[PATCH v7 1/5] ARM: tegra: export apb dma readl/writel

Peter De Schrijver
2014-06-05T13:09:28Z

Export APB DMA readl and writel. These are needed because we can't access
the fuses directly on Tegra20 without potentially causing a system hang.
Also have the APB DMA readl and writel return an error in case of a read
failure instead of just returning zero or ignore write failures.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
---
arch/arm/mach-tegra/apbio.c | 51 ++++++++++++++++++++++++++----------------
include/linux/tegra-soc.h | 14 +++++++++++
2 files changed, 45 insertions(+), 20 deletions(-)

diff --git a/arch/arm/mach-tegra/apbio.c b/arch/arm/mach-tegra/apbio.c
index bc47197..e0bf49d 100644
--- a/arch/arm/mach-tegra/apbio.c
+++ b/arch/arm/mach-tegra/apbio.c
@@ -32,8 +32,8 @@ static u32 *tegra_apb_bb;
static dma_addr_t tegra_apb_bb_phys;
static DECLARE_COMPLETION(tegra_apb_wait);

-static u32 tegra_apb_readl_direct(unsigned long offset);
-static void tegra_apb_writel_direct(u32 value, unsigned long offset);
+static int tegra_apb_readl_direct(unsigned long offset, u32 *value);
+static int tegra_apb_writel_direct(u32 value, unsigned long offset);

static struct dma_chan *tegra_apb_dma_chan;
static struct dma_slave_config dma_sconfig;
@@ -128,58 +128,64 @@ static int do_dma_transfer(unsigned long apb_add,
return 0;
}

-static u32 tegra_apb_readl_using_dma(unsigned long offset)
+int tegra_apb_readl_using_dma(unsigned long offset, u32 *value)
{
int ret;

if (!tegra_apb_dma_chan && !tegra_apb_dma_init())
- return tegra_apb_readl_direct(offset);
+ return tegra_apb_readl_direct(offset, value);

mutex_lock(&tegra_apb_dma_lock);
ret = do_dma_transfer(offset, DMA_DEV_TO_MEM);
- if (ret < 0) {
+ if (ret < 0)
pr_err("error in reading offset 0x%08lx using dma\n", offset);
- *(u32 *)tegra_apb_bb = 0;
- }
+ else
+ *value = *tegra_apb_bb;
+
mutex_unlock(&tegra_apb_dma_lock);
- return *((u32 *)tegra_apb_bb);
+
+ return ret;
}

-static void tegra_apb_writel_using_dma(u32 value, unsigned long offset)
+int tegra_apb_writel_using_dma(u32 value, unsigned long offset)
{
int ret;

- if (!tegra_apb_dma_chan && !tegra_apb_dma_init()) {
- tegra_apb_writel_direct(value, offset);
- return;
- }
+ if (!tegra_apb_dma_chan && !tegra_apb_dma_init())
+ return tegra_apb_writel_direct(value, offset);

mutex_lock(&tegra_apb_dma_lock);
*((u32 *)tegra_apb_bb) = value;
ret = do_dma_transfer(offset, DMA_MEM_TO_DEV);
+ mutex_unlock(&tegra_apb_dma_lock);
if (ret < 0)
pr_err("error in writing offset 0x%08lx using dma\n", offset);
- mutex_unlock(&tegra_apb_dma_lock);
+
+ return ret;
}
#else
#define tegra_apb_readl_using_dma tegra_apb_readl_direct
#define tegra_apb_writel_using_dma tegra_apb_writel_direct
#endif

-typedef u32 (*apbio_read_fptr)(unsigned long offset);
-typedef void (*apbio_write_fptr)(u32 value, unsigned long offset);
+typedef int (*apbio_read_fptr)(unsigned long offset, u32 *value);
+typedef int (*apbio_write_fptr)(u32 value, unsigned long offset);

static apbio_read_fptr apbio_read;
static apbio_write_fptr apbio_write;

-static u32 tegra_apb_readl_direct(unsigned long offset)
+static int tegra_apb_readl_direct(unsigned long offset, u32 *value)
{
- return readl(IO_ADDRESS(offset));
+ *value = readl(IO_ADDRESS(offset));
+
+ return 0;
}

-static void tegra_apb_writel_direct(u32 value, unsigned long offset)
+static int tegra_apb_writel_direct(u32 value, unsigned long offset)
{
writel(value, IO_ADDRESS(offset));
+
+ return 0;
}

void tegra_apb_io_init(void)
@@ -197,7 +203,12 @@ void tegra_apb_io_init(void)

u32 tegra_apb_readl(unsigned long offset)
{
- return apbio_read(offset);
+ u32 val;
+
+ if (apbio_read(offset, &val) < 0)
+ return 0;
+ else
+ return val;
}

void tegra_apb_writel(u32 value, unsigned long offset)
diff --git a/include/linux/tegra-soc.h b/include/linux/tegra-soc.h
index 95f611d..b02d73b 100644
--- a/include/linux/tegra-soc.h
+++ b/include/linux/tegra-soc.h
@@ -19,4 +19,18 @@

u32 tegra_read_chipid(void);

+
+#if defined(CONFIG_TEGRA20_APB_DMA)
+int tegra_apb_readl_using_dma(unsigned long offset, u32 *value);
+int tegra_apb_writel_using_dma(u32 value, unsigned long offset);
+#else
+static inline int tegra_apb_readl_using_dma(unsigned long offset, u32 *value)
+{
+ return -EINVAL;
+}
+static inline int tegra_apb_writel_using_dma(u32 value, unsigned long offset)
+{
+ return -EINVAL;
+}
+#endif
#endif /* __LINUX_TEGRA_SOC_H_ */
--
1.7.7.rc0.72.g4b5ea.dirty