Subject: [RFT PATCH v2 00/42] PCI: ARM/ARM64: remove pci_fixup_irqs() usage

From: [email-masked] (Lorenzo Pieralisi)
Date: Wed, 21 Jun 2017 11:45:38 +0100

On Wed, Jun 21, 2017 at 11:30:42AM +0100, Lorenzo Pieralisi wrote:
> On Wed, Jun 21, 2017 at 10:39:31AM +0200, Linus Walleij wrote:
> > On Thu, Jun 8, 2017 at 4:13 PM, Lorenzo Pieralisi
> > <[email-masked]> wrote:
> > 
> > I pulled this into the Gemini tree:
> > > [1] git://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/linux.git pci/pci-fixup-irqs-removal-v2
> > 
> > And then this happens:
> > 
> > OF: PCI: host bridge /soc/pci at 50000000 ranges:
> > OF: PCI:    IO 0x50000000..0x500fffff -> 0x00000000
> > OF: PCI:   MEM 0x58000000..0x5fffffff -> 0x58000000
> > Unable to handle kernel NULL pointer dereference at virtual address 00000070
> > pgd = c0004000
> > [00000070] *pgd=00000000
> > Internal error: Oops: 17 [#1] PREEMPT ARM
> > CPU: 0 PID: 254 Comm: kworker/0:1 Not tainted 4.12.0-rc3+ #888
> > Hardware name: Gemini (Device Tree)
> > Workqueue: events deferred_probe_work_func
> > task: c38c3a40 task.stack: c390a000
> > PC is at faraday_pci_probe+0x274/0x65c
> > LR is at __irq_put_desc_unlock+0x18/0x70
> > pc : [<c0232648>]    lr : [<c004be48>]    psr: 80000013
> > sp : c390bdf0  ip : c3424274  fp : c3ac2ee0
> > r10: c3f77718  r9 : c3ad49b0  r8 : c3907800
> > r7 : 00000004  r6 : c390be18  r5 : c3907810  r4 : c3ad4810
> > r3 : 00000000  r2 : 00000000  r1 : 00000001  r0 : c3ac2de0
> > Flags: Nzcv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
> > Control: 0000397f  Table: 03a9c000  DAC: 00000053
> > Process kworker/0:1 (pid: 254, stack limit = 0xc390a190)
> > Stack: (0xc390bdf0 to 0xc390c000)
> > bde0:                                     c0534a60 c3ad49b0 00000003 c024cb68
> > be00: 00000001 20000013 00000000 50000000 00000007 000020dd c3ae2680 c3ae2740
> > be20: c07c861f c0134328 00000000 c3ad5fa0 c3910a50 c3910a50 00000001 00000000
> > be40: 00000000 c01344ec c3910a50 c3910a50 00000001 00000000 c3910a50 c39d76e0
> > be60: c3ad5fa0 c05f6f58 c3910a50 c3907810 c3907810 c07cba88 fffffdfb 00000003
> > be80: 00000000 c07c5040 c386e420 c02bbbe0 c3907810 c081c6c4 00000000 c07cba88
> > bea0: 00000003 c02ba9dc 00000000 c390bee0 c02bab30 00000001 c07bf660 00000000
> > bec0: c07c5040 c02b93dc c382829c c39886f4 c3907810 c3907844 c3907810 c02ba674
> > bee0: c3907810 00000001 c390bf0c c3907810 c07d3a80 c3907810 c07d38e4 c02b961c
> > bf00: c3907810 c07d38d0 c07d38d0 c02ba210 c07d38ec c386e420 00000000 c3f6b100
> > bf20: c07bf660 c002dac0 00000008 c07bf660 c07bf660 c386e438 c390a000 c07bf674
> > bf40: 00000008 c07bf660 c07c5040 c002e044 c390a000 00000001 00000000 00000000
> > bf60: c3901518 c3901500 ffffe000 c38e2700 00000000 c3901518 c386e420 c002ddb4
> > bf80: c3839ee4 c00335ec c390a000 c38e2700 c003350c 00000000 00000000 00000000
> > bfa0: 00000000 00000000 00000000 c000a270 00000000 00000000 00000000 00000000
> > bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> > bfe0: 00000000 00000000 00000000 00000000 00000013 00000000 ffffffff ffffffff
> > [<c0232648>] (faraday_pci_probe) from [<c02bbbe0>]
> > (platform_drv_probe+0x50/0xb4)
> > [<c02bbbe0>] (platform_drv_probe) from [<c02ba9dc>]
> > (driver_probe_device+0x248/0x2dc)
> > [<c02ba9dc>] (driver_probe_device) from [<c02b93dc>]
> > (bus_for_each_drv+0x68/0x98)
> > [<c02b93dc>] (bus_for_each_drv) from [<c02ba674>] (__device_attach+0xa8/0x110)
> > [<c02ba674>] (__device_attach) from [<c02b961c>] (bus_probe_device+0x88/0x90)
> > [<c02b961c>] (bus_probe_device) from [<c02ba210>]
> > (deferred_probe_work_func+0x54/0x80)
> > [<c02ba210>] (deferred_probe_work_func) from [<c002dac0>]
> > (process_one_work+0x13c/0x430)
> > [<c002dac0>] (process_one_work) from [<c002e044>] (worker_thread+0x290/0x5f4)
> > [<c002e044>] (worker_thread) from [<c00335ec>] (kthread+0xe0/0x120)
> > [<c00335ec>] (kthread) from [<c000a270>] (ret_from_fork+0x14/0x24)
> > Code: e59401b0 e3700a01 8a00001d e59421ac (e5d23070)
> > ---[ end trace 1e313b1ea11e101c ]---
> > 
> > I'm trying to figure out what is causing it.
> 
> Mind trying this patch please on top of my branch (compile tested, that's
> all I can do)

Sorry I miss yet another usage of struct pci_bus before bus is
scanned in faraday_pci_parse_map_dma_ranges(), all these config
accessors want is to access bus number 0 and writei/read some config
values in there, please confirm.

Updated patch here:

-- >8 --
Subject: [PATCH] drivers: pci: host: ftpci100: Remove pre-scan bus dependency

Remove leftover pci_bus dependencies from the probe path.

Signed-off-by: Lorenzo Pieralisi <[email-masked]>
---
 drivers/pci/host/pci-ftpci100.c | 37 ++++++++++++++++++++++---------------
 1 file changed, 22 insertions(+), 15 deletions(-)

diff --git a/drivers/pci/host/pci-ftpci100.c b/drivers/pci/host/pci-ftpci100.c
index 9cfc90a..e938eeb 100644
--- a/drivers/pci/host/pci-ftpci100.c
+++ b/drivers/pci/host/pci-ftpci100.c
@@ -178,12 +178,11 @@ static int faraday_res_to_memcfg(resource_size_t mem_base,
 	return 0;
 }
 
-static int faraday_pci_read_config(struct pci_bus *bus, unsigned int fn,
-				   int config, int size, u32 *value)
+static int faraday_raw_pci_read_config(struct faraday_pci *p, int bus_number,
+				       unsigned int fn, int config, int size,
+				       u32 *value)
 {
-	struct faraday_pci *p = bus->sysdata;
-
-	writel(PCI_CONF_BUS(bus->number) |
+	writel(PCI_CONF_BUS(bus_number) |
 			PCI_CONF_DEVICE(PCI_SLOT(fn)) |
 			PCI_CONF_FUNCTION(PCI_FUNC(fn)) |
 			PCI_CONF_WHERE(config) |
@@ -197,11 +196,19 @@ static int faraday_pci_read_config(struct pci_bus *bus, unsigned int fn,
 	else if (size == 2)
 		*value = (*value >> (8 * (config & 3))) & 0xFFFF;
 
+	return PCIBIOS_SUCCESSFUL;
+}
+
+static int faraday_pci_read_config(struct pci_bus *bus, unsigned int fn,
+				   int config, int size, u32 *value)
+{
+	struct faraday_pci *p = bus->sysdata;
+
 	dev_dbg(&bus->dev,
 		"[read]  slt: %.2d, fnc: %d, cnf: 0x%.2X, val (%d bytes): 0x%.8X\n",
 		PCI_SLOT(fn), PCI_FUNC(fn), config, size, *value);
 
-	return PCIBIOS_SUCCESSFUL;
+	return faraday_raw_pci_read_config(p, bus->number, fn, config, size, value);
 }
 
 static int faraday_raw_pci_write_config(struct faraday_pci *p, int bus_number,
@@ -257,10 +264,10 @@ static void faraday_pci_ack_irq(struct irq_data *d)
 	struct faraday_pci *p = irq_data_get_irq_chip_data(d);
 	unsigned int reg;
 
-	faraday_pci_read_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, &reg);
+	faraday_raw_pci_read_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, &reg);
 	reg &= ~(0xF << PCI_CTRL2_INTSTS_SHIFT);
 	reg |= BIT(irqd_to_hwirq(d) + PCI_CTRL2_INTSTS_SHIFT);
-	faraday_pci_write_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, reg);
+	faraday_raw_pci_write_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, reg);
 }
 
 static void faraday_pci_mask_irq(struct irq_data *d)
@@ -268,10 +275,10 @@ static void faraday_pci_mask_irq(struct irq_data *d)
 	struct faraday_pci *p = irq_data_get_irq_chip_data(d);
 	unsigned int reg;
 
-	faraday_pci_read_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, &reg);
+	faraday_raw_pci_read_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, &reg);
 	reg &= ~((0xF << PCI_CTRL2_INTSTS_SHIFT)
 		 | BIT(irqd_to_hwirq(d) + PCI_CTRL2_INTMASK_SHIFT));
-	faraday_pci_write_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, reg);
+	faraday_raw_pci_write_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, reg);
 }
 
 static void faraday_pci_unmask_irq(struct irq_data *d)
@@ -279,10 +286,10 @@ static void faraday_pci_unmask_irq(struct irq_data *d)
 	struct faraday_pci *p = irq_data_get_irq_chip_data(d);
 	unsigned int reg;
 
-	faraday_pci_read_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, &reg);
+	faraday_raw_pci_read_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, &reg);
 	reg &= ~(0xF << PCI_CTRL2_INTSTS_SHIFT);
 	reg |= BIT(irqd_to_hwirq(d) + PCI_CTRL2_INTMASK_SHIFT);
-	faraday_pci_write_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, reg);
+	faraday_raw_pci_write_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, reg);
 }
 
 static void faraday_pci_irq_handler(struct irq_desc *desc)
@@ -291,7 +298,7 @@ static void faraday_pci_irq_handler(struct irq_desc *desc)
 	struct irq_chip *irqchip = irq_desc_get_chip(desc);
 	unsigned int irq_stat, reg, i;
 
-	faraday_pci_read_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, &reg);
+	faraday_raw_pci_read_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, &reg);
 	irq_stat = reg >> PCI_CTRL2_INTSTS_SHIFT;
 
 	chained_irq_enter(irqchip, desc);
@@ -412,8 +419,8 @@ static int faraday_pci_parse_map_dma_ranges(struct faraday_pci *p,
 		dev_info(dev, "DMA MEM%d BASE: 0x%016llx -> 0x%016llx config %08x\n",
 			 i + 1, range.pci_addr, end, val);
 		if (i <= 2) {
-			faraday_pci_write_config(p->bus, 0, confreg[i],
-						 4, val);
+			faraday_raw_pci_write_config(p, 0, 0, confreg[i],
+						     4, val);
 		} else {
 			dev_err(dev, "ignore extraneous dma-range %d\n", i);
 			break;
-- 
2.10.0