sh_eth: fix TSU resource handling

When switching the driver to the managed device API, I managed to break the case of a dual Ether devices sharing a single TSU: the 2nd Ether port wouldn't probe. Iwamatsu-san has tried to fix this but his patch was buggy and he then dropped the ball...

The solution is to limit calling devm_request_mem_region() to the first of the two ports sharing the same TSU, so devm_ioremap_resource() can't be used anymore for the TSU resource...

---
The patch is against Dave Miller's 'net.git' repo.

 drivers/net/ethernet/renesas/sh_eth.c |   25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

Index: net/drivers/net/ethernet/renesas/sh_eth.c =================================--- net.orig/drivers/net/ethernet/renesas/sh_eth.c +++ net/drivers/net/ethernet/renesas/sh_eth.c
@@ -3225,10 +3225,29 @@ static int sh_eth_drv_probe(struct platf
/* ioremap the TSU registers */
if (mdp->cd->tsu) {
struct resource *rtsu;
+
rtsu = platform_get_resource(pdev, IORESOURCE_MEM, 1);
- mdp->tsu_addr = devm_ioremap_resource(&pdev->dev, rtsu);
- if (IS_ERR(mdp->tsu_addr)) {
- ret = PTR_ERR(mdp->tsu_addr);
+ if (!rtsu) {
+ dev_err(&pdev->dev, "no TSU resource\n");
+ ret = -ENODEV;
+ goto out_release;
+ }
+ /* We can only request the TSU region for the first port
+ * of the two sharing this TSU for the probe to succeed...
+ */
+ if (devno % 2 = 0 &&
+ !devm_request_mem_region(&pdev->dev, rtsu->start,
+ resource_size(rtsu),
+ dev_name(&pdev->dev))) {
+ dev_err(&pdev->dev, "can't request TSU resource.\n");
+ ret = -EBUSY;
+ goto out_release;
+ }
+ mdp->tsu_addr = devm_ioremap(&pdev->dev, rtsu->start,
+ resource_size(rtsu));
+ if (!mdp->tsu_addr) {
+ dev_err(&pdev->dev, "TSU region ioremap() failed.\n");
+ ret = -ENOMEM;
goto out_release;
}
mdp->port = devno % 2;

From: Sergei Shtylyov <[email protected]>
Date: Wed, 03 Jan 2018 20:09:49 +0300

Applied and queued up for -stable, thanks.