(nvm->dev);
+	return ret;
 }
 
 static void intel_dg_nvm_release(struct kref *kref)
···
 	}
 	nvm->nregions = n; /* in case where kasprintf fail */
 
+	ret = devm_pm_runtime_enable(device);
+	if (ret < 0) {
+		dev_err(device, "rpm: enable failed %d\n", ret);
+		goto err_norpm;
+	}
+
+	pm_runtime_set_autosuspend_delay(device, INTEL_DG_NVM_RPM_TIMEOUT_MS);
+	pm_runtime_use_autosuspend(device);
+
+	ret = pm_runtime_resume_and_get(device);
+	if (ret < 0) {
+		dev_err(device, "rpm: get failed %d\n", ret);
+		goto err_norpm;
+	}
+
 	nvm->base = devm_ioremap_resource(device, &invm->bar);
 	if (IS_ERR(nvm->base)) {
 		ret = PTR_ERR(nvm->base);
···
 
 	dev_set_drvdata(&aux_dev->dev, nvm);
 
+	pm_runtime_put(device);
 	return 0;
 
 err:
+	pm_runtime_put(device);
+err_norpm:
 	kref_put(&nvm->refcnt, intel_dg_nvm_release);
 	return ret;
 }