From 965ebf33ea5afb6386f5b57cc71e6572253746b3 Mon Sep 17 00:00:00 2001 From: Haavard Skinnemoen Date: Wed, 17 Sep 2008 20:53:55 +0200 Subject: atmel-mci: support multiple mmc slots The Atmel MCI controller can drive multiple cards through separate sets of pins, but only one at a time. This patch adds support for multiplexing access to the controller so that multiple card slots can be used as if they were hooked up to separate mmc controllers. The atmel-mci driver registers each slot as a separate mmc_host. Both access the same common controller state, but they also have some state on their own for card detection/write protect handling, and separate shadows of the MR and SDCR registers. When one of the slots receives a request from the mmc core, the common controller state is checked. If it's idle, the request is submitted immediately. If not, the request is added to a queue. When a request is done, the queue is checked and if there is a queued request, it is submitted before the completion callback is called. This patch also includes a few cleanups and fixes, including a locking overhaul. I had to change the locking extensively in any case, so I might as well try to get it right. The driver no longer takes any irq-safe locks, which may or may not improve the overall system performance. This patch also adds a bit of documentation of the internal data structures. Signed-off-by: Haavard Skinnemoen --- arch/avr32/include/asm/atmel-mci.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'arch/avr32') diff --git a/arch/avr32/include/asm/atmel-mci.h b/arch/avr32/include/asm/atmel-mci.h index d38c64ca41e..5d5ae1295cf 100644 --- a/arch/avr32/include/asm/atmel-mci.h +++ b/arch/avr32/include/asm/atmel-mci.h @@ -1,6 +1,8 @@ #ifndef __ASM_AVR32_ATMEL_MCI_H #define __ASM_AVR32_ATMEL_MCI_H +#define ATMEL_MCI_MAX_NR_SLOTS 2 + /** * struct mci_slot_pdata - board-specific per-slot configuration * @bus_width: Number of data lines wired up the slot @@ -11,6 +13,10 @@ * set to 0. The other fields are ignored in this case. * * Any pins that aren't available should be set to a negative value. + * + * Note that support for multiple slots is experimental -- some cards + * might get upset if we don't get the clock management exactly right. + * But in most cases, it should work just fine. */ struct mci_slot_pdata { unsigned int bus_width; @@ -23,7 +29,7 @@ struct mci_slot_pdata { * @slot: Per-slot configuration data. */ struct mci_platform_data { - struct mci_slot_pdata slot[2]; + struct mci_slot_pdata slot[ATMEL_MCI_MAX_NR_SLOTS]; }; #endif /* __ASM_AVR32_ATMEL_MCI_H */ -- cgit v1.2.3