[PATCH v3] mtd: intel-dg: wake card on operations

[Alexander Usyskin]

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 <alexander.usyskin at intel.com>
---

V3: Check return value of devm_pm_runtime_enable

V2: Address review comments (Andy)

 drivers/mtd/devices/mtd_intel_dg.c | 74 +++++++++++++++++++++++++-----
 1 file changed, 62 insertions(+), 12 deletions(-)

diff --git a/drivers/mtd/devices/mtd_intel_dg.c b/drivers/mtd/devices/mtd_intel_dg.c
index b438ee5aacc3..2bab30dcd35f 100644
--- a/drivers/mtd/devices/mtd_intel_dg.c
+++ b/drivers/mtd/devices/mtd_intel_dg.c
@@ -15,14 +15,18 @@
 #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;
@@ -421,6 +425,8 @@ static int intel_dg_nvm_init(struct intel_dg_nvm *nvm, struct device *device,
 	unsigned int i, n;
 	int ret;
 
+	nvm->dev = device;
+
 	/* clean error register, previous errors are ignored */
 	idg_nvm_error(nvm);
 
@@ -498,6 +504,7 @@ static int intel_dg_mtd_erase(struct mtd_info *mtd, struct erase_info *info)
 	size_t len;
 	u8 region;
 	u64 addr;
+	int ret;
 
 	if (WARN_ON(!nvm))
 		return -EINVAL;
@@ -512,20 +519,29 @@ static int intel_dg_mtd_erase(struct mtd_info *mtd, struct erase_info *info)
 	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;
@@ -541,14 +557,16 @@ static int intel_dg_mtd_erase(struct mtd_info *mtd, struct erase_info *info)
 		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,
@@ -577,17 +595,24 @@ 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,
@@ -616,17 +641,24 @@ 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)
@@ -753,6 +785,21 @@ static int intel_dg_mtd_probe(struct auxiliary_device *aux_dev,
 	}
 	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);
@@ -781,9 +828,12 @@ static int intel_dg_mtd_probe(struct auxiliary_device *aux_dev,
 
 	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;
 }
-- 
2.43.0