Re: [PATCH v3 06/10] mtd: intel-dg: wake card on operations

"Poosa, Karthik" <karthik.poosa@xxxxxxxxx> · Wed, 18 Dec 2024 10:43:13 +0530

On 18-12-2024 04:19, Rodrigo Vivi wrote:
On Tue, Nov 19, 2024 at 04:01:08PM +0200, Alexander Usyskin wrote:
Enable runtime PM in mtd driver to notify graphics driver that
whole card should be kept awake while nvm operations are
performed through this driver.

CC: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
Acked-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Signed-off-by: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
---
  drivers/mtd/devices/mtd-intel-dg.c | 70 +++++++++++++++++++++++++-----
  1 file changed, 58 insertions(+), 12 deletions(-)

diff --git a/drivers/mtd/devices/mtd-intel-dg.c b/drivers/mtd/devices/mtd-intel-dg.c
index 230bf444b7fe..9dd23b11ee95 100644
--- a/drivers/mtd/devices/mtd-intel-dg.c
+++ b/drivers/mtd/devices/mtd-intel-dg.c
@@ -15,11 +15,14 @@
  #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 500
+
  struct intel_dg_nvm {
  	struct kref refcnt;
  	struct mtd_info mtd;
@@ -460,6 +463,7 @@ static int intel_dg_mtd_erase(struct mtd_info *mtd, struct erase_info *info)
  	loff_t from;
  	size_t len;
  	size_t total_len;
+	int ret = 0;
  
  	if (WARN_ON(!nvm))
  		return -EINVAL;
@@ -474,20 +478,28 @@ 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(mtd->dev.parent);
on this, I really don't believe this is right and we should use
the parent child relation ship in our favor and only have the mtd
device to handle their own runtime pm...
I concur with Rodrigo. If the parent-child relationship is preserved, 
the parent will resume before the child, eliminating the need to 
explicitly wake the parent.
Please refer to https://docs.kernel.org/driver-api/pm/devices.html

The ordering of the device hierarchy is defined by the order in which 
devices get registered:
"a child can never be registered, probed or
resumed before its parent; "
and can’t be removed or suspended after that parent.

+	if (ret < 0) {
+		dev_err(&mtd->dev, "rpm: get failed %d\n", ret);
+		return ret;
+	}
+
  	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;
+			goto out;
  		}
  
  		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;
+			goto out;
  		}
  
  		from = addr - nvm->regions[idx].offset;
@@ -503,14 +515,18 @@ 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;
+			goto out;
  		}
  
  		addr += len;
  		total_len -= len;
  	}
  
-	return 0;
+out:
+	pm_runtime_mark_last_busy(mtd->dev.parent);
+	pm_runtime_put_autosuspend(mtd->dev.parent);
+	return ret;
  }
  
  static int intel_dg_mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
@@ -539,17 +555,25 @@ 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(mtd->dev.parent);
+	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_mark_last_busy(mtd->dev.parent);
+	pm_runtime_put_autosuspend(mtd->dev.parent);
+	return ret;
  }
  
  static int intel_dg_mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
@@ -578,17 +602,25 @@ 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(mtd->dev.parent);
+	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_mark_last_busy(mtd->dev.parent);
+	pm_runtime_put_autosuspend(mtd->dev.parent);
+	return ret;
  }
  
  static void intel_dg_nvm_release(struct kref *kref)
@@ -720,6 +752,17 @@ static int intel_dg_mtd_probe(struct auxiliary_device *aux_dev,
  		n++;
  	}
  
+	devm_pm_runtime_enable(device);
+
+	pm_runtime_set_autosuspend_delay(device, INTEL_DG_NVM_RPM_TIMEOUT);
+	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)) {
  		dev_err(device, "mmio not mapped\n");
@@ -742,9 +785,12 @@ 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







