From ef34a3484bdf91187c00047a8a7bc3364a7efac4 Mon Sep 17 00:00:00 2001 From: "Gabriel L. Somlo" Date: Thu, 5 Nov 2015 09:32:51 -0500 Subject: fw_cfg: add generic non-DMA read method MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Introduce fw_cfg_data_read(), a generic read method which works on all access widths (1 through 8 bytes, inclusive), and can be used during both IOPort and MMIO read accesses. To maintain legibility, only fw_cfg_data_mem_read() (the MMIO data read method) is replaced by this patch. The new method essentially unwinds the fw_cfg_data_mem_read() + fw_cfg_read() combo, but without unnecessarily repeating all the validity checks performed by the latter on each byte being read. This patch also modifies the trace_fw_cfg_read prototype to accept a 64-bit value argument, allowing it to work properly with the new read method, but also remain backward compatible with existing call sites. Cc: Laszlo Ersek Cc: Gerd Hoffmann Cc: Marc Marí Signed-off-by: Gabriel Somlo Reviewed-by: Laszlo Ersek Message-id: 1446733972-1602-6-git-send-email-somlo@cmu.edu Signed-off-by: Gerd Hoffmann --- hw/nvram/fw_cfg.c | 45 +++++++++++++++++++++++++++++++-------------- trace-events | 2 +- 2 files changed, 32 insertions(+), 15 deletions(-) diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c index 046fa74..8f566f6 100644 --- a/hw/nvram/fw_cfg.c +++ b/hw/nvram/fw_cfg.c @@ -274,6 +274,36 @@ static int fw_cfg_select(FWCfgState *s, uint16_t key) return ret; } +static uint64_t fw_cfg_data_read(void *opaque, hwaddr addr, unsigned size) +{ + FWCfgState *s = opaque; + int arch = !!(s->cur_entry & FW_CFG_ARCH_LOCAL); + FWCfgEntry *e = (s->cur_entry == FW_CFG_INVALID) ? NULL : + &s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK]; + uint64_t value = 0; + + assert(size > 0 && size <= sizeof(value)); + if (s->cur_entry != FW_CFG_INVALID && e->data && s->cur_offset < e->len) { + /* The least significant 'size' bytes of the return value are + * expected to contain a string preserving portion of the item + * data, padded with zeros on the right in case we run out early. + * In technical terms, we're composing the host-endian representation + * of the big endian interpretation of the fw_cfg string. + */ + do { + value = (value << 8) | e->data[s->cur_offset++]; + } while (--size && s->cur_offset < e->len); + /* If size is still not zero, we *did* run out early, so continue + * left-shifting, to add the appropriate number of padding zeros + * on the right. + */ + value <<= 8 * size; + } + + trace_fw_cfg_read(s, value); + return value; +} + static uint8_t fw_cfg_read(FWCfgState *s) { int arch = !!(s->cur_entry & FW_CFG_ARCH_LOCAL); @@ -291,19 +321,6 @@ static uint8_t fw_cfg_read(FWCfgState *s) return ret; } -static uint64_t fw_cfg_data_mem_read(void *opaque, hwaddr addr, - unsigned size) -{ - FWCfgState *s = opaque; - uint64_t value = 0; - unsigned i; - - for (i = 0; i < size; ++i) { - value = (value << 8) | fw_cfg_read(s); - } - return value; -} - static void fw_cfg_data_mem_write(void *opaque, hwaddr addr, uint64_t value, unsigned size) { @@ -485,7 +502,7 @@ static const MemoryRegionOps fw_cfg_ctl_mem_ops = { }; static const MemoryRegionOps fw_cfg_data_mem_ops = { - .read = fw_cfg_data_mem_read, + .read = fw_cfg_data_read, .write = fw_cfg_data_mem_write, .endianness = DEVICE_BIG_ENDIAN, .valid = { diff --git a/trace-events b/trace-events index 3686e95..55f5b9e 100644 --- a/trace-events +++ b/trace-events @@ -196,7 +196,7 @@ ecc_diag_mem_readb(uint64_t addr, uint32_t ret) "Read diagnostic %"PRId64"= %02x # hw/nvram/fw_cfg.c fw_cfg_select(void *s, uint16_t key, int ret) "%p key %d = %d" -fw_cfg_read(void *s, uint8_t ret) "%p = %d" +fw_cfg_read(void *s, uint64_t ret) "%p = %"PRIx64 fw_cfg_add_file(void *s, int index, char *name, size_t len) "%p #%d: %s (%zd bytes)" # hw/block/hd-geometry.c -- cgit v1.1