sh: pci: Support secondary FPGA-driven PCIe clocks on SDK7786.

The SDK7786 FPGA has secondary control over the PCIe clocks, specifically
relating to the slots and oscillator. This ties the FPGA clocks in to the
clock framework and balances the refcounting similar to how the primary
on-chip clocks are managed. While the on-chip clocks are per-port, the
FPGA clock enable/disable is global for the entire block.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 21 insertions, 2 deletions

diff --git a/arch/sh/drivers/pci/pcie-sh7786.c b/arch/sh/drivers/pci/pcie-sh7786.c
index 8ec4af197388..ae0b2c9b70a0 100644
--- a/arch/sh/drivers/pci/pcie-sh7786.c
+++ b/arch/sh/drivers/pci/pcie-sh7786.c
@@ -17,7 +17,6 @@
 #include <linux/sh_clk.h>
 #include "pcie-sh7786.h"
 #include <asm/sizes.h>
-#include <asm/clock.h>
 
 struct sh7786_pcie_port {
 	struct pci_channel	*hose;
@@ -510,6 +509,7 @@ static struct sh7786_pcie_hwops sh7786_65nm_pcie_hwops __initdata = {
 
 static int __init sh7786_pcie_init(void)
 {
+	struct clk *platclk;
 	int ret = 0, i;
 
 	printk(KERN_NOTICE "PCI: Starting initialization.\n");
@@ -527,6 +527,22 @@ static int __init sh7786_pcie_init(void)
 	if (unlikely(!sh7786_pcie_ports))
 		return -ENOMEM;
 
+	/*
+	 * Fetch any optional platform clock associated with this block.
+	 *
+	 * This is a rather nasty hack for boards with spec-mocking FPGAs
+	 * that have a secondary set of clocks outside of the on-chip
+	 * ones that need to be accounted for before there is any chance
+	 * of touching the existing MSTP bits or CPG clocks.
+	 */
+	platclk = clk_get(NULL, "pcie_plat_clk");
+	if (IS_ERR(platclk)) {
+		/* Sane hardware should probably get a WARN_ON.. */
+		platclk = NULL;
+	}
+
+	clk_enable(platclk);
+
 	printk(KERN_NOTICE "PCI: probing %d ports.\n", nr_ports);
 
 	for (i = 0; i < nr_ports; i++) {
@@ -539,8 +555,11 @@ static int __init sh7786_pcie_init(void)
 		ret |= sh7786_pcie_hwops->port_init_hw(port);
 	}
 
-	if (unlikely(ret))
+	if (unlikely(ret)) {
+		clk_disable(platclk);
+		clk_put(platclk);
 		return ret;
+	}
 
 	return 0;
 }