summaryrefslogtreecommitdiff
path: root/drivers/bus
diff options
context:
space:
mode:
authorSven Van Asbroeck <thesven73@gmail.com>2018-12-17 10:48:00 -0500
committerShawn Guo <shawnguo@kernel.org>2019-01-11 15:16:45 +0800
commitc7995bcb36ef61e8b4136efab31ecf3c9b1633f9 (patch)
tree7f8be64f47e0407b4f2012df087de0d37cfcb5a3 /drivers/bus
parent8b8cb52af34da2faa293614b2554c8eac30faeaa (diff)
bus: imx-weim: guard against timing configuration conflicts
When specifying weim child devices, there is a risk that more than one timing setting is specified for the same chip select. The driver cannot support such a configuration. In case of conflict, this patch will print a warning to the log, and will ignore the child node in question. In this example, node acme@1 will be ignored, as it tries to modify timing settings for CS0: &weim { acme@0 { compatible = "acme,whatever"; reg = <0 0 0x100>; fsl,weim-cs-timing = <something>; }; acme@1 { compatible = "acme,whatnot"; reg = <0 0x500 0x100>; fsl,weim-cs-timing = <something else>; }; }; However in this example, the driver will be happy: &weim { acme@0 { compatible = "acme,whatever"; reg = <0 0 0x100>; fsl,weim-cs-timing = <something>; }; acme@1 { compatible = "acme,whatnot"; reg = <0 0x500 0x100>; fsl,weim-cs-timing = <something>; }; }; Signed-off-by: Sven Van Asbroeck <TheSven73@googlemail.com> Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Diffstat (limited to 'drivers/bus')
-rw-r--r--drivers/bus/imx-weim.c35
1 files changed, 32 insertions, 3 deletions
diff --git a/drivers/bus/imx-weim.c b/drivers/bus/imx-weim.c
index 1a0e0277a404..db74334ca5ef 100644
--- a/drivers/bus/imx-weim.c
+++ b/drivers/bus/imx-weim.c
@@ -46,8 +46,18 @@ static const struct imx_weim_devtype imx51_weim_devtype = {
};
#define MAX_CS_REGS_COUNT 6
+#define MAX_CS_COUNT 6
#define OF_REG_SIZE 3
+struct cs_timing {
+ bool is_applied;
+ u32 regs[MAX_CS_REGS_COUNT];
+};
+
+struct cs_timing_state {
+ struct cs_timing cs[MAX_CS_COUNT];
+};
+
static const struct of_device_id weim_id_table[] = {
/* i.MX1/21 */
{ .compatible = "fsl,imx1-weim", .data = &imx1_weim_devtype, },
@@ -112,15 +122,20 @@ err:
}
/* Parse and set the timing for this device. */
-static int __init weim_timing_setup(struct device_node *np, void __iomem *base,
- const struct imx_weim_devtype *devtype)
+static int __init weim_timing_setup(struct device *dev,
+ struct device_node *np, void __iomem *base,
+ const struct imx_weim_devtype *devtype,
+ struct cs_timing_state *ts)
{
u32 cs_idx, value[MAX_CS_REGS_COUNT];
int i, ret;
int reg_idx, num_regs;
+ struct cs_timing *cst;
if (WARN_ON(devtype->cs_regs_count > MAX_CS_REGS_COUNT))
return -EINVAL;
+ if (WARN_ON(devtype->cs_count > MAX_CS_COUNT))
+ return -EINVAL;
ret = of_property_read_u32_array(np, "fsl,weim-cs-timing",
value, devtype->cs_regs_count);
@@ -146,10 +161,23 @@ static int __init weim_timing_setup(struct device_node *np, void __iomem *base,
if (cs_idx >= devtype->cs_count)
return -EINVAL;
+ /* prevent re-configuring a CS that's already been configured */
+ cst = &ts->cs[cs_idx];
+ if (cst->is_applied && memcmp(value, cst->regs,
+ devtype->cs_regs_count * sizeof(u32))) {
+ dev_err(dev, "fsl,weim-cs-timing conflict on %pOF", np);
+ return -EINVAL;
+ }
+
/* set the timing for WEIM */
for (i = 0; i < devtype->cs_regs_count; i++)
writel(value[i],
base + cs_idx * devtype->cs_stride + i * 4);
+ if (!cst->is_applied) {
+ cst->is_applied = true;
+ memcpy(cst->regs, value,
+ devtype->cs_regs_count * sizeof(u32));
+ }
}
return 0;
@@ -163,6 +191,7 @@ static int __init weim_parse_dt(struct platform_device *pdev,
const struct imx_weim_devtype *devtype = of_id->data;
struct device_node *child;
int ret, have_child = 0;
+ struct cs_timing_state ts = {};
if (devtype == &imx50_weim_devtype) {
ret = imx_weim_gpr_setup(pdev);
@@ -171,7 +200,7 @@ static int __init weim_parse_dt(struct platform_device *pdev,
}
for_each_available_child_of_node(pdev->dev.of_node, child) {
- ret = weim_timing_setup(child, base, devtype);
+ ret = weim_timing_setup(&pdev->dev, child, base, devtype, &ts);
if (ret)
dev_warn(&pdev->dev, "%pOF set timing failed.\n",
child);