From: "Gupta, Pekon" <pekon@xxxxxx>
This patch enables usage of DT property 'gpmc,num-cs' as already documented in
Documentation/devicetree/bindings/bus/ti-gpmc.txt
Though GPMC hardware supports upto 8 chip-selects, but all chip-selects may
not be available for use because:
- chip-select pin may not be bonded out at SoC device boundary.
- chip-select pin-mux may conflict with other pins usage.
- board level constrains.
gpmc,num-cs allows user to configure maximum number of GPMC chip-selects
available for use on any given platform. This ensures:
- GPMC child nodes having chip-selects within allowed range are only probed.
- And un-used GPMC chip-selects remain blocked.(may be for security reasons).
Signed-off-by: Gupta, Pekon <pekon@xxxxxx>
---
arch/arm/mach-omap2/gpmc.c | 38 +++++++++++++++++++++++++++++---------
1 file changed, 29 insertions(+), 9 deletions(-)
diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
index 6c4da12..490bca8 100644
--- a/arch/arm/mach-omap2/gpmc.c
+++ b/arch/arm/mach-omap2/gpmc.c
@@ -155,6 +155,7 @@ static struct resource gpmc_cs_mem[GPMC_CS_NUM];
static DEFINE_SPINLOCK(gpmc_mem_lock);
/* Define chip-selects as reserved by default until probe completes */
static unsigned int gpmc_cs_map = ((1 << GPMC_CS_NUM) - 1);
+static unsigned int gpmc_cs_num = GPMC_CS_NUM;
static unsigned int gpmc_nr_waitpins;
static struct device *gpmc_dev;
static int gpmc_irq;
@@ -521,8 +522,10 @@ static int gpmc_cs_remap(int cs, u32 base)
int ret;
u32 old_base, size;
- if (cs > GPMC_CS_NUM)
+ if (cs > gpmc_cs_num) {
+ pr_err("%s: requested chip-select is disabled\n", __func__);
return -ENODEV;
+ }
gpmc_cs_get_memconf(cs, &old_base, &size);
if (base == old_base)
return 0;
@@ -545,9 +548,10 @@ int gpmc_cs_request(int cs, unsigned long size, unsigned long *base)
struct resource *res = &gpmc_cs_mem[cs];
int r = -1;
- if (cs > GPMC_CS_NUM)
+ if (cs > gpmc_cs_num) {
+ pr_err("%s: requested chip-select is disabled\n", __func__);
return -ENODEV;
-
+ }
size = gpmc_mem_align(size);
if (size > (1 << GPMC_SECTION_SHIFT))
return -ENOMEM;
@@ -582,7 +586,7 @@ EXPORT_SYMBOL(gpmc_cs_request);
void gpmc_cs_free(int cs)
{
spin_lock(&gpmc_mem_lock);
- if (cs >= GPMC_CS_NUM || cs < 0 || !gpmc_cs_reserved(cs)) {
+ if (cs >= gpmc_cs_num || cs < 0 || !gpmc_cs_reserved(cs)) {
printk(KERN_ERR "Trying to free non-reserved GPMC CS%d\n", cs);
BUG();
spin_unlock(&gpmc_mem_lock);
@@ -777,7 +781,7 @@ static void gpmc_mem_exit(void)
{
int cs;
- for (cs = 0; cs < GPMC_CS_NUM; cs++) {
+ for (cs = 0; cs < gpmc_cs_num; cs++) {
if (!gpmc_cs_mem_enabled(cs))
continue;
gpmc_cs_delete_mem(cs);
@@ -798,7 +802,7 @@ static void gpmc_mem_init(void)
gpmc_mem_root.end = GPMC_MEM_END;
/* Reserve all regions that has been set up by bootloader */
- for (cs = 0; cs < GPMC_CS_NUM; cs++) {
+ for (cs = 0; cs < gpmc_cs_num; cs++) {
u32 base, size;
if (!gpmc_cs_mem_enabled(cs))
@@ -1513,6 +1517,20 @@ static int gpmc_probe_dt(struct platform_device *pdev)
if (!of_id)
return 0;
+ ret = of_property_read_u32(pdev->dev.of_node, "gpmc,num-cs",
+ &gpmc_cs_num);
+ if (ret < 0) {
+ pr_err("%s: number of chip-selects not defined\n", __func__);
+ return ret;
+ } else if (gpmc_cs_num < 1) {
+ pr_err("%s: all chip-selects are disabled\n", __func__);
+ return -EINVAL;
+ } else if (gpmc_cs_num > GPMC_CS_NUM) {
+ pr_err("%s: number of supported chip-selects cannot be > %d\n",
+ __func__, GPMC_CS_NUM);
+ return -EINVAL;
+ }
+
ret = of_property_read_u32(pdev->dev.of_node, "gpmc,num-waitpins",
&gpmc_nr_waitpins);
if (ret < 0) {
@@ -1610,8 +1628,10 @@ static int gpmc_probe(struct platform_device *pdev)
/* Now the GPMC is initialised, unreserve the chip-selects */
gpmc_cs_map = 0;
- if (!pdev->dev.of_node)
+ if (!pdev->dev.of_node) {
+ gpmc_cs_num = GPMC_CS_NUM;
gpmc_nr_waitpins = GPMC_NR_WAITPINS;
+ }
rc = gpmc_probe_dt(pdev);
if (rc < 0) {
@@ -1715,7 +1735,7 @@ void omap3_gpmc_save_context(void)
gpmc_context.prefetch_config1 = gpmc_read_reg(GPMC_PREFETCH_CONFIG1);
gpmc_context.prefetch_config2 = gpmc_read_reg(GPMC_PREFETCH_CONFIG2);
gpmc_context.prefetch_control = gpmc_read_reg(GPMC_PREFETCH_CONTROL);
- for (i = 0; i < GPMC_CS_NUM; i++) {
+ for (i = 0; i < gpmc_cs_num; i++) {
gpmc_context.cs_context[i].is_valid = gpmc_cs_mem_enabled(i);
if (gpmc_context.cs_context[i].is_valid) {
gpmc_context.cs_context[i].config1 =
@@ -1747,7 +1767,7 @@ void omap3_gpmc_restore_context(void)
gpmc_write_reg(GPMC_PREFETCH_CONFIG1, gpmc_context.prefetch_config1);
gpmc_write_reg(GPMC_PREFETCH_CONFIG2, gpmc_context.prefetch_config2);
gpmc_write_reg(GPMC_PREFETCH_CONTROL, gpmc_context.prefetch_control);
- for (i = 0; i < GPMC_CS_NUM; i++) {
+ for (i = 0; i < gpmc_cs_num; i++) {
if (gpmc_context.cs_context[i].is_valid) {
gpmc_cs_write_reg(i, GPMC_CS_CONFIG1,
gpmc_context.cs_context[i].config1);
--
1.8.1
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