[PATCH] MIPS: pci-legacy: revert "use generic pci_enable_resources"

From: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>,
	linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Guenter Roeck <linux@roeck-us.net>
Subject: [PATCH] MIPS: pci-legacy: revert "use generic pci_enable_resources"
Date: Mon, 19 Apr 2021 23:39:43 -0700	[thread overview]
Message-ID: <20210420063942.7041-1-ilya.lipnitskiy@gmail.com> (raw)
In-Reply-To: <20210420052319.GA162457@roeck-us.net>

This mostly reverts commit 99bca615d895 ("MIPS: pci-legacy: use generic
pci_enable_resources"). Fixes regressions such as:
  ata_piix 0000:00:0a.1: can't enable device: BAR 0 [io  0x01f0-0x01f7] not
	claimed
  ata_piix: probe of 0000:00:0a.1 failed with error -22

The only changes from the strict revert are to fix checkpatch errors:
  ERROR: spaces required around that '=' (ctx:VxV)
  #33: FILE: arch/mips/pci/pci-legacy.c:252:
  +	for (idx=0; idx < PCI_NUM_RESOURCES; idx++) {
 	        ^

  ERROR: do not use assignment in if condition
  #67: FILE: arch/mips/pci/pci-legacy.c:284:
  +	if ((err = pcibios_enable_resources(dev, mask)) < 0)

Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
---
Guenter, sorry about this - let's just revert this for now to minimize
turmoil to the legacy PCI code. Obviously, this needs more testing
before applying. Thanks for your report!

 arch/mips/pci/pci-legacy.c | 38 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/arch/mips/pci/pci-legacy.c b/arch/mips/pci/pci-legacy.c
index c24226ea0a6e..468722c8a5c6 100644
--- a/arch/mips/pci/pci-legacy.c
+++ b/arch/mips/pci/pci-legacy.c
@@ -241,9 +241,45 @@ static int __init pcibios_init(void)
 
 subsys_initcall(pcibios_init);
 
+static int pcibios_enable_resources(struct pci_dev *dev, int mask)
+{
+	u16 cmd, old_cmd;
+	int idx;
+	struct resource *r;
+
+	pci_read_config_word(dev, PCI_COMMAND, &cmd);
+	old_cmd = cmd;
+	for (idx = 0; idx < PCI_NUM_RESOURCES; idx++) {
+		/* Only set up the requested stuff */
+		if (!(mask & (1<<idx)))
+			continue;
+
+		r = &dev->resource[idx];
+		if (!(r->flags & (IORESOURCE_IO | IORESOURCE_MEM)))
+			continue;
+		if ((idx == PCI_ROM_RESOURCE) &&
+				(!(r->flags & IORESOURCE_ROM_ENABLE)))
+			continue;
+		if (!r->start && r->end) {
+			pci_err(dev,
+				"can't enable device: resource collisions\n");
+			return -EINVAL;
+		}
+		if (r->flags & IORESOURCE_IO)
+			cmd |= PCI_COMMAND_IO;
+		if (r->flags & IORESOURCE_MEM)
+			cmd |= PCI_COMMAND_MEMORY;
+	}
+	if (cmd != old_cmd) {
+		pci_info(dev, "enabling device (%04x -> %04x)\n", old_cmd, cmd);
+		pci_write_config_word(dev, PCI_COMMAND, cmd);
+	}
+	return 0;
+}
+
 int pcibios_enable_device(struct pci_dev *dev, int mask)
 {
-	int err = pci_enable_resources(dev, mask);
+	int err = pcibios_enable_resources(dev, mask);
 
 	if (err < 0)
 		return err;
-- 
2.31.1

