linux-kernel - [PATCH] edac: mpc85xx: implement "remove" for mpc85xx_pci_err

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Date:   Thu, 17 Nov 2016 10:56:20 +0800
From:   <yanjiang.jin@...driver.com>
To:     <morbidrsa@...il.com>, <bp@...en8.de>, <mchehab@...nel.org>,
        <york.sun@....com>
CC:     <linux-edac@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <jinyanjing@...il.com>, <yanjiang.jin@...driver.com>
Subject: [PATCH] edac: mpc85xx: implement "remove" for mpc85xx_pci_err_driver

From: Yanjiang Jin <yanjiang.jin@...driver.com>

Tested on a T4240QDS board.

If we execute the below steps without this patch:

1. modprobe mpc85xx_edac [The first insmod, everything is well.]
2. modprobe -r mpc85xx_edac
3. modprobe mpc85xx_edac [insmod again, error happens.]

We would get the error messages as below:

BUG: recent printk recursion!
Oops: Kernel access of bad area, sig: 11 [#48]
Modules linked in: mpc85xx_edac edac_core softdog [last unloaded: mpc85xx_edac]
CPU: 5 PID: 14773 Comm: modprobe Tainted: G D C 4.8.3-rt2

 .vsnprintf
 .vscnprintf
 .vprintk_emit
 .printk
 .edac_pci_add_device
 .mpc85xx_pci_err_probe
 .platform_drv_probe
 .driver_probe_device
 .__driver_attach
 .bus_for_each_dev
 .driver_attach
 .bus_add_driver
 .driver_register
 .__platform_register_drivers
 .mpc85xx_mc_init
 .do_one_initcall
 .do_init_module
 .load_module
 .SyS_finit_module
 system_call

Signed-off-by: Yanjiang Jin <yanjiang.jin@...driver.com>
---
 drivers/edac/mpc85xx_edac.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/edac/mpc85xx_edac.c b/drivers/edac/mpc85xx_edac.c
index ff05675..c626021 100644
--- a/drivers/edac/mpc85xx_edac.c
+++ b/drivers/edac/mpc85xx_edac.c
@@ -300,6 +300,22 @@ static int mpc85xx_pci_err_probe(struct platform_device *op)
 	return res;
 }
 
+static int mpc85xx_pci_err_remove(struct platform_device *op)
+{
+	struct edac_pci_ctl_info *pci = dev_get_drvdata(&op->dev);
+	struct mpc85xx_pci_pdata *pdata = pci->pvt_info;
+
+	edac_dbg(0, "\n");
+
+	out_be32(pdata->pci_vbase + MPC85XX_PCI_ERR_ADDR, orig_pci_err_cap_dr);
+	out_be32(pdata->pci_vbase + MPC85XX_PCI_ERR_EN, orig_pci_err_en);
+
+	edac_pci_del_device(&op->dev);
+	edac_pci_free_ctl_info(pci);
+
+	return 0;
+}
+
 static const struct platform_device_id mpc85xx_pci_err_match[] = {
 	{
 		.name = "mpc85xx-pci-edac"
@@ -309,6 +325,7 @@ static int mpc85xx_pci_err_probe(struct platform_device *op)
 
 static struct platform_driver mpc85xx_pci_err_driver = {
 	.probe = mpc85xx_pci_err_probe,
+	.remove = mpc85xx_pci_err_remove,
 	.id_table = mpc85xx_pci_err_match,
 	.driver = {
 		.name = "mpc85xx_pci_err",
-- 
1.9.1