[PATCH 10/58] mtd: rawnand: stm32_fmc2: retain open-handle state on removal

[James Hilliard]

Keep the embedded NAND chip and controller serialization state alive for
MTD references that survive unbind. Disconnect operations before
releasing DMA channels and scatterlists and asserting write protection;
defer NAND metadata cleanup and controller storage release until the
final reference.

Preserve immediate cleanup before publication and use the retained
lifetime after MTD registration has been attempted.

Fixes: 2cd457f328c1 ("mtd: rawnand: stm32_fmc2: add STM32 FMC2 NAND flash controller driver")
Signed-off-by: James Hilliard <james.hilliard1 at gmail.com>
---
 drivers/mtd/nand/raw/stm32_fmc2_nand.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/mtd/nand/raw/stm32_fmc2_nand.c b/drivers/mtd/nand/raw/stm32_fmc2_nand.c
index 9f42f8ab3212..4b89094c89e6 100644
--- a/drivers/mtd/nand/raw/stm32_fmc2_nand.c
+++ b/drivers/mtd/nand/raw/stm32_fmc2_nand.c
@@ -1902,6 +1902,11 @@ static int stm32_fmc2_nfc_set_cdev(struct stm32_fmc2_nfc *nfc)
 	return 0;
 }
 
+static void stm32_fmc2_nfc_release(struct nand_controller *controller)
+{
+	kfree(container_of(controller, struct stm32_fmc2_nfc, base));
+}
+
 static int stm32_fmc2_nfc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -1915,12 +1920,14 @@ static int stm32_fmc2_nfc_probe(struct platform_device *pdev)
 	int chip_cs, mem_region, ret, irq;
 	int start_region = 0;
 
-	nfc = devm_kzalloc(dev, sizeof(*nfc), GFP_KERNEL);
+	nfc = kzalloc_obj(*nfc);
 	if (!nfc)
 		return -ENOMEM;
+	ret = devm_nand_controller_init(dev, &nfc->base, stm32_fmc2_nfc_release);
+	if (ret)
+		return ret;
 
 	nfc->dev = dev;
-	nand_controller_init(&nfc->base);
 	nfc->base.ops = &stm32_fmc2_nfc_controller_ops;
 
 	nfc->data = of_device_get_match_data(dev);
@@ -2024,9 +2031,15 @@ static int stm32_fmc2_nfc_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_wp_enable;
 
-	ret = mtd_device_register(mtd, NULL, 0);
+	ret = nand_set_release(chip, NULL);
 	if (ret)
 		goto err_nand_cleanup;
+	ret = mtd_device_register(mtd, NULL, 0);
+	if (ret) {
+		nand_disconnect(chip);
+		mtd_put_master(mtd);
+		goto err_wp_enable;
+	}
 
 	platform_set_drvdata(pdev, nfc);
 
@@ -2061,7 +2074,7 @@ static void stm32_fmc2_nfc_remove(struct platform_device *pdev)
 
 	ret = mtd_device_unregister(nand_to_mtd(chip));
 	WARN_ON(ret);
-	nand_cleanup(chip);
+	nand_disconnect(chip);
 
 	if (nfc->dma_ecc_ch)
 		dma_release_channel(nfc->dma_ecc_ch);
@@ -2074,6 +2087,7 @@ static void stm32_fmc2_nfc_remove(struct platform_device *pdev)
 	sg_free_table(&nfc->dma_ecc_sg);
 
 	stm32_fmc2_nfc_wp_enable(nand);
+	mtd_put_master(nand_to_mtd(chip));
 }
 
 static int stm32_fmc2_nfc_suspend(struct device *dev)

-- 
2.53.0