aboutsummaryrefslogtreecommitdiffstats
path: root/arch/arm/mach-tegra/apbio.c
Commit message (Collapse)AuthorAge
* ARM: tegra: apbio: use dmaengine based dma driverLaxman Dewangan2012-07-06
| | | | | | | | | | | | | | Use the dmaengine based Tegra APB DMA driver for apbio access in place of legacy Tegra APB DMA. The new driver is selected if legacy driver is not selected and new DMA driver is enabled through config file. Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com> [swarren: s/pr_err/pr_debug/ in tegra_apb_dma_init; this condition is expected to fire repeatedly before the DMA driver is available] Signed-off-by: Stephen Warren <swarren@nvidia.com>
* ARM: tegra: apbio access using dma for tegra20 onlyLaxman Dewangan2012-07-06
| | | | | | | | | | | | | The Tegra20 HW issue with accessing APBIO registers (such as fuse registers) directly from the CPU concurrently with APB DMA accesses has been fixed in Tegra30 and later chips. Access these registers directly from the CPU on Tegra30 and later, and apply the workaround only for Tegra20. Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com> Tested-by: Chaitanya Bandi <bandik@nvidia.com> Signed-off-by: Stephen Warren <swarren@nvidia.com>
* ARM: tegra: use APB DMA for accessing APB devicesOlof Johansson2012-02-06
Tegra2 hangs if APB registers are accessed from the cpu during an apb dma operation. The workaround is to use apb dma to read/write the registers instead. There is a dependency loop between fuses, clocks, and APBDMA. If dma is enabled, fuse reads must go through APBDMA to avoid corruption due to a hw bug. APBDMA requires a clock to be enabled. Clocks must read a fuse to determine allowable cpu frequencies. Separate out the fuse DMA initialization, and allow the fuse read and write functions to be called without using DMA before the DMA initialization has been completed. Access to the fuses before APBDMA is initialized won't hit the hardware bug because nothing else can be using DMA. Original fuse registar access code from Varun Wadekar <vwadekar@nvidia.com>, improved by Colin Cross <ccross@android.com> and later moved to separate driver by Jon Mayo <jmayo@nvidia.com>. Major refactoring/cleanup by Olof Johansson <olof@lixom.net>. Changes since v1: * fix 'return false' on error condition * dequeue dma ops in case of timeout From: Jon Mayo <jmayo@nvidia.com>. Signed-off-by: Jon Mayo <jmayo@nvidia.com>. Signed-off-by: Olof Johansson <olof@lixom.net> Acked-by: Stephen Warren <swarren@nvidia.com>