Commit 718004a5 authored by Uwe Kleine-König's avatar Uwe Kleine-König Committed by Miquel Raynal
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mtd: rawnand: pasemi: Don't use static data to track per-device state 



Up to now the pasemi nand driver only supported a single device
instance. However the check for that was racy because two parallel calls
of pasemi_nand_probe() could pass the check

	if (pasemi_nand_mtd)
		return -ENODEV;

before any of them assigns a non-NULL value to it.

So rework the driver to make use of per-device driver data.

As an intended side effect the driver can bind more than one device and
also gets rid of the check

	if (!pasemi_nand_mtd)
		return 0;

in the remove callback that could only ever trigger after the above race
happened.

Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarMiquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20230102124051.1508424-1-u.kleine-koenig@pengutronix.de
parent 34569d86

drivers/mtd/nand/raw/pasemi_nand.c

+35 −28
Original line number Diff line number Diff line
@@ -26,9 +26,12 @@ 
#define CLE_PIN_CTL			15

#define ALE_PIN_CTL			14



static unsigned int lpcctl;

static struct mtd_info *pasemi_nand_mtd;

static struct nand_controller controller;

struct pasemi_ddata {

	struct nand_chip chip;

	unsigned int lpcctl;

	struct nand_controller controller;

};



static const char driver_name[] = "pasemi-nand";



static void pasemi_read_buf(struct nand_chip *chip, u_char *buf, int len)
@@ -55,6 +58,8 @@ static void pasemi_write_buf(struct nand_chip *chip, const u_char *buf, 
static void pasemi_hwcontrol(struct nand_chip *chip, int cmd,

			     unsigned int ctrl)

{

	struct pasemi_ddata *ddata = container_of(chip, struct pasemi_ddata, chip);



	if (cmd == NAND_CMD_NONE)

		return;
@@ -65,12 +70,14 @@ static void pasemi_hwcontrol(struct nand_chip *chip, int cmd, 


	/* Push out posted writes */

	eieio();

	inl(lpcctl);

	inl(ddata->lpcctl);

}



static int pasemi_device_ready(struct nand_chip *chip)

{

	return !!(inl(lpcctl) & LBICTRL_LPCCTL_NR);

	struct pasemi_ddata *ddata = container_of(chip, struct pasemi_ddata, chip);



	return !!(inl(ddata->lpcctl) & LBICTRL_LPCCTL_NR);

}



static int pasemi_attach_chip(struct nand_chip *chip)
@@ -93,29 +100,31 @@ static int pasemi_nand_probe(struct platform_device *ofdev) 
	struct device_node *np = dev->of_node;

	struct resource res;

	struct nand_chip *chip;

	struct nand_controller *controller;

	int err = 0;

	struct pasemi_ddata *ddata;

	struct mtd_info *pasemi_nand_mtd;



	err = of_address_to_resource(np, 0, &res);



	if (err)

		return -EINVAL;



	/* We only support one device at the moment */

	if (pasemi_nand_mtd)

		return -ENODEV;



	dev_dbg(dev, "pasemi_nand at %pR\n", &res);



	/* Allocate memory for MTD device structure and private data */

	chip = kzalloc(sizeof(struct nand_chip), GFP_KERNEL);

	if (!chip) {

	ddata = kzalloc(sizeof(*ddata), GFP_KERNEL);

	if (!ddata) {

		err = -ENOMEM;

		goto out;

	}

	platform_set_drvdata(ofdev, ddata);

	chip = &ddata->chip;

	controller = &ddata->controller;



	controller.ops = &pasemi_ops;

	nand_controller_init(&controller);

	chip->controller = &controller;

	controller->ops = &pasemi_ops;

	nand_controller_init(controller);

	chip->controller = controller;



	pasemi_nand_mtd = nand_to_mtd(chip);
@@ -136,10 +145,10 @@ static int pasemi_nand_probe(struct platform_device *ofdev) 
		goto out_ior;

	}



	lpcctl = pci_resource_start(pdev, 0);

	ddata->lpcctl = pci_resource_start(pdev, 0);

	pci_dev_put(pdev);



	if (!request_region(lpcctl, 4, driver_name)) {

	if (!request_region(ddata->lpcctl, 4, driver_name)) {

		err = -EBUSY;

		goto out_ior;

	}
@@ -172,45 +181,43 @@ static int pasemi_nand_probe(struct platform_device *ofdev) 
	}



	dev_info(dev, "PA Semi NAND flash at %pR, control at I/O %x\n", &res,

		 lpcctl);

		 ddata->lpcctl);



	return 0;



 out_cleanup_nand:

	nand_cleanup(chip);

 out_lpc:

	release_region(lpcctl, 4);

	release_region(ddata->lpcctl, 4);

 out_ior:

	iounmap(chip->legacy.IO_ADDR_R);

 out_mtd:

	kfree(chip);

	kfree(ddata);

 out:

	return err;

}



static int pasemi_nand_remove(struct platform_device *ofdev)

{

	struct nand_chip *chip;

	struct pasemi_ddata *ddata = platform_get_drvdata(ofdev);

	struct mtd_info *pasemi_nand_mtd;

	int ret;

	struct nand_chip *chip;



	if (!pasemi_nand_mtd)

		return 0;



	chip = mtd_to_nand(pasemi_nand_mtd);

	chip = &ddata->chip;

	pasemi_nand_mtd = nand_to_mtd(chip);



	/* Release resources, unregister device */

	ret = mtd_device_unregister(pasemi_nand_mtd);

	WARN_ON(ret);

	nand_cleanup(chip);



	release_region(lpcctl, 4);

	release_region(ddata->lpcctl, 4);



	iounmap(chip->legacy.IO_ADDR_R);



	/* Free the MTD device structure */

	kfree(chip);



	pasemi_nand_mtd = NULL;

	kfree(ddata);



	return 0;

}