[PATCH] soc: imx: gpc: restrict register range for regmap access

[Anson Huang]

GPC registers are NOT continuous, some registers are
reserved and accessing them from userspace will trigger
external abort, add regmap register access table to
avoid below abort:

root@imx6slevk:~# cat /sys/kernel/debug/regmap/20dc000.gpc/registers
[  108.480477] Unhandled fault: imprecise external abort (0x1406) at 0xb6db5004
[  108.487985] pgd = 42b54bfd
[  108.490741] [b6db5004] *pgd=ba1b7831
[  108.494386] Internal error: : 1406 [#1] SMP ARM
[  108.498943] Modules linked in:
[  108.502043] CPU: 0 PID: 389 Comm: cat Not tainted 4.18.0-rc1-00074-gc9f1f60-dirty #482
[  108.509982] Hardware name: Freescale i.MX6 SoloLite (Device Tree)
[  108.516123] PC is at regmap_mmio_read32le+0x20/0x24
[  108.521031] LR is at regmap_mmio_read+0x40/0x60
[  108.525586] pc : [<c059cf74>]    lr : [<c059d1ac>]    psr: 20060093
[  108.531875] sp : eccf1d98  ip : eccf1da8  fp : eccf1da4
[  108.537122] r10: ec2d3800  r9 : eccf1f60  r8 : ecfc0000
[  108.542370] r7 : eccf1e2c  r6 : eccf1e2c  r5 : 00000028  r4 : ec338e00
[  108.548920] r3 : 00000000  r2 : eccf1e2c  r1 : f0980028  r0 : 00000000
[  108.555474] Flags: nzCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment none
[  108.562720] Control: 10c5387d  Table: acf4004a  DAC: 00000051
[  108.568491] Process cat (pid: 389, stack limit = 0xd4318a65)
[  108.574174] Stack: (0xeccf1d98 to 0xeccf2000)

Signed-off-by: Anson Huang <Anson.Huang@xxxxxxx>
---
 drivers/soc/imx/gpc.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/soc/imx/gpc.c b/drivers/soc/imx/gpc.c
index 32f0748..0097a93 100644
--- a/drivers/soc/imx/gpc.c
+++ b/drivers/soc/imx/gpc.c
@@ -27,9 +27,16 @@
 #define GPC_PGC_SW2ISO_SHIFT	0x8
 #define GPC_PGC_SW_SHIFT	0x0
 
+#define GPC_PGC_PCI_PDN		0x200
+#define GPC_PGC_PCI_SR		0x20c
+
 #define GPC_PGC_GPU_PDN		0x260
 #define GPC_PGC_GPU_PUPSCR	0x264
 #define GPC_PGC_GPU_PDNSCR	0x268
+#define GPC_PGC_GPU_SR		0x26c
+
+#define GPC_PGC_DISP_PDN	0x240
+#define GPC_PGC_DISP_SR		0x24c
 
 #define GPU_VPU_PUP_REQ		BIT(1)
 #define GPU_VPU_PDN_REQ		BIT(0)
@@ -318,10 +325,24 @@ static const struct of_device_id imx_gpc_dt_ids[] = {
 	{ }
 };
 
+static const struct regmap_range yes_ranges[] = {
+	regmap_reg_range(GPC_CNTR, GPC_CNTR),
+	regmap_reg_range(GPC_PGC_PCI_PDN, GPC_PGC_PCI_SR),
+	regmap_reg_range(GPC_PGC_GPU_PDN, GPC_PGC_GPU_SR),
+	regmap_reg_range(GPC_PGC_DISP_PDN, GPC_PGC_DISP_SR),
+};
+
+static const struct regmap_access_table access_table = {
+	.yes_ranges	= yes_ranges,
+	.n_yes_ranges	= ARRAY_SIZE(yes_ranges),
+};
+
 static const struct regmap_config imx_gpc_regmap_config = {
 	.reg_bits = 32,
 	.val_bits = 32,
 	.reg_stride = 4,
+	.rd_table = &access_table,
+	.wr_table = &access_table,
 	.max_register = 0x2ac,
 };
 
-- 
2.7.4